A Study of
Mandatory Engine Maintenance
for Reducing Vehicle Exhaust Emissions
Volume V. Experimental Investigation
of Service Organization Maintenance Performance
Year End Report
July 1972
In Support of:
APRAC Project Number CAPE-13-68
tor
Coordinating Research Council. Inc.
Thirty Rockefeller Plaza
New York. New York 10020
TRW
SYSTEMS GKOVP
ONE SPACE PARK REDONDO BEACH CALIFORNIA 902/8
and
Environmental Protection Agency
Air Pollution Control Olfice
5600 Fishers Lane
Rock\ille. Maryland 20852
SCOTT RESEARCH LABORATORIES, INC
P. O. BOX 24IC
SAN BERNARDINO. CALIFORNIA »Z4O«
-------
A Study of
Mandatory Engine Maintenance
for Reducing Vehicle Exhaust Emissions
Volume V. Experimental Investigation
of Service Organization Maintenance Performance
Year End Report
July 1972
In Support of:
APRAC Project Number CAPE-13-68
for
Coordinating Research Council. Inc.
Thirty Rockefeller Plaza
New York. New York 10020
and
Environmental Protection Agency
Air Pollution C'ontrol Office
5600 Fishers Lane
Rockxille. Mars land 20852
TRW
SYSTlMt
SCOTT RESEARCH LABORATORIES. INC
r o. BOX ui«
SAN BERNARDINO CALIFORNIA »I«O«
-------
PREFACE
This report, "A Study of Mandatory Engine Maintenance for Reducing
Vehicle Exhaust Emissions," consists of six volumes. The following are
the subtitles given for each volume:
Executive Summary, Volume I
t Mandatory Inspection/Maintenance Systems Study, Volume II
A Documentation Handbook for the Economic Effectiveness
Model, Volume III
Experimental Characterization of Vehicle Emissions and
Maintenance States, Volume IV
t Experimental Characterization of Service Organization
Maintenance Performance, Volume V
A Comparison of Oxides of Nitrogen Measurements Made With
Chemiluminescent and Non-Dispersive Radiation Analyzers,
Volume VI
The first volume summarizes the general objectives, approach and
results of the study. The second volume presents the results of the
mandatory inspection/maintenance system study conducted with a computer-
ized system model which is described in Volume III. The experimental
programs conducted to develop input data for the model are described in
Volume IV (Interim Report of 1971-72 Test Effort) and V. Volume VI
presents comparative measurements of NO and NO using chemiluminescence
A
and NDIR/NDUV instruments and differences in these measurements are
examined.
The work presented herein is the product of a joint effort by TRW
Systems Group and its subcontractor, Scott Research Laboratories. TRW,
as the prime contractor, was responsible for overall program management,
experimental design, data management and analysis, and the economic
effectiveness study. Scott acquired and tested all of the study vehicles,
Scott also provided technical assistance in selecting emission test
procedures and in evaluating the test results.
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION . , 1
2.0 MANDATORY INSPECTION MAINTENANCE APPROACHES SELECTED FOR
INVESTIGATION 3
3.0 VEHICLE AND ENGINE PART FAILURE OR MALADJUSTMENT SELECTION ... 5
3.1 Vehicle Selection 5
3.2 Malfunction Selection 5
4.0 EXPERIMENTAL PROGRAM 9
4.1 Vehicle Initial Preparation 9
4.2 Parameter Malfunction Methods .... 12
4.3 Service Organization Selection 12
4.4 Interface with Service Organizations .14
4.5 Test Program Description 15
5.0 RESULTS 30
5.1 Overview 30
5.2 Idle. Adjustment Repair Accuracy 33
5.3 Component Repair Accuracy 37
5.4 Repair Costs 39
5.5 Statistical Analysis 45
6.0 SUMMARY AND CONCLUSIONS 64
APPENDIX A - Supplementary Data 66
11
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LIST OF FIGURES
Figure Title Page
3-1 SIMS 1A - Garage Evaluation Fleet-Vehicle Malfunction
Distribution 6
4-1 Engine Parameter Inspection Summary 10
4-2 Malfunction Methods 13
4-3 Service Organization Evaluation Inspection Sheet 17
4-4 Typical Malfunctions which Cause High Exhaust Emissions 19
4-5 Truth Chart #1 - High HC @ Idle Only 20
4-6 Truth Chart #2 - High HC @ Idle and at Low Cruise 21
4-7 Truth Chart #3 - High HC @ Low and/or High Cruise 22
4-8 Truth Chart #4 - High HC in all Modes 23
4-9 Truth Chart #5 - High CO @ Idle 24
4-10 Truth Chart #6 - High CO @ Idle and at Low Cruise 25
4-11 Truth Chart #7 - High CO @ Low Cruise and/or High Cruise 26
4-12 Truth Chart #8 - High CO in all Modes of Operation 27
5-1 Vehicle Process Time 44
5-2 Mean Post-Tune Idle CO Deviation as a Function of Idle
CO Specification Value 50
5-3 Mean Post-Tune Idle RPM Deviation as a Function of Idle
RPM Specification Value 52
5-4 Mean Post-Tune Timing Deviation (in degrees) as a
Function of Pre-Tune Timing Deviation (in degrees) 54
111
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LIST OF TABLES
Tab!e Title Page
5-1 Malfunctions Detected and Corrected 31
5-2 Range of Detection or Repair of Malfunctioned Parameters
for all Vehicles Under all Experimental Conditions 32
5-3 Repair Accuracy 34
5-4 Variation of Repair Percentage Based Upon Different
Reference Specifications 36
5-5 Repair Accuracy for Malfunctions Requiring Repair or
Replacement 38
5-6 Average Repair Costs ($) 40
5-7 Summary of Excessive Repair Costs 42
5-8 Summary of Number of Unnecessary Repairs Performed 43
5-9 Results of Analyses of Variance Using the Complete Data
Set 46
5-10 Mean, Post Maintenance Idle CO Deviation in Percent as a
Function of City and Type of Service Organization 48
5-11 Mean Idle CO Deviation in Percent as a Function of Vehicle
and Service Instructions 49
5-12 Mean Cost in Dollars as a Function of City and Type of
Service Organization 53
5-13 Mean Idle Speed Deviation in RPM as a Function of Vehicle
and Instructions 55
5-14 Mean Timing Deviation in Degrees as a Function of Vehicle
and Service Instructions 56
5-15 Percent of NOX Control Device Replaced and Percent Mis-
fire (Spark Plug) Corrected for the Three Types of
Service Organizations 57
5-16 Percent of NOX Control Devices Replaced and Percent of
Spark Plug Misfire Corrected on Vehicles Under Emission
Instructions and on Vehicles Under Parameter Instructions 59
5-17 Percent of Plug Wire Misfires Corrected as a Function of
Service Instructions 59
5-18 Percent Heat Risers Adjusted as a Function of Instructions 61
iv
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LIST OF TABLES (Cont'd)
Table Title Page
5-19 Mean Cost in Dollars as a Function of Vehicle and
Service Instructions 62
A-l Ability of Service Organizations to Detect Malfunctions 67
A-2 Repair Accuracy (% of Vehicles within limits Idle CO) 68
A-3 Repair Accuracy (% of Vehicles within limits idle rpm) 69
A-4 Repair Accuracy (% of Vehicles within limits basic
timing) 70
A-5 Ability to Detect and Fix Malfunctions Other Than Idle
CO, rpm and Timing 71
A-6 Parameter Malfunction Detection and Repair Idle CO 72
A-7 Parameter Malfunction Detection and Repair Idle rpm 73
A-8 Parameter Malfunction Detection and Repair Basic Timing 74
A-9 Parameter Malfunction Detection and Repair Choke Blade 75
A-10 Parameter Malfunction Detection and Repair Air Cleaner 76
A-ll Parameter Malfunction Detection and Repair Misfire
(Spark Plug) 77
A-l2 Parameter Malfunction Detection and Repair Misfire
(Plug Wire) 78
A-l3 Parameter Malfunction Detection and Repair PCV Valve 79
A-14 Parameter Malfunction Detection and Repair Heat Riser 80
A-15 Parameter Malfunction Detection and Repair NOX Control
Device 81
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1.0 INTRODUCTION
The overall objective of this experiment was to develop measures
of service organization effectiveness in correcting engine part fail-
ures, malfunctions and tune-up parameter maladjustments which cause
high exhaust emissions. Subsidiary objectives were to assess the cap-
ability of service organizations to:
Detect specific malfunctions, maladjustments and failures
t Return malfunctions, maladjustments and failures to manu-
facturer's specifications
Respond to the type of information which might be provided
by mandatory vehicle inspection and the resulting impact
on cost and performance effectiveness.
It was also desired to develop statistics on the:
t Cost to accomplish maintenance
Maintenance cost and performance effectiveness of garages
organizations in different communities
Influence of service organization type (independent, dealership
and service station) on cost and performance effectiveness
The amount of unnecessary maintenance performed by service
organizations.
Quantitative data from these experiments which describes service
organization performance of maintenance which influences exhaust emissions
and maintenance costs are to be synthesized for use in the Economic Effect-
iveness Model.
The experimental program was conducted by systematically introducing
known malfunctions and maladjustments into test automobiles and submitting
the vehiclesto service organizations for repair. The malfunctions were
selected to be representative of the type of part failures and engine
parameter maladjustments found in the CAPE-13 Phase I engine parameter survey
while the levels of maladjustments were set to reflect the cost optimum
rejection levels predicted by the Economic Effectiveness Model. The mal-
functions are grouped by: Idle adjustments (RPM, F/A ratio, timing)
ignition system malfunctions (misfire from spark plug or
ignition wire) induction system upset (air cleaner plugging, PCV valve
1
-------
failure), choke system failure (heat riser failure and blade setting),
NO device failure and confounding malfunctions (rich float level and
A
valve failure).
The maladjusted vehicles were sent to service organizations for
repair. After service had been completed, Scott inspected the vehicles
to determine how well the maintenance organizations were able to detect
and repair the deliberately introduced malfunctions. The repair costs
were recorded and an estimate was made of unnecessary repairs performed
on each vehicle.
This report describes: (1) the program experimental design, (2)
experimental problems, (3) program results, and (4) recommendations for
further action.
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2.0 MANDATORY INSPECTION MAINTENANCE APPROACHES
SELECTED FOR INVESTIGATION
The TRW Economic Effectiveness study showed two basic inspection
approaches to be economically feasible for a mandatory vehicle inspection/
maintenance program.
A program in which a service organization would examine
engine parameter settings and components and repair those
items out of specification
t A program in which an actual emission measurement is made,
and data supplied to the repair agency describing the pro-
bable malfunctions and maladjustments which would produce
the measured high emissions.
In the experimental program, service organizations were provided with
maintenance data and instructions typical of that which might be provided
by each of these inspection processes.
The first inspection method requires direct inspection of engine
parameters using commercially available diagnostic equipment and pro-
cedures. Since California class "A" service organizations are likely to
use the most up to date commercially available engine parameter diagnostic
equipment and procedures, the inspection and repair of vehicles by these
organizations was considered representative of the best current state of
art of repair organizations. The experimental program therefore directly
evaluates the effectiveness of service organizations to diagnose and
maintain vehicles following a direct engine parameter inspection.
The second inspection method involves the measurement of exhaust
emissions under one or more engine operating conditions. Service organi-
zations then are provided with a list of probable vehicle maladjustments
and malfunctions based upon the resulting emissions data. The emissions
data also are provided. It was conceivable that the cost and reliability
of repair would be enhanced by the additional information, even though
the service organizations would still rely upon their standard commercial
diagnostic equipment and procedures. Data obtained from this portion of
-------
the program was used to evaluate service organization ability to diagnose
and maintain vehicles given data of the type obtainable from an exhaust
emission inspection.
Because the program was structured on the basis of the two inspection/
maintenance procedures, the test vehicles were divided into an engine para-
meter inspection fleet and an emission inspection fleet.
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3.0 VEHICLE AND ENGINE PART FAILURE OR
MALADJUSTMENT SELECTION
This section describes the criteria and methodology used in the
selection of test vehicles and engine part failures or maladjustments.
3.1 VEHICLE SELECTION
Five test vehicles each were selected for the engine parameter
inspection fleet and the emission inspection fleet. The mix of vehicles
by manufacturer was approximately in proportion to the national vehicle
population. All vehicles were equipped with popular engine/drive line
combinations (V-8 engines primarily with automatic transmissions) except
for the Volkswagen and American Motors vehicles.
It was estimated that the time required for a service organization to
process a vehicle would vary between one and two days. Thus the number of
vehicles used in the test program was determined to allow scheduling of
test vehicles into service organizations while maintaining a responably
stable work load at the Scott facility for setting up malfunctions and
checking service organization performance. In order to determine whether
service organizations would be biased in their performance by high mileage,
older vehicleSjOne 1965 pre-emission controlled GM vehicle was selected
for each fleet.
3.2 MALFUNCTION SELECTION
The goal was to introduce a large enough number of maladjustments and
malfunctions into each test vehicle to provide a data base of sufficient
size to evaluate the service organization detection and maintenance
capability while limiting malfunctions and maladjustments to those that
could reasonably be expected to occur in each particular vehicle.
Figure 3.1 shows the selected test vehicles and the parameter mal-
functions or deviations from the manufacturers' specifications which were
incorporated in each vehicle. The levels of deviation were based both
on the extent of maladjustment indicated in the CAPE-13 Phase I parameter
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Figure 3.1
SIMS 1A
Garage Evaluation Fleet - Vehicle Malfunction Distribution
Primary^Malfunction - Deviation From Nominal Specification
Vehicle
Identification
Car
1
2
3
4
5
6
7
8
9
10
Manufac-
turer
G.M.1
Ford
G.M.
Chry.
VW2
Chry.
G.M.1
Ford
G.M.
AMC2
Insp.
Type
Emiss.
n
it
ti
n
Par am.
n
n
it
Idle
X CO
+3.0
+3.5
+3.5
+3.0
0
0
+4.0
+4.0
+3.5
+3.5
rpm
0
-70
-70
0
+50
+50
-50
-50
-150
-150
Timing
Basic
+10
+2
+2
+10
-10
+10
+7
+10
+10
-5
NOX
Misfire
Plus
Control Wire
~
(Inoper.
( - )
Inoper.
~
Inoper.
Inoper.
(")
12%
)(12%D)
--
( - )
»«
(12Z)
Spk.
Plug
(6%)
( - )
6%
(6%)
Induction Confounding
System Choke System Malfunction
Air
Clnr. Heat Blade
% CO3 PCV Riser Setting
(+.5) (Failed4) (Failed6) __ Rich Float Level
Bent Push Rods
(-) <~>
+.5 ( ~ )
(-) <">
Failed5 .-1/8" (Rich)
+.2 (Failed)
+.2
( ) Failed6 -1/8" (Rich)
(-) ( > - -
NOTES:
1 Pre-controlled vehicle, all others are 1970-71 vehicles ( ) . indicates change from original chart
i All vehicles are V-8's except AMC and VW
' Or 180* maximum on AC tester
4 Plugged
* Open
6 Closed
^ Disconnected
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survey data and the optimum rejection levels predicted by the Economic/
Effectiveness Model. The number of malfunctions selected for a single
vehicle as well as the total number of malfunctions studied was constrained
to conform to the following additional criteria:
t The malfunctions were apportioned as equally as possible
among vehicles
t A minimum test sample size (across the total vehicle sample)
of 90 was required for each parameter under study
In addition, confounding malfunctions of two types were introduced
into vehicles of the emission inspection fleet. These were malfunctions
which would result in high emissions under several engine operating
modes, and would tend to mask the influence of the particular parameters
under evaluation. For example, vehicle #1 contained a number of induction
system related malfunctions causing high CO emissions under load. In
addition, the carburetor float level was set to cause rich mixture, thus
resulting in even higher CO and HC emissions. A choke-related malfunction
(heat riser fixed open) which would not be detected by tests performed
with a hot engine was also introduced. Vehicle #2 contained a number of
engine parameter maladjustments which tended to cause high HC emissions
under load. A bent push rod was introduced as a confounding malfunction
(simulating valve failure) to mask a misfire malfunction.
The objective of introducing confounding malfunctions was to assess
whether the service organization would over-react to confounding malfunc-
tions by over-repairing the carburetor rather than maintaining simple
components (PCV and air cleaner which also affect carburetor metering)
by failing to detect the heat riser failure because it would not be
detected by hot engine inspection, or by failing to detect the misfire
malfunction since the simulated valve failure would have the same effect
on emissions.
Vehicles 1 through 5 made up the emission inspection fleet. Vehicles
6 through 10 the parameter inspection fleet. As can be seen from Figure
3.1, a pre-controlled vehicle was included in each fleet. These older
vehicles allowed the introduction of malfunctions likely to occur in
older vehicles which are not probable in later model year vehicles.
7
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This matrix of malfunctions resulted in a higher number of malfunctions
per vehicle than is normally encountered, but it was judged that the
cost to conduct the experiment would be prohibitive if fewer malfunctions
were introduced in each vehicle. The high number of malfunctions in each
test vehicle did cause some problems with service organizations, (dis-
cussed in detail in paragraph 4.5.6) but were judged not to have greatly
influenced the experimental results.
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4.0 EXPERIMENTAL PROGRAM
This section describes the experimental program conducted by Scott
Research Laboratories, Inc.
4.1 VEHICLE INITIAL PREPARATION
Each vehicle received a major tune-up prior to the introduction of
malfunctions. The tune-up included replacement of sparkplugs, points,
condensers, distributor rotor, distributor cap, PCV valve, complete
diagnostic check and maintenance of the distributor assembly, new ignition
harness and air filter element. The complete inspection of all engine
parameters was accomplished as described in the following pages.
Extreme care was taken in preparing vehicles to eliminate
uncertainties in vehicle operating condition which might cause confound-
ing of the experimental results.
The following sixteen (16) items were inspected by a Scott mechanic
for deviation from specification or failure.
1. Basic timing
2. Idle rpm
3. Idle mixture
4. Dwell
5. Mi s f i re
a. wires
b. plugs
6. PCV valve
7. Air cleaner element
8. Vacuum hose leaks
9. NOV devices
X
10. Other special devices
11. Point opening variation
12. Mechanical advance
13. Vacuum advance
14. Manifold vacuum
15. Choke setting
16. Heat riser valve
The inspection sheet used for recording deviations is shown in Figure 4.1,
Engine Parameter Inspection Summary. All required repairs or adjustments
were performed, including inspection and maintenance of crankcase oil,
transmission fluid and cooling system, to put the vehicles in factory
specification operating condition. The vehicles were then ready for the
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2.
Engine Parameter Inspection
Performed By
SCOTT RESEARCH LABORATORIES, INC.
1. Vehicle Identification
1.1
1.2
1.3
1.4
1.5
Test No. 1 1 1A
Car No., 205
License No. ZZT 088
Inspected By JH
Date 6-24-71
Ignition System Inspection
2.1 Required Voltage, kv at 1500 rpm
2.2 Coil Available Voltage, kv at 1500 rpm
2.3 Spark Line (OK, NG)
2.4 Coil Oscillations (OK, NG)
2.'5 Point Opening Variation, degrees
2.6 Cci! Polarity (OK, NG)
2.7 Ignition Point Dwell, degrees
2.8 Condenser Oscillations (OK, NG)
2.9 Basic Ignition Timing, degrees
2.10 Total Advance at 2500 rpm, degrees
2.11 Mechanical Advance, at 2500 rpm, degrees
2.12 Vacuum Advance at 2500 rpm, degrees
Induction System
3.1 Idle Speed, rpm(Chrys. in Neutral) NJL Dr_
3.2 Manifold Vacuum, in. Hg.
3.3 Air Cleaner Angle, degrees
3.4 Float Level, inches*
3.5 Choke, Vacuum Kick, inches
3.6 Choke Vacuum Diaphragm (OK, NG, None)
3.7 Heat Riser Valve (None, Free, Frozen)
* On parking lot survey only
Figure 4.1 Engine Parameter Inspection Summary
3
5
7
8
9
10
11
13
m
16
18
20
Measurement
or Analysis
5-8
36
NG
NG
2
CK
35
OK
10 BTDC
50
28
22
kv
kv
o
0
o
o
0
o
Manufacturer's
Specification
12
15
17
19
21
27-32
5 BTDC
41-50 1/2
23-26 1/2
18-24
kv
kv
1
3
5
7
9
11
12
650
15
0
.081
OK
FREE
rpm
6
8
10
600
.081
El
*
rpm
10
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4.
5.
Emission Control
4.1 PCV Perf. at Idle, inches H2O**
4.2 Vacuum Leaks (Yes or No)
4.3 Idle rpm change (Leaks Eliminated)
4.4 NO Control Device (Ok, NG, None)
X
4.5 Timing Retard Mechanism (OK, NG, None)
13
15
16
17
Measurement
or Analysis
-.1
NO
NONE
NONE
o Air Pump Disconnected, Emissions
5.2 33. 5/30 MPH Cruise
o Plug Req:s Volt, kv
o Misfire Rate, %
o Air Cleaner Restriction, in H~O
o PCV Flow, inches
o Air Pump Disconnected, Emissions
Keymode Diagnostic Inspection
Dyno Load Set to 30 HP at 50 MPH
5.1 49/45 MPH Cruise
o Plug Req'd Volt, kv
o Misfire Rate, %
o Air Cleaner Restriction, in H~O
o PCV Flow, inches
Completed By
rpm
1
2
3
4
7-9
0
.2
.40
kv
%
Manufacturer's
Specification
Completed By
5.3 Idle (in Drive)
o Plug Req'd Volt, kv
o Misfire Rate, %
0 Air Pump Disconnected, Emissions
9
10
12-15
0
npleted By
kv
% (REJ)
REMARKS:
.High point resistance
** Vacuum is minus (-), and Pressure is plus (+)
Figure 4.1 Engine Parameter Inspection Summary (Cont'd)
11
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introduction of malfunctions called for in the experimental program design.
4.2 PARAMETER MALFUNCTION METHODS
All parameter deviations from manufacturer's specifications are
shown in Figure 3.1. Deviations of idle rpm, idle CO, and timing advance
were adjusted using standard shop ignition analyzers and standard NDIR
instrumentation for idle CO settings. Methods for achieving all other
malfunctions are shown in Figure 4.2. Confounding malfunctions were
introduced in the two emission fleet vehicles to create the possibility
of errors of omission and commission by the service organizations. The
confounding parameters were a bent push rod (which simulated valve failure),
which could be confused with misfire, and a high carburetor float level
which would produce a high CO reading under light and heavy load condi-
tions, and could be confused with a malfunctioning PCV valve or restricted
air cleaner element.
The measure of air cleaner deviation from specification used on this
program was the volume % CO increase over that produced using a baseline
air cleaner element measured at 50 mph road load. If an increase of
2.5% CO at 50 mph road load could not be obtained before a maximum AC
air cleaner tester reading of 180 was observed, the restriction was
limited to that which produced this maximum indicated value. This is the
same procedure employed on the orthogonal experiments for indicating the
degree of element restriction. Idle CO was set for each experiment using
standard NDIR instrumentation.
After the vehicle was malfunctioned for the first time, it was run on
a Clayton key mode cycle to establish an emission baseline. This provided
a baseline from which to detect incorrect maintenance or unwanted car-
buretor repairs. Modified, Clayton key mode truth charts were also prepared
from these data.
4.3 SERVICE ORGANIZATION SELECTION
Three classes of service organizations were selected for the experi-
ment: franchised dealerships of major American automobile manufacturers,
independent garages, and major oil company service stations. The three
12
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Figure 4.2
Malfunction Methods
NOV Control
A
Transmission controlled spark relay points bent open,
shorted thermal switch, transmission controlled spark fuse
blown, speed switch lead disconnected.
Spark Plug Wire
Hole in insulation near ground, removed conductor from
insulation, wire disconnected.
Spark Plug
Tight gap, carbon resistor removed from plug, center
electrode removed.
Air Cleaner
Restricted with shellac, "Dressed up" with oil film and
dust to look realistic.
PCV Valve
Plugged with devcon, "Dressed up" with oil and dust to look
realistic.
Heat Riser
Wired Open, bind shaft with soft tubing or wire.
13
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classes were chosen to evaluate their relative performance capabilities.
The experiment was conducted in two geographic locations: San
Bernardino and Riverside, California. Selection of repair agencies were
made as follows: A list of organizations which were registered as Calif-
ornia Class A service organizations was obtained from the California High-
way Patrol Office, (the Agency responsible for issuing license for
Class A service organizations and policing their performance). Service
organizations were then selected at random as candidates for participating
in the program. The method of soliciting participation is discussed in
paragraph 4.4.
4.4 INTERFACE WITH SERVICE ORGANIZATIONS
A personal contact was made with service organizations selected as
candidates to determine their interest in performing maintenance work
for Scott and their ability to process the vehicles in a timely fashion.
Since Scott's involvement in air pollution research is known locally, the
service organizations were informed that a group of vehicles used on
several emission test programs required maintenance in order to qualify
for a California Smog Certificate. It was stated that Scott had made the
inspections which indicated the need for maintenance but did not have
sufficient personnel to perform the maintenance. Scott also was not
licensed to issue Smog Certificates. This approach minimized the possi-
bility that the service organizations would infer that the California
Highway Patrol was using this method to audit their performance. When
this question occasionally arose, Scott replied, as was true, that the
Highway Patrol was not involved in any way with this test program.
The initial plan was to send both the parameter inspection vehicles
and the emission inspection vehicles to the same set of dealerships for
repair. As the program developed, it became obvious that such a plan
would cause too much discussion with service organizations, since the
instructions were different for each fleet of five (5) vehicles. This
part of the plan was therefore changed so that only parameter vehicles
or emission vehicles were sent to a single service organization. The
problems encountered are discussed more fully in Section 5.4.
14
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4.5 TEST PROGRAM DESCRIPTION
4.5.1 Test Plan
The test plan called for two groups of vehicles, a five (5) vehicle
parameter inspection fleet and a five (5) vehicle emission inspection
fleet. Each fleet was to be submitted to five (5) dealerships, five (5)
service stations and five (5) independent garages in the San Bernardino
area and in the Los Angeles area. This would have resulted in a total of
one hundred and fifty (150) tests on the two fleets of vehicles in each
geographical area for a total of three hundred (300) tests.
This goal was not achieved for the following reasons:
a) The time required for vehicle processing by the service
organizations was longer than planned and the total time
required to complete the program would have extended beyond
the contract period.
b) The combination of higher repair costs than anticipated,
and the increased cost to lease vehicles for a longer
performance period, resulted in higher program costs than
had been planned.
c) A cost trade-off between conducting the tests in Los Angeles
or Riverside showed that more data could be obtained by
selecting Riverside as the second geographical location to
be investigated. The same cost study showed that the number
of tests in Riverside needed to be set at thirty (30)
emission fleet tests and sixty (60) parameter fleet tests
in order to meet contract cost constraints. Thus, ninety (90)
tests were conducted in Riverside instead of the originally
planned one hundred and fifty (150) tests in Los Angeles
as the second geographic location. The lower number of
tests, however, were sufficient to determine if geographical
location had a significant effect on maintenance accuracy
and cost.
4.5.2 Vehicle Set-up and Check After Service Organization
Maintenance
The ten test vehicles were precisely maladjusted to the degree
specified in Table 3.1 prior to submittal to each service organization.
15
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Also, each vehicle received the same set of malfunctions each time it
was submitted to a service organization.
After a vehicle was malfunctioned in preparation for submittal to
the first repair agency, it was tested on the Clayton Key Mode Cycle to
establish the emission baseline and to record the "standard" malfunction
deviations to be used throughout the test program. Figure 4.3, Service
Organization Evaluation Inspection Sheet, shows an example of the Scott
inspection sheet used to record the vehicle malfunction settings made
before submitting a vehicle for maintenance and the record of settings
made by the service organization. This inspection sheet was used to
insure consistent malfunction settings for each vehicle by Scott mechanics
as well as to record settings and repairs made by each service organization.
After test vehicles were returned to Scott, they were inspected by
Scott mechanics to determine how effectively the service organization had
performed. The Service Organization Evaluation Inspection Sheet, Figure
4.3, illustrates how garage performance was evaluated.
The "malfunction specification" entries are the required
settings and malfunctions to be made by Scott prior to
submittal to the service organization.
The "settings achieved" entries are the actual settings
made by Scott prior to submitting the car to the service
organization.
"Settings after repair" are the engine parameter settings
or malfunctions determined by Scott after the vehicle was
returned by the service organization. Under the headline
"comments", if the Scott mechanic detected evidence that
an item such as the carburetor had been overhauled, this
note would flag the project engineer to check the repair
invoice, and if indeed there was documented carburetor
repair kit costs and labor, the vehicle would be returned
and reset to the "malfunction specification" condition,
as described in paragraph 4.5.5.
t If no unwarranted work was performed, the vehicle was reset
to the required "malfunction specification", condition in
preparation for submittal to another service organization.
All malfunctioned vehicles were sent to service organizations with a
request to perform the maintenance necessary to issue a California Smog
Certificate. The specific data accompanying the parameter inspection and
emission inspection vehicles are described in paragraph 4.5.2. In addition
16
-------
Figure 4.3
Service Organization Evaluation
Inspection Sheet
Car Number and Description
1971 Ford LTD
Service Organization Welstand's Hld-NUe Auto
Idle
Timing
NO.
% CO rpm Basic Control
Misfire
Plug Spark
Wire Pluq
Induction
System
Air Cleaner
% CO
PCV
Choke
System
Heat
Riser
Blade
Setting
Malfunction
Specification
4.4
575
16 BTOC
6% \ 0.2%
OK
Free
.19,in.
Setting
Achieved
4.4 575 16
[__ _ L
180°
OK Free .19 in.
Setting
After Repair
I 0.7 I 625 | 6 | I I 0 I
I OK I Free I .19 In. I
Inspected by
and Date
Doe:
/)
tt
m rs
-------
to the specific instructions supplied for both fleets limitations were
imposed on the repair organizations requiring prior approval for
major work such as valve jobs and carburetor rebuilding. This is con-
sistent with normal practice in California where individuals request
the opportunity to review the cost of major repairs prior to initiating
the work. If an organization reported that they could not issue a smog
certificate without major work, Scott recalled the vehicle, with the
explanation that customer approval was required for maintenance of that
magnitude. If a repair invoice indicated that non-required work had
been performed on a carburetor and an emission upset was produced, the
carburetor was returned as nearly as possible to its original state. The
original keymode inspection was then repeated to establish a new emission
baseline.
4.5.3 Parameter Inspection Fleet
A simple instruction sheet, Figure 4.4 Typical Malfunctions Which
Cause High Exhaust Emissions,was given to the service organization with
vehicles of the parameter inspection fleet along with a request to perform
the repairs necessary to provide a smog certificate. As can be noted,
the instructions were very general. They included the written approval
clause, and requested that the service organization record the settings
used for adjusting idle speed, idle mixture, basic timing and choke kick.
These data were requested to determine if the mechanic making the repair
had used correct manufacturer's specifications.
4.5.4 Emission Inspection Fleet
The emission inspection vehicles were given to service organizations
together with instructions similar to the Clayton Truth Charts, Figures
4.5 through 4.12. Only those truth charts applicable to the emission
tests failed by the vehicle were sent with the vehicle. It was presumed
that this practice would be followed in an actual mandatory program of
inspection and maintenance which employed a mode emission inspection.
As with the parameter inspection vehicles, major repairs were not
permitted without prior approval and requests for conducting major repair
were handled in the same manner. Again it was requested that the service
organization record the settings used to adjust engine parameters. The
same control sheet, Figure 4.3 was used to record vehicle settings after
repair.
18
-------
Figure 4.4
TYPICAL MALFUNCTIONS
WHICH CAUSE HIGH EXHAUST EMISSIONS
Please check and set to Factory Specifications or Replace Parts as
Necessary.
Please Record Setting Used
1. Idle Speed
2. Idle Mixture
3. Basic Timing
4. Choke Blade ^'
5. Ignition Misfire
6. Air Cleaner
7. PCV Valve
8. Exhaust Heat Valve
9. Oxides of Nitrogen /?\
(NOV Control) System ( '
A
NOTE: Written Approval will be Required for All Major Work Such As:
1. New carburetors or "boil outs"
2. New distributors
3. Head & intake gaskets
4. Valve grinding
5. Engine overhaul
^ 'Choke Blade Nomenclature
1. Vacuum kick or break
2. Choke valve pull-down
3. Initial choke opening
4. Intermediate choke rod - piston choke
NO Control Nomenclature
A
1. A.M.C. and G.M. - Transmission Controller Spark (TCS)
2. Chrysler Corp. - NOY System
A
19
-------
Figure 4.5
TRUTH CHART #1
High HC @ Idle Only
Usual Causes
1. Vacuum leaks
2. Idle too lean or jets not balanced
3. Timing advanced grossly
4. Intermittent misfire
5. Low idle speed
6. Bad exhaust valves
Authorized Repairs if Out of Specification
1. Check dwell, timing, idle speed, and mixture
2. Check spark plug gaps
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
20
-------
Figure 4.6
TRUTH CHART #2
High HC @ Idle and at Low Cruise
Usual Causes
1. Vacuum leaks
2. Idle too lean or idle jets not balanced
3. Timing advanced grossly
4. Bad exhaust valves
5. Excessively rich mixture (high CO)
6. Ignition misfire
Authorized Repairs if out of Specification
1. Check dwell, timing, idle speed and mixture
2. Make oscilloscope checkout
3. Check spark plug gaps
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
21
-------
Figure 4.7
TRUTH CHART #3
High HC @ Low and/or High Cruise
Usual Causes
1. Ignition misfire, usually in secondary
2. Faulty distributor, causing over advance
Authorized Repairs if out of Specification
1. Check dwell and timing
2. Use an oscilloscope to check
a. faulty spark plug
b. faulty ignition cable
c. loose primary wiring
d. point arcing
e. cross fire due to cracked or carbon tracked cap or rotor
f. corrosion in distributor cap or wires not seated
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
22
-------
Figure 4.8
TRUTH CHART #4
High HC in all Modes
Usual Causes
1. Disconnected ignition wire
2. Completely fouled spark plug
3. Secondary wiring defective
4. Faulty distributor
5. Bad valves
Authorized Repairs if out of Specification
1. Check dwell and timing
2. Use an oscilloscope to check
a. faulty spark plug
b. faulty ignition cable
c. loose primary wiring
d. point arcing
e. cross fire due to cracked or carbon tracked cap or rotor
f. corrosion in distributor cap or wires not seated
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
23
-------
Figure 4.9
TRUTH CHART #5
High CO @ Idle
Usual Causes
1. Maladjusted idle jets
2. Carburetor leaking internally
Authorized Repairs if out of Specification
1. Adjust carburetor mixture and speed
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
24
-------
Figure 4.10
TRUTH CHART #6
High CO @ Idle and at Low Cruise
Usual Causes
1. Severely maladjusted idle jets
2. Restricted PCV
3. Choke blade partially closed
4. High float level
5. Internal carburetor leaks
Authorized Repairs if out of Specification
1. Check PCV system
2. Check choke blade
3. Set dwell, timing, idle speed and mixture
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
25
-------
Figure 4.11
TRUTH CHART #7
High CO @ Low Cruise and/or High Cruise
Usual Causes
1. Malfunction in carburetor main metering system
2. High float level
3. PCV restriction
4. Air cleaner restriction
5. Choke blade partially closed
Authorized Repairs if out of Specification
1. Check PCV system
2. Check air cleaner
3. Check choke blade
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE
BASIC TIMING
26
-------
Figure 4.12
TRUTH CHART #8
High CO in all Modes of Operation
Usual Causes
1. A substantial internal leak in carburetor
2. A combination of malfunctioning carburetor main system and
maladjusted idle jets
Authorized Repairs if out of Specification
1. Check for air cleaner restriction
2. Check choke plate for being stuck partially closed
3. Set ignition timing, dwell, idle speed and mixture
PLEASE RECORD SETTING USED IF ANY OF
THE FOLLOWING ARE ADJUSTED
IDLE SPEED
IDLE MIXTURE_
BASIC TIMING
27
-------
4.5.5 Service Organization Maintenance Evaluation
Each service organization was requested to provide a detailed repair
invoice indicating parts and labor. The Service Organization Evaluation
Inspection Sheet, Figure 4.4 repair invoices, and the manufacturer's
baseline parameter data were collected by the project engineer for each
test of each vehicle. All pertinent data were tabulated by vehicle number,
test number and service organization type and location. These data were
analyzed, as discussed in Experimental Results (Section 5), to determine
maintenance effectiveness, i.e., how many malfunctions were detected and
properly maintained, and the maintenance cost. An attempt was also made
to determine the extent of unnecessary maintenance performed on each
vehicle. This was done by reviewing the repair invoices to find unneces-
sary parts or labor descriptions and the mechanics notes on the inspection
form, Figure 4.3.
All organizations did not provide detailed cost invoices showing all
parts and labor. Thus the estimates of unnecessary maintenance were
subject to errors in judgement when data were not provided. This is
discussed in more detail in Section 5.0, Experimental Results.
4.5.6 Experimental Difficulties
4.5.6.1 Typical Difficulties
Several types of experimental difficulties were encountered during
the test program.
a) Malfunction Selection
During approximately the first two weeks of the program, the malfunction
matrix (Figure 3.la) contained malfunctions which were not completely
consistent with vehicle mileage or age, (particularly the 1970 and 1971
models). In the initial matrix, PCV valves were failed on some late model
cars when submitted to the repair agencies. The frequency of misfire
and NO control component failure also were not consistent with service
A
organization experience. This resulted in calls from the service organi-
zations concerning the malfunctions. In some cases, the caller asked
whether the California Highway Patrol was using this method to audit
their work. In other instances, the questions indicated disbelief that
specific malfunctions were natural.
28
-------
Scott and TRW reviewed the malfunction matrix and either eliminated
those malfunctions which had been questioned most frequently or revised
them to represent natural malfunctions more closely. Enough malfunctions
per vehicle were kept to produce sufficient data for subsequent statis-
tical analyses.
The revised malfunction matrix, Figure 3.1, and the explanation that
the vehicles had been used on a variety of experimental programs which
might have resulted in a higher incidence of failures, reduced the tele-
phone calls primarily to questions concerning the need for major mainte-
nance. Since the questionable malfunctions were eliminated early in the
program, the results of the experiment are considered to be valid.
b) Requests For Major Overhaul Authority
Occasionally, a service organization would request permission to
perform a valve grinding job (caused by the indicated valve failure due
to the bent push rod), or to rebuild or replace a carburetor. Usually,
the request was accompanied by the statement that unless the work was
authorized, the service organization could not issue a California Smog
Certificate. In these instances Scott recalled the vehicle with the
explanation that the Sponsor's permission would be required to authorize
major repair.
Since Scott could not determine what maintenance had been done prior
to the recall, these tests were not used in the evaluation of the main-
tenance effectivenss of service organizations.
4.5.6.2 Experimental Difficulty Effects on Program
Even though experimental difficulties did occur, the kinds of
difficulties encountered in the experiment would tend to result in better
rather than less effective maintenance performance by the service organi-
zations. The experiment therefore may overestimate the effectiveness
with which maintenance is performed by the spectrum of service organiza-
tions studied.
29
-------
5.0 RESULTS
The analysis of the data acquired in the previously described test
program was conducted in two steps:
t An engineering evaluation of the data was performed to
select a procedure for systematically analyzing its details.
t Statistical analyses were done to separate real effects from
experimental variability.
These two steps are described in detail in the following discussion.
5.1 OVERVIEW
An examination of the data indicated that the performance effectiveness
of all the types of service organizations tested was marginal to poor for
vehicles in both the parameter inspection and emission inspection fleets.
A top level summary of the fraction of malfunctions and maladjustments
corrected by each class of service organization is presented in Table 5.1.
The data shown were obtained by pooling test results obtained in the San
Bernardino and Riverside areas. This table shows that up to 52 percent
of the emissions related malfunctions and maladjustments remained uncorrected
following maintenance. Successful maintenance performance ranged from 48
to 68 percent. These data further suggest that some types of service
organizations perform better than others. This point will be explored in
a following section of this report.
Table 5.2 which shows the range of detection and the range of success-
ful repair of engine malfunctions indicates that the detection of a mal-
function does not guarantee a successful repair. Again the data of this
table were obtained by pooling the San Bernardino and Riverside test
results. As shown, the detection rate for an idle fuel-to-air ratio
maladjustment ranged from 55 percent to 100 percent while the ability of
the service organizations to adjust this parameter to within +1 percent
of manufacturers specifications ranged from complete failure to a maximum
of 52 percent. Similar discrepancies between maladjustment detection and
repair can also be seen for idle rpm, timing and choke kick. Detection
30
-------
Table 5.1
Malfunctions Detected and Corrected
Independent
Garages
Emission Parameter
Vehicles Vehicles
Dealerships
Emission Parameter
Vehicles Vehicles
Service Stations
Emission Parameter
Vehicles Vehicles
Total
Malfunctions 133
Submitted
Malfunctions
Found 73
And Corrected
Malfunctions
Not Corrected 60
242
122
120
134
92
42
239
120
119
140
85
55
243
119
124
Malfunctions
Found
And Corrected
54%
50%
68%
50%
60%
48%
31
-------
Table 5.2
Range of Detection or Repair
of Malfunctioned Parameters for
All Vehicles Under All Experimental Conditions
Parameter
Idle CO
Idle RPM
Basic Timing
NO Control Device
Detection,
55 to 100
67 to 100
50 to 89
12 to 41
Spark Plug Wire Misfire 25 to 100
Spark Plug Misfire
Air Cleaner
PCV Valve
Heat Riser Valve
Choke Kick
50 to 96
67 to 86
50 to 90
15 to 67
27 to 37
Repair, %
0 to 52
45 to 73
33 to 78
12 to 41
25 to 100
50 to 96
67 to 86
50 to 90
15 to 67
15 to 18
Repair Type
Adjustment
Parts Replacement
Parts Repair or Re-
placement
Parts Replacement
Parts Repair
Adjustment
32
-------
and repair percentages were identical for the other malfunctions studied
because the repair generally entailed the replacement of a faulty part
rather than an adjustment to specification.
5.2 IDLE ADJUSTMENT REPAIR ACCURACY
The three engine idle adjustments, idle CO, idle rpm and basic
timing are continuous variables in that they can be set to an infinite
number of values. The settings achieved during maintenance are influenced
by equipment accuracy, human error, as well as errors in specification
values and procedures. Table 5.3 shows the percent of maintained vehicles
which were set within a given tolerance band about specification.
5.2.1 Idle CO
Idle CO adjustment accuracy is seen to be generally poorer
than idle rpm and timing. There are several possible reasons for this
poorer performance: 1) many service organizations use conventional fuel-
to-air ratio meters instead of exhaust CO analyzers. This can result in
both random and bias errors relative to values measured with the referee
instrument. 2) idle CO can vary depending upon engine operating history
immediately prior to measuring CO level. Referee measurements were made
after the vehicles were driven back from the service organization and were
not made following an extended period of engine operation at idle speed.
3) different sources may have been used to obtain vehicle adjustment
specifications. For example, the certificate of compliance instructions
specify a fuel-to-air ratio mixture between 13.5:1 and 14.5:1 which is on
the rich side of most manufacturers' specifications.
5.2.2 Idle rpm and Timing
Although the maintenance effectiveness for idle rpm and basic
timing was somewhat higher than for idle CO, it was still poor in many
cases. These two adjustments are not as sensitive to prior vehicle operat-
ing conditions as idle CO. There are several possible reasons however for
the variability found in their adjustment accuracy: 1) out of calibration
tachometers; 2) inadequate or inconsistently applied procedures; and 3)
obsolete, incorrect or misinterpreted tune-up specifications.
33
-------
Table 5.3
Repair Accuracy
(% of Vehicles Within Specification Tolerance Limits)
Independent
Dealerships
Emission Parameter Emission Parameter
Vehicle Vehicle Vehicle Vehicle
Service Stations
Emission Parameter
Vehicle Vehicle
1
13
FH V*
td cd
co c
u
0)
PP
CD
H
(0
&
^
H
Pi
Q
rl.
13
PH t_|
cd cd
co d
^_i
0)
w
cu
H
to
CD
£>
rl
pi
o
c
rl
""O
d t-i
cd cd
co C
$_J
0)
PP
cu
13
H
CO
cu
^
H
O
H
rrj
C! M
cd cd
J_l
cu
PP
cu
H
CO
0)
^
H
Pi
o
H
13
cd cd
co C
^_l
0)
PP
0)
H
to
0)
>
H
Pi
g
H
13
cd cd
CO C
}_l
0)
PP
0)
H
CO
CD
>
H
Idle CO (1) 26% 13% 50% 44% 43% 63% 50% 60%
Idle RPM (2) 50% 80% 71% 65% 54% 67% 68% 53%
Basic Timing(3) 63% 44% 58% 70% 70% 80% 76% 68%
37% 13% 45% 31%
60% 33% 44% 65%
56% 70% 52% 45%
5" 7
to
o
(1) Within 1% of Factory Specification
(2) Within +50 rpm for Factory Specification
(3) Within 2° of Factory Specification
34
-------
As described previously, service organizations were requested to
record the specifications used for setting idle CO, rpm and timing to
determine if the proper specifications were used. There is an indica-
tion that some service organizations may not have used proper specifica-
tions for making these adjustments. Table 5.4 shows the percent of times
the service organizations achieved the timing and rpm settings they defined
as specification values as compared to the standard specifications used
for the program. The fact that service organizations frequently achieved
adjustments closer to their reported specification values than to the
referee values is not statistically conclusive, but is indicative of
somewhat better performance than otherwise measured.
Table 5.4 also shows another interesting fact. Vehicles submitted
to service organizations with their timing (vehicle #2 and 3) and rpm
(vehicles #1, 4, 5, 6, 7 and 8) adjustments within specification were
frequently returned out of specification. The raw data, Appendix A,
indicate that idle rpm was generally set lower than specification and
that basic timing was more often set advanced of the specification value
than in a retarded condition. Because idle speed specifications for older
vehicles are generally slower than for new vehicles the data may indicate
that mechanics use their past experience in setting idle rpm and do not
refer to new specifications. Dealerships may have performed better in
making idle CO and idle rpm adjustments because their mechanics
received more training than those of other service organizations in
adjusting emissions related tune-up parameters.
It is noted that a possible confounding influence on this experiment
may have been introduced by requesting that the service organizations pro-
vide a smog certificate for each car repaired. The California Highway
Patrol Handbook for Installation and Inspection Stations under which the
smog certificate is issued provides specific tolerance limits on timing
and idle speed deviations from manufacturer's specifications. These
instructions allow timing deviations of +3° from manufacturer's specifica-
tions while +2° was used as a performance standard in this study. Further,
the California Highway Patrol Handbook allows an idle speed deviation of
+100 rpm or -25 rpm from specifications while +_50 rpm was used on this
program. Because the service organizations tested would certainly have
35
-------
--de 5 4
VARIATION OF REPAIR PERCENTAGE BASED UPON DIFFERENT REFERENCE SPECIFICATIONS
co
01
CAR
NO.
1
2
3
4
5
6
7
8
9
10
BASIC TIMING :
TOTAL
NO.**
19
12
17
16
13
26
25
25
26
23
ADJUSTMENT TO SPEC.
GARAGE SPEC.
NO.
12
9
16
12
8
15
22
13
18
15
%
63.2*
75.0
94.1
75.0*
61.5*
57.7*
88.0*
69.2*
69.3*
65.2*
SRL SPEC.
%
52.4*
70.0
100.0
47.6*
33.3*
61.5*
77.8*
40.7*
66.7*
65.4*
, _______ . ______,,_---- .--5
IDLE RPM '.
TOTAL
NO. **
18
11
19
16
14
25
26
26
27
23
ADJUSTMENT TO SPEC.
GARAGE SPEC.
NO.
14
5
10
7
7
11
15
18
21
15
%
77.8 ~
45.5*
52.6*
43.8
50.0
44.0
57.8
69.2.
77.8*
65.2*
SRL SPEC.
%
66.6
45.0*
66.7*
47.7
55.6
30.8
63.0
70.4
70.4*
73.1*
*Parameters were malfunctioned when submitted to service organization.
**Total number of vehicle submittals to Service Organizations with timing and RPM adjusted
outside of specification limits (+2° timing +50 RPM)
-------
had access to this handbook, it is possible that their performance was
influenced by its less restrictive tolerance bands on engine adjust-
ments.
5.3 COMPONENT REPAIR ACCURACY
Some of the simulated malfunctions involve components which either
operate satisfactorily or are failed. These malfunctions therefore are
considered to be discontinuous or bimodal variables. If this class of
malfunction is detected then it generally can be completely corrected
by parts repair or replacement. Table 5.5 shows the percentage of
malfunctions within this class which were detected and repaired. The
indicated maintenance effectiveness for spark plug misfire (90%), plug
wire misfire (79%), PCV valve failures (77%), and excessive air cleaner
plugging (74%) was fairly good while that for failed heat riser valves
(36%) and NO control device failure (21%) was poor.
A
The choke blade relief sitting is the only continuous variable
studied other than the idle adjustments previously discussed. The
service organizations tested showed very poor (17%) ability to detect
and repair this maladjustment which has a pronounced effect upon engine
cold start emissions.
There are several possible reasons for the observed variation in
maintenance effectiveness. Diagnosis of misfire due to malfunctioned
spark plugs or the ignition wire harness (spark plug wire) is a common
procedure. PCV valves have been installed in California vehicles for
several years and most mechanics are familiar with this device. Air
cleaners can be visually inspected to see if they "look dirty." All
of these components are usually carried in inventory and are readily
replaceable. Thus, the high frequency of detection and repair may be a
matter of familiarity with the diagnostic and repair procedures. Examina-
tion of the test data, Appendix A, shows that the frequency of diagnosis
and repair of the PCV valve was highest for the older vehicles. A
possible reason is that mechanics may expect to find a faulty PCV valve
in older vehicles and their experience indicates that newer vehicles do
not usually have faulty PCV valves.
37
-------
Table 5.5
Repair Accuracy for Malfunctions
Requiring Repair or Replacement
Independents
Dealerships
Service Station
CO
oo
Malfunction
NO Device
X
Misfire (Plug Wire)
Misfire (Spark Plug)
A/C
PCV Valve
Heat Riser
Choke Blade Setting
%
Emission
0
92
100
64
88
42
__
Found
Parameter
19
44
88
88
76
23
6
%
Emission
57
85
100
78
85
71
Found
Parameter
34
88
100
61
55
33
22
%
Emission
14
100
71
85
100
85
Found
Parameter
7
44
83
66
66
16
22
Total
% Found
21
79
90
74
77
36
17
-------
The NO control device, however, is a relatively new component or
A
system. The poor maintenance effectiveness measured is most likely due
to a lack of familiarity with this new system. Dealership performance,
although low, was better than either that of independent garages or
service stations, probably because of their greater familiarity with new
vehicle accessories.
Poorest maintenance performance was observed in the setting of
carburetor choke blade kick angle. This may be caused by the fact that
the choke blade is open during hot engine operation and the kick angle
is not routinely checked unless either there is a starting complaint or
the carburetor is overhauled. It should again be noted that specific
approval was required before a carburetor overhaul could be performed
on the test vehicles. This restriction may have discouraged the investi-
gation of the choke blade relief setting.
5.4 REPAIR COSTS
Service organizations were requested to provide both parts and labor
cost breakdowns for each repair order. These data however were obtained
only in part. Many repair bills showed parts costs and labor costs, but
did not provide a detailed separation of labor associated with each
repair. Usually, the labor was billed as a lump sum. A precise analysis
of the various cost elements therefore was not possible. An attempt was
made however to characterize average costs and to identify repairs leading
to excessive costs.
5.4.1 Average Repair Costs
Table 5.6 is a summary of the average costs grouped by inspec-
tion process, service organization, and city. It can be seen that average
costs were highest for dealerships in both cities and were highest in
Riverside for all types of service organizations. There was no significant
difference in cost associated with instructions reflecting the two basic
types of vehicle inspection strategies. Independent garages and service
station costs exhibited differences between the two cities. Differing
combinations of malfunctions certainly account for some of this. Difficulty
in conducting the maintenance because of parts availability and malfunction
accessibility varies with each vehicle and also may account for some part of
the performance differences.
39
-------
Table 5.6
Average Repair Costs ($)
Average Cost to
Repair Malfunctions;
Riverside
San Bernardino
Independent
Garages
Emission
Vehicles
14.87
13.99
Parameter
Vehicles
36.99
19.95
Dealerships
Emission
Vehicles
33.68
26.57
Parameter
Vehicles
28.97
27.85
Service Stations
Emission
Vehicles
29.49
16.10
Parameter
Vehicles
11.07
18.66
Highest Cost to
Repair Malfunctions;
Riverside
San Bernardino
19.85
33.95
71.15
49.08
38.74
57.61
81.33
42.39
46.38
31.89
27.46
26.32
Lowest Cost to
Repair Malfunctions:
Riverside
San Bernardino
7.50
5.00
14.51
7.00
11.95
1.42
9.00
7.29
11.00
4.60
5.50
6.50
-------
5.4.2 Unnecessary Repairs
An estimate of unnecessary repairs was made from those inv,,;...
which provided a separation of costs. The true magnitude of unnecessary
repair costs is still speculative because complete parts and labor break-
downs could not be obtained from all service organizations without com
promising the blind nature of the experiment. The dollar values shown in
Table 5.7 for unnecessary repairs reflects identifiable cost of unnecessa
parts only. Even on this basis the average unnecessary repair cost in soi;
service organizations exceeded $9 per car with one bill judged to contain
$36 in unnecessary parts. If a one to one ratio is a reasonable estimate
of labor to material costs then the cost of unnecessary repairs would L,
double those shown in Table 5.7.
The higher costs shown for unnecessary repairs made by dealerships
is believed to reflect the fact that dealership invoices provided a more
complete list of parts and hence provided a better means for identifying
unnecessary repairs. Unnecessary repair costs in the other two types of
service organizations therefore are probably underestimated.
A Summary of Unnecessary Repairs Performed, Table 5.8, reflects tr;
estimated number of such repairs and identifies the types of repair -..-..
sidered unnecessary. The higher average cost of repair in Riverside ;j, t
to be highly correlated to excessive repair.
5.4.3 Vehicle Process Time
The average length of time required by service or-ganizaiKr.:;
to repair the test vehicles was 1.4 days. The importance of this inTi.,-.,
tion is that it is a measure of what mandatory inspection and ruaUitessjK::
programs will cost the public either in inconvenience or in vehicie
rental costs when service organizations do not provide loan vehicles
41
-------
Table 5.7
Summary of Excessive Repair Costs
(Dollar Cost of Unrequired Parts Replacement)
Average Unnecessary
Repair Costs:
Independent
Garages
Emission Parameter
Vehicles Vehicles
Dealerships Service Stations
Emission Parameter Emission
Vehicles Vehicles Vehicles
Parameter
Vehicles
Riverside
San Bernardino
,45
,39
9.01
1.66
9.46
3.70
4.43
4.26
9.53
1.85
.88
4.08
ro
Highest Unnecessary
Repair Costs:
Riverside
San Bernardino
4.05
6.12
26.55
1.66
36.81
19.11
21.53
27.04
24.23
28.70
7.14
17.95
-------
Table 5.8
Summary of Number of Unnecessary Repairs Performed
Independents
Dealerships
Emission
Vehicles
Number of Unnecessary
Repairs Performed;
Riverside
San Bernardino
1
2
Parameter
Vehicles
28
9
Emission
Vehicles
22
18
Parameter
Vehicles
23
21
Service Stations
Emission
Vehicles
Parameter
Vehicles
15
11
7
18
Number of Unnecessary
Repairs Performed Per
Vehicle Processed;
Riverside
San Bernardino
.11
.08
1.40
.38
2.20
.78
1.21
.84
1.50
.44
.35
.72
CO
TYPICAL UNNECESSARY REPAIRS PERFORMED
1. Complete set of spark plugs or plug wires installed when only one was malfunctioning.
2. New PCV valve when not needed.
3. New air cleaner when not needed.
4. New vacuum hose when not needed.
5. New NOX switch and control device when malfunctioned device could easily be repaired.
6. Gas or oil additives.
7. Tune-up components installed when not needed. (Points, condenser, rotor distributor cap).
8. Fuel filter
9. Vacuum advance unit; and vacuum brake.
-------
5.5 STATISTICAL ANALYSIS
Statistical analyses were made of the experimental data to determine
the influence on maintenance performance effectiveness of:
t Instruction given to the service organizations
(parameter inspection or emission inspection data)
Class of service organization
Service organization location
t Vehicle and control device characteristics.
The deviation of idle CO, idle rpm and basic timing adjustments from
specification as measured by Scott following repair was used as the
dependent variable when analyzing performance. The total repair cost
was used in making cost comparisons. With continuous variables such as
idle CO, idle rpm, timing and cost where the number of measurements made
at each experimental combination was not equal, an unweighted analysis
of variance was employed.
For the other malfunctioned parameters, the category identification
"found" or "not found" was the dependent variable. (For choke kick, the
category identification "found and repaired" or "not repaired" was the
dependent variable.) The number of malfunctions of a given type found
and the number of malfunctions of tltat type not found was obtained for
each city, each service organization type and for each instructional
2
level. A X statistic with Yates Correction for continuity was used when
there were only two levels of the dependent variable.
Table 5.9 presents the results of these analyses and shows the confi-
dence level (Q >0.9) associated with the F statistic obtained for each
treatment main effect on each dependent variable. This table indicates
that for certain malfunctioned parameters, there was a significant
influence of city, service organization type, inspection instructions and
vehicle. As can be seen, vehicle effects are most predominant. The
effects of service instruction are significant for idle CO, heat riser,
and plug wire misfire. However, the partitioning of test vehicles by
service instruction makes conclusions about service instruction effects
tentative, at best. The partitioning of vehicles by service instructions
does not, of course, affect conclusions about city or service organization
effects. It should also be noted that the experiment is not symmetrical
44
-------
Table 5.9
Results of Analyses of Variance Using
the Complete Data Set
(Confidence Levels >90)
Parameter
Idle CO
Idle RPM
Basic Timing
Cost
NCL. Control
Cities
Effect (2)
.90
-
-
.95
_
Service
Organization
Type Effect (3)
.95
-
-
.99
.99
Service
Instruction
Effect (2)
.95
-
-
-
_
Vehicle
Effect (10)
.99
.99
.99
.95
.99
Misfire
(Plugwire)
Misfire
(Spark Plug)
Air Cleaner
P.C.V. Valve
Heat Riser
Blade Setting
.99
.90
.99
.98
45
-------
by the type of service instruction (i.e., similar model/year vehicles in
each group did not have identical malfunctions) or city (i.e., sample sets
of the two cities were different). The effect of non-symmetric sample
sets between cities was accounted for by the method of analysis, however,
conclusions regarding the type of service instruction are questionable.
The simultaneous occurrence of a significant vehicle effect and
service instruction effect on idle CO makes the significant instruction
effect obtained on idle CO questionable. Also, because the heat riser was
malfunctioned in one older car in the emission inspection fleet, and in
two newer cars in the parameter inspection fleet, it is likely that the
significant instructional effect obtained should be attributed to a
vehicle phenomenon. On the other hand, while there is vehicle confound-
ing associated with the significant instructional effect on plug wire
misfire, there is no obvious bias influencing the malfunction distribu-
tions of the two instructional groups. Therefore, we may tentatively
conclude that the effect of service instruction is real for plug wire
misfire.
5.5.1 Idle CO
The deviation of idle CO emission level after-repair relative
to the established idle CO specification value was used as the dependent
variable for this analysis. An unweighted means analysis of variance
showed significant effects for the different cities (F = 3.08; df = 1,174;
Q >0.90), types of service organization (F = 3.64; df = 2,174; Q >0.95),
service instructions (F = 6.00; df = 1,174; Q >0.95), and vehicles (F =
14.31; df = 8,174; Q >0.99).
Table 5.10 shows mean idle CO deviation as a function of the city and
type of service organization. San Bernardino service organizations showed
better performance with the mean idle CO deviation for service organization
in this city being smaller than in Riverside. The mean idle CO deviation
was lowest in dealer service organizations, second lowest in independent
garages and highest in service station.
46
-------
Table 5.10
Mean, Post Maintenance Idle CO Deviation in Percent as a
Function of City and Type of Service Organization
Independent
Garages
0.605
0.919
0.762
Dealerships
0.306
0.307
0.306
Service
Stations
0.637
1.683
1.160
Mean
0.516
0.970
0.743
San Bernardino
Riverside
Mean
Table 5.11 shows the mean idle CO deviation as a function of vehicle
and service instructions. The vehicle effect is grouped by the type of
service instruction. It is clear from Table 5.11 that the mean idle CO
deviation differs strongly by vehicle within each group. Table 5.11 also
shows that the lower mean idle CO deviation achieved using emission
inspection instructions is due largely to a negative value obtained for
a single vehicle (1964 Chevrolet) and therefore, suggests that the
significant instruction effect was really a vehicle effect.
The question arises as to what aspect of the vehicles was responsible
for this highly significant effect. The mean idle CO deviation for each
vehicle plotted as a function of the idle CO specification value for that
vehicle is shown in Figure 5.2. The correlation between the idle CO
deviations and the absolute value of idle CO specification is negative
and significant (r = -0.54; df = 232; Q >0.99). This relationship accounts
for 29% of the variance in CO deviations. This correlation suggests that
vehicle with lean idle specifications are not satisfactorily adjusted to
specification with service organizations erroring in a direction to in-
crease CO and HC exhaust emissions. Further, there is a tendency to
over lean older vehicles. It would be significant in the implementation
of an inspection program to determine whether this tendency is an equip-
ment or procedural problem. The relationship between idle CO deviations
and idle CO specification values explains more of the variance in after-
repair measures than any of the other factors the study was designed to
investigate.
47
-------
Table 5.11
Mean Idle CO Deviation in Percent as a
Function of Vehicle and Service Instructions
co
c c
coo
O iH -H
Emiss:
Inspect
Instruct
CO
M C C
o> o o
Paramet
Inspect:
Instruct:!
Vehicle
1964 Chevrolet
1970 Ford
1971 Chevrolet
1970 Plymouth
1971 Volkswagen
Mean
Vehicle
1971 Chrysler
1965 Chevrolet
1971 Ford
1970 Chevrolet
1971 American Motors
Mean
Overall Mean
*
/o
-2.919
2.412
1.307
1.433
-0.102
0.426
0.946
0.553
2.227
1.066
0.507
1.060
0.743
^Deviation in idle fuel to air measured as percent CO. Positive
values indicate fuel to air ratios which are rich relative to
specification.
48
-------
Figure 5.2
MEAN POST-TUNE IDLE CO DEVIATION AS A FUNCTION OF IDLE CO SPECIFICATION VALUE
UJ
z
O
<
2;
Q
O
U
Z
13
CO
O
Q_
I 2
T
3
T
3
c
> 1
0
r
i-i
>
3
c
r
r2
j
-3
-4
70 FORD
O
71 FORD
71 CHEV <
>70 PYMOUT
070 CHEV
C
J71 CHRYSLE
O71 AM
H
I
71 VW
EMI
OPAR/
I
5SION INSTRUCTION VEHICLES
\METERINSTF
O
65 CHEV
AUCTION VEH
ICLES
64 CHEV
2345
CO SPECIFICATION VALUE IN PERCENT
49
-------
5.5.2 RPM
The deviation of the after-repair idle RPM measured from
specification (idle rpm deviation) was used as the dependent variable.
An unweighted means analysis of variance showed a highly significant
effect for vehicles (F = 7.11; df = 8,174; Q >0.99) as well as significant
interactions involving the vehicle and the variable. The service organiza-
tion to vehicle interaction was significant (F = 1.67; df - 16,174; Q >0.90)
and the city to service organization vehicles interaction was significant
(F = 1.64; df = 16,174; Q >0.90). Both these interactions as well as the
vehicle main effect were extracted from the data which was partitioned
by the type of service instruction.
It is clear from Table 5.11 that mean post-tune idle rpm deviation
differed across vehicles within each instruction type. Except for one
vehicle, idle speed was consistently set below specification; a service
error which increases HC emissions.
The mean post-tune idle rpm deviation for each vehicle was plotted
as a function of its idle speed specification, Figure 5.3. With the
notable exception of the VW, there is an inverse relationship between
the post-tune idle rpm deviation and the idle rpm specification value.
Omitting the VW data resulted in a significant, negative correlation (r =
-0.25; df = 214; Q >0.99) between post-tune rpm deviation and its speci-
fication value which accounts for 6.4% of the variance.
5.5.3 Timing
The deviation of the after-repair timing relative to specifica-
tion (post-tune timing deviation) was used as the dependent variable.
Advanced timing carries a positive sign; retarded timing a negative sign.
An unweighted means analysis of variance showed a significant effect for
vehicles only (F = 5.08; df = 8,174; Q >0.99). The vehicle effect is
partitioned by the type of service instruction.
50
-------
Figure 5.3
MEAN POST TUNE IDLE RPM DEVIATION AS A FUNCTION OF IDLE RPM SPECIFICATION VALUE
80
60
40
i
z
20
UJ
zi
^ 0
Z
S
-40
-60
-80
E/
OP>
_»
MISSION INS1
^RAMETER IN!
[RUCTION VEHICLES
ITRUCTION VEHICLES
r-\
65CHEV
64CHEV*
' <
1
71 CHEV
)71AM
) 70CHEV
> 70 FORD
O71 FORD
Q71 0
70 P>
71 VW
HRYSLER
f MOUTH
300
400 500 600 700
RPM SPECIFICATION VALUE IN RPM
800
900
51
-------
It is clear from Table 5.14 that the mean post-tune timing deviation
differed across vehicles. Timing, on the average, was set advanced of
specification within each set partitioned by instruction type, except VW
and American Motors vehicles. This error results in increased HC and NO
emissions, but reduced CO emissions. The mean post-tune timing deviation
for each vehicle was plotted as a function of the pre-tune deviation from
timing specification, as shown in Figure 5.4. An interaction between
service instructions and pre-tune timing deviation is indicated by the
differences in slope between instructional type. The post-tune and pre-tune
deviations were correlated without regard for instructional level. The
correlation obtained (r = 0.33; df = 232; Q >0.98) was significant and
explains 10.9% of the total variation in timing deviations from specifica-
tion.
Table 5.12
Mean Cost in Dollars as a Function of
City and Type of Service Organization
San
Bernardino
Riverside
Mean
Independent
Garages
16.97
25.94
21.45
Dealership
27.21
31.33
29.27
Service
Stations
17.38
20.28
18.83
Mean
20.52
25.85
23.18
52
-------
Figure 5.4
MEAN POST-TUNE TIMING DEVIATION (IN DEGREES) AS A FUNCTION OF PRE-TUNE
TIMING DEVIATION (IN DEGREES)
ex:
o
en
co
Q
Z 6
Z
O EMISSION INSTRUCATION VEHICLES O 5
A PARAMETER INSTRUCTION VEHICLES <
I 4
O
z
5 3
E
Z 2
2 ]
1 71 AM
10 -9 -8 -7 -6 ^ -4 -3 -2 -1
-1
-2
O71VW "3
-4
_
71 FORD A
70 PY MOUTH O
64 CHEV O
70 CHEV A
070 FORD 65 CHEV A
71 CHEV 71 CHRYSLERA
0 1
1 23456789 10
PRE-TUNE TIMING DEVIATION IN DEGREES
-------
Table 5.13
Mean Idle Speed Deviation in RPM as a
Function of Vehicle and Instructions
co
c c
COO
O -H -H
H 4-> 4J
WOO
CO 0) 3
rl P, H
p CO 4-1
W (3 W
M (3
H
CD
c C C
0 0 0
.,- -H -H
l/> 4J 4J
W U 0
^ Q) 3
E P- ^
LJJ CO 4J
C CO
H C
H
Vehicle
1964 Chevrolet
1970 Ford
1971 Chevrolet
1970 Plymouth
1971 Volkswagen
Mean
Vehicle
1971 Chrysler
1965 Chevrolet
1971 Ford
1970 Chevrolet
1971 American Motors
Mean
Overall Mean
Idle RPM *
-13.333
-25.583
-58.250
-53.333
-68.611
-16.378
-50.208
19.792
-45.292
-21.667
-16.042
-22.683
-19.530
*Deviation in idle speed measured as rpm, measured-specification,
negative values are slow speed relative to specification.
54
-------
Table 5.14
Mean Timing Deviation in Degrees as a Function
of Vehicle and Service Instructions
CO
C C
coo
O -H -H
MOO
CO QJ 3
H PH ^1
0 CO J-l
W C co
H C
H
Parameter
Inspection
Instructions
Vehicle
1964 Chevrolet
1970 Ford
1971 Chevrolet
1970 Plymouth
1971 Volkswagen
Mean
Vehicle
1971 Chrysler
1965 Chevrolet
1971 Ford
1970 Chevrolet
1971 American Motors
Mean
Overall Mean
Degrees
2.900
1.650
0.117
3.367
-3.167
0.973
0.708
1.417
4.033
2.375
-0.119
1.683
1.328
*Deviation in basic timing measured in degrees. Positive values are
advanced relative to specification.
55
-------
5.5.4 NOy Control and Spark Plug Misfire
There were significant service organization effects on NO
9
control (X = 10.45; df = 2; Q >0.99) and on spark plug misfire repair
(X2 = 5.54; df = 2; Q >0.90). The rank order of service organization
repair effectiveness for both malfunctions as shown in Table 5.14 was
found to be dealerships, independents and service stations. However,
the level of repair effectiveness on spark plug misfire is uniformly
superior (40 to 100%) to the level of repair effectiveness on NO con-
A
trol (9 to 40%). It is thought that the better relative performance
of dealerships in correcting NO control malfunction results from their
/\
greater experience in handling new cars and their closer association
through bulletins, etc., with the manufacturers.
There were not enough malfunction data for the emission instructions
fleet to test for vehicle effects on NO repair and spark plug misfire
2
repair. However, X tests were performed to determine vehicle effects on
these two repairs in the parameter inspection fleet. There was a signif-
o
icant vehicle effect (X = 10.78; df = 2; Q >0.99) on NOV repair as well
2
as significant vehicle effect (X = 8.90; df = 2; Q >0.98) on spark plug
misfire under parameter instructions. Table 5.15 shows that the NO con-
X
trol on the Chevrolets were more frequently repaired correctly than vehicles
from the other two manufacturers.
Table 5.15
Percent of NOX Control Device Replaced and Percent Misfire (Spark Plug)
Corrected for the Three Types of Service Organizations
Type of Service Organization
Type of
Malfunction Independents Dealerships Service Stations
NO Control 15.1% 39.4% 8.8%
x
Misfire
(Spark plug) 91.7% 100.0% 40.0%
56
-------
Since Chevrolet is the only manufacturer with both 1970 and 1971 NO
X
control devices in California, it is possible that repair agencies are
more likely to inspect this component on Chevrolets because of more
service exposure.
5.5.5 Misfire (Plug wire) and Heat Riser
The only significant effect on plug wire misfire repair
o
performance was type of service instructions (X = 9.17; df = 1; Q >0.99).
The precent plug wire misfire corrected as a function of service organiza-
tions is given in Table 5.16. Plug wire misfire repair when given emis-
sion inspection instructions (93%) was superior to plug wire misfire repair
performance for parameter inspection instructions (60%). Examination of
the two sets of instructional materials indicates that the emission inspec-
tion instructions carried a more specific reference to the probability of
a plug wire misfire malfunction than did the parameter inspection instruc-
tions and therefore performance would be expected to be better. Truth
Chart #4, which accompanied the emission inspection vehicles, included
among "usual causes" of "High HC in all modes" "Secondary wiring defective"
and included among "Authorized Repairs If out of Specification" "Faulty
ignition cable." The parameter inspection instructions listed "Ignition
Misfire" as one of nine items to be checked.
The only significant effect on heat riser repair performance was the
2
service instruction effect (X = 9.78, df = 1; Q >0.99). Repair performance
when given emission inspection instructions, Table 5.17, was superior to
performance given parameter inspection instructions. This could and
probably did result (as will be later discussed) from vehicle effects.
The parameter inspection instructions were the only ones which specifically
mention the heat riser valve. However, the California Highway Patrol
Handbook for Installation and Inspection Stations, does indicate "heat
valve not operating" as one of several causes of high exhaust emissions.
Since the requirement to issue a Certificate of Compliance was implied in
the general instructions for all vehicle repair, the two sets of instruc-
tions may not have had the different impact originally anticipated.
57
-------
Table 5.16
Percent of NOX Control Devices Replaced and Percent of Spark Plug
Misfire Corrected on Vehicles Under Emission Instructions
and on Vehicles Under Parameter Instructions
X
g
Vehicles Under
Emission Instructions
1971 Chevrolet
23.8%
Vehicles Under
Parameter Instructions
1971
Chrysler
7.7%
1970
Chevrolet
40.7%
1971
American Motors
11.5%
60
3 (U
rH M
PLI -H
-------
The single emission inspection instruction vehicle with a malfunctioned
heat riser valve was a 1964 Chevrolet, whereas the two vehicles in the para-
meter inspection fleet having this malfunction were a 1970 and a 1971
Chrysler. Service experience may have biased performance toward the other
vehicle which would have a greater probability of a malfunctioned heat
riser valve than the two newer cars. It is more probable that this is a
vehicle effect rather than a difference in service instruction.
5.5.6 Air Cleaner, PCV Valve and Blade Setting
There were no significant effects for any of the independent
variables (city, type of organization, instructions or vehicles) on the
replacement of adjustment of air cleaners, PCV valves and blade settings.
The percent of malfunctions corrected ranged from 73.9% for air cleaner
to 76.9% for PCV valve. Service organizations are conditioned to replace
these items since parts profit margins are high and labor cost is minimal.
In contrast, their lack of familiarity with choke systems together with
the requirement that the choke blade be inspected before engines have
been warmed up probably explains the extremely poor performance (16.9%)
in adjusting this parameter.
5.5.7 Cost
An unweighted means analysis of variance of repair costs showed
significant effects for the two cities (F = 6.11; df = 1,174; Q >0.95),
service organizations (F = 8.47; df = 2,174; Q >0.95), and vehicle (F =
2.06; df = 8,174; Q >0.95). The service organization to service instruc-
tions interaction (F = 9.21; df = 2,174; Q > 0.99) and the city to service
organization to instructions interaction (F = 6.27; df = 2,174; Q >0.99)
were also significant.
Table 5.18 shows service stations to have the lowest repair cost and
the dealerships to have the highest. The average cost across all service
organizations was higher in Riverside.
59
-------
Table 5.18
Percent Heat Risers Adjusted
as a Function of Instructions
Instructions
Emission Parameter
Heat Riser 66.7% 24.5%
The higher dealership repair costs were first suspected to have
resulted from the procedure used in San Bernardino of sending all vehicle
makes to each manufacturers' dealerships. Lack of familiarity with other
manufacturers' vehicles and unavailability of parts in inventory were
suspected of increasing dealership repair costs. Therefore, in Riverside
the procedure was changed to sending test vehicles to only the appropriate
manufacturers' dealerships. Table 5.18 and the previously discussed
analysis of variance still show a substantially higher average dealership
repair cost in Riverside.
The variability of cost across vehicles partitioned by instruction
type is also seen to be large, Table 5.19. On average, there is no sub-
stantial difference across instruction type. The vehicle effect is not
too surprising since malfunctions were not identical across vehicles. An
approximate indication of the level of vehicle malfunction is also indicated.
Generally, "A" type maintenance consisting of idle parameter adjustments
and component replacements in one of the major subsystems (ignition or
induction) was required on most of the vehicles. The cost of repair is
generally consistent with the degree of malfunction and the type of
engine (4, 6 or 8 cylinder). "A" maintenance ranged in cost between 22 and
29 dollars, idle related maintenance, usually with one additional component
replacement (I), ranged between 17 and 23 dollars. This cost level for
idle adjustments, is higher than the 6 to 8 dollars quoted in a flat rate
repair manual. However, it must be remembered that the repair instructions
60
-------
Table 5.19
Mean Cost in Dollars as a Function of
Vehicle and Service Instructions
CO
c a
COO
0 -H -H
H J-l 4J
WOO
CO QJ d
rl CX V-l
6 CO *J
W C co
M C
II
w
n c c
cu o o
4-1 vl -H
<1) 4J 4J
goo
cd tu d
^l CX, H
td CO 4J
PH C W
M 0
M
Vehicle
1964 Chevrolet
1970 Ford
1971 Chevrolet
1970 Plymouth
1971 Volkswagan
Degree of Malfunction
A
'A
I
I
A
Mean
Vehicle
1971 Chrysler
1965 Chevrolet
1971 Ford
1970 Chevrolet
1971 American Motors
A
A
A
B
I
Mean
Overall Mean
$ 23.33
28.99
17.30
23.48
19.16
22.45
21.71
23.55
29.47
28.31
16.55
23.92
$ 23.18
A = Idle adjustment plus component replacement in either the induction
or ignition subsystems.
B = Idle adjustment plus component replacement in both induction and
ignition subsystems.
I = Idle related adjustments only.
61
-------
were to inspect for all listed malfunctions, thus an additional cost for
diagnosis is incurred even though no failures were present. This state-
ment is also true to a more limited extent with the emission inspection
instruction fleet since a California Certificate of Compliance which
requires the use of an electronic ignition analyzer was also requested
for this fleet.
62
-------
6.0 SUMMARY AND CONCLUSIONS
The data and discussion presented in Section 5.0 suggests the
following conclusions:
t The maintenance effectiveness of all three service organiza-
tion types is marginal at best with regard to most of the
engine parameters investigated.
t The probability of detecting idle CO, idle speed, basic
timing and choke blade kick angle maladjustments is signif-
icantly higher than the effectiveness in setting those para-
meters to within specification tolerances.
e Service organization effectiveness in detecting and repair-
ing failed components which can be corrected by simple
parts replacement is variable. Effectiveness is higher for
those components which are familiar to mechanics (PCV valve,
spark plug, air cleaner elements and ignition wires).
Effectiveness is low for new components such as NO controls.
X
Unnecessary repairs can be expected to occur. The absolute
magnitude of the costs incurred is highly speculative on the
basis of the data available from this program, but can run
from 10 to 30 percent of the repair bill.
Possible causes for the variable maintenance effectiveness have been
speculated upon in Section 5.0. This work has shown that the full benefit
of a mandatory emission inspection and maintenance program cannot be
realized with current service organization practices and procedures.
The data strongly suggest that a large number of repair agencies do not
have systematic, accurate procedures for diagnosing engine tune-up related
malfunctions and maladjustments. Additional investigations should be
conducted to determine the causes of the overall low maintenance effective-
ness prior to implementating mandatory vehicle inspection and maintenance
programs.
Although these conclusions are based upon data acquired in Southern
California, it is unlikely that trends differ markedly on a national basis.
If anything, the quantitative results may be optimistic since: 1) only
California certified class A garages were used which are authorized to
issue Certificates of Compliance for exhaust controls and 2) infrequent
inquiries concerning the test vehicles showed concern that the Highway
Patrol might be auditing performance which have motivated better performance.
63
-------
APPENDIX A
Supplementary Data
1.0 INTRODUCTION
The data shown in Section 5.0 were combined and condensed to
illustrate the major effects observed in analyzing the experimental
data. This Appendix contains expanded tables and charts showing the
data in more detail.
2.0 EXPERIMENT DATA
Tables A-l through A-5 show the experimental data in terms of
numbers of malfunctions submitted and corrected for each parameter
investigated. Tables A-6 through A-16 show the individual vehicle
parameter malfunction and repair data for each parameter tested.
Tables A-17 through A-26 show the compilation of all raw data by vehicle,
Service Organization and instructions.
Table A-27 summarizes the key mode emissions measured for the emis-
sion inspection fleet, vehicles 1 to 5. Since these emissions were
periodically monitored throughout the experiment, ranges of their values
are given. Where malfunctions were changed early in the experiment,
only those emission signatures carried through to program completion are
given.
64
-------
TABLE A-l
ABILITY OF SERVICE ORGANIZATIONS TO DETECT MALFUNCTIONS
TOTAL
MALFUNCTIONS
MALFUNCTIONS
'FOUND
MALFUNCTIONS
NOT FOUND
%
MALFUNCTIONS
FOUND
S,B,
RIV,
S,B,
RIV,
S,B,
RIV,
S,B,
RIV,
INDEPENDENTS
EMISSION
VEHICLES
96
37
52
20
44
17
54%
54%
PARAMETER
VEHICLES
13/1
108
69
58
55
51
52%
9K
DEALERSHIPS
EMISSION
VEHICLES
94
40
57
33
37
7
61?
83%
PARAMETER
VEHICLES
135
104
79
58
56
46
59%
56%
SERVICE STATIONS
EMISSION
VEHICLES
100
40
Gl
24
39
16
61%
60%
PARAMETER
VEHICLES
135
108
60
44
75
64
44%
41%
CM
cn
-------
TABLE A-2
REPAIR ACCURACY (% OF VEHICLES HITHIN LIMITS)
IDLE CO
INDEPENDENTS
DEALERSHIPS
SERVICE STATIONS
cr>
CD
4%-
tt
LU
0_
CO
CD
H
ix-
E
\
EMISSION PARAMETER EMISSION
/EHICLE VEHICLE VEHICLE
PQ >- PQ > PQ >
CO Qi CO Qi CO CcT
90%
68%
47%
26%
88%
75%
38%
13%
95%
80%
70%
40%
94%
«
56%
.
70%
65%
50%
«
QQ<7
OO/i
88%
75%
631
PA
V
RAMETER
EHICLE
PQ >
« i i
CO Qi
95%
75%
70%
40%
87%
67%
67%
60%
Ef
VE
IISSION
:HICLE
PQ >
- k <
m
75%
65%
35%
63%
50%
38%
13%
P
ARAMETER
VEHICLE
PQ >
- » 4
1005
90%
75%
a
81%
63%
44%
31%
-------
TABLE A-3
REPAIR ACCURACY (% OF VEHICLES WITHIN UNITS)
IDLE R.P.M.
INDEPENDENTS
DEALERSHIPS
SERVICE STATIONS
en
EMISSION PARAMETER EMISSION PARAMETER EMISSION PARAMETEF
VEHICLE VEHICLE VEHICLE VEHICLE VEHICLE VEHICLE
CQ > (33 > CQ>p£> CQ>^>
100 RPM -
LU
Q-
co
g 50 RPM -
Q_
Q_
25 RPM -
CO C£
79%
50%
21%
100;
80%
60%
r
CO C£
96%
71%
46%
90%
65%
35%
co ce:
85%
51%
39%
67%
67%
17%
CO C£
92%
68%
56%
90%
53%
12%
co ce:
87%
60%
20%
67%
33%
17%
CO Cd
100J
11%
«
95%
65%
15%
-------
TABLE A-4
REPAIR ACCURACY (% OF VEHICLES HITHIN LIMITS)
BASIC TIMING
.00
INDEPENDENTS DEALERSHIPS SERVICE STATIONS
EMISSION
VEHICLE
f*y^ ^^».
ff\ . CO Qi
± DEGREES FROM SPECIFICATION
^ *?> ^> °<
1 t * i i i
1
75%
71%
63%
63%
63%
42%
42%
77%
77%
56%
44%
44%
33%
22%
PARAMETER
VEHICLE
CO 0£
83%
79%
71%
71%
58%
46%
42%
90%
85%
85%
75%
70%
65%
60%
EMISSION
VEHICLE
_ <
CO C£
m
65%
65%
61%
6B
«HK
«Z
90%
80%
80%
80%
80%
70%
70%
PARAMETER EMISSION
VEHICLE VEHICLE
« - -i
co c*: co cf
92%
88%
84%
80%
76%
60%
48%
90%
80%
68%
68%
68%
68%
58%
76%
68%
64%
56%
56%
28%
28%
80?
707
707
707
70%
60%
60%
P
\
ftRAMETER
VEHICLE
co c2
80%
76%
68%
60%
52%
52%
44%
75%
75%
65%
60%
45%
30%
25%
-------
TABLE A-5
ABILITY TO DETECT AND FIX MALFUNCTIONS
OTHER THAN IDLE CO, ttPM, AND TIMING
MALFUNCTION
NO
X
CONTROL
MISFIRE
(1'LUGWIRE)
MISFIRE
(SPARK PLUG;
AIR
CLEANER
P.C.V.
VALVE
HEAT
RISER
BLADE
SETTING
TOTALS
CITY
S.B.
RIV.
S.B.
RiV.
s.n.
RIV.
s.n.
RIV.
S.B.
RIV.
S.B.
RIV.
S.B.
RIV.
S.B.
RIV.
INDEPENDENTS
EMISSION
NO.
SENT
5
2
9
4
5
1
3.0
4
5
2
5
2
,
-
39
15
NO.
FOUND
0
0
8
4
5
1
6
3
4
2
2
1
25
11
PARAMETER
NO.
SENT
14
12
5
4
10
8
10
8
9
4
9
8
9
8
66
52
NO.
POUND
4
1
1
3
8
8
8
8
6
4
3
1.
0
1
30
26
DEALERSHIPS
EMISSION
NO.
SENT
5
2
10
4
3
2
10
4
5
2
5
2
38
16
NO.
FOUND
2
2
8
4
3
2
7
4
4
2
3
2
27
16
PARAMETER
NO.
SENT
15
11
5
4
10
8
10
8
5
4
10
8
30
8
65
51
NO.
FOUND
6
3
4
4
10
8
7
4
2
3
4
2
2
2
35
26
SERVICE STATIONS
EMISSION
NO.
SENT
5
2
10
4
5
2
10
4
5
2
5
2
40
16
Ntt.
FOUND
1
0
10
4
3
2
8
4
5
2
4
2
31
14
PARAHETEP,
NO.
SENT
15
12
5
4
10
8
10
8
5
4
10
8
10
8
65
52
NO'.
FOUNIl
2
0
2
2
8
7
8
4
5
1
2
1
1
2
28
17
TOTAL
PERCENT
FOUND
21
79
90
73
77
36
15
-------
TABLE A-6
PARAMETER MALFUNCTION DETECTION AND REPAIR
IDLE CO
CAR
NO.
1*
2*
3*
4*
5
6
7*
8*
9*
10*
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
20
21
21
18
26
27
27
27
26
DETECTION
NO.
21
11
18
14
(-)
(-)
25
21
26
23
%
100.0
55.0
85.7
66.7
(-)
(-)
92.6
77.8
96.3
88.5
ADJUSTMENT TO SPEC.
NO,
0
6
11
11
11
15
8
9
15
11
%
0
30.0
52.4
52.4
61.1
57.7
Z9.6
33.3
55.5
42.3
^Parameters were malfunctioned when submitted to service organization.
(-) Parameter was not malfunctioned when submitted to service organization. Service
organization maintenance resulted in some vehicles being ...out of specification
when returned to Scott.
-------
TABLE A-7
PARAMETER MALFUNCTION DETECTION AND REPAIR
IDLE RPM
CAR
NO.
1
2*
3*
4
5
6
7
8
9*
10*
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
20
21
21
18
26
27
27
27
26
DETECTION
NO.
(-)
16
14
(-)
-
-
-
-
25
25
%
(-)
80.0
66.7
C-)
-
-
-
-
92.6
96.2
ADJUSTMENT TO SPEC.
NO.
14
9
14
10
10
9
16
18
20
18
%
66.6
45.0
66.7
47.7
55.6
30.8
59.3
66.7
74.1
69.2
^Parameters vere malfunctioned when submitted to service organization.
(-) Parameter was not malfunctioned when submitted to service organization. Service
organization maintenance resulted in some vehicles being out of specification
when returned to Scott.
-------
TABLE A-8
PARAMETER MALFUNCTION DETECTION AND REPAIR
BASIC TIMING
CAR
NO.
1*
2*
3*
4*
5*
6*
7*
8*
9*
10*
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
20
21
21
18
26
27
27
27
26
DETECTION
NO.
17
-
-
17
10
23
24
19
24
23
%
81.0
-
-
81.0
55.5
88.5
88.9
70.4
88.9
88.5
ADJUSTMENT TO SPEC.
NO.
11
14
21
10
6
14
21
12
18
17
%
52.4
70.0
100.0
47.6
33.3
53.8
77.8
44.4
66.7
65.4
r\>
"Parameters were malfunctioned when submitted to service organization.
-------
TABLE A-9
PARAMETER MALFUNCTION DETECTION AND REPAIR
CHOKE BLADE
CAR
NO.
1
2
3
4
5
6
7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1970
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
(-)
(-)
(-)
(-)
(-)
26
(-)
(-)
27
-
DETECTION
NO.
-
-
-
-
-
7
-
-
10
-
%
-
-
-
-
-
26.9
-
-
37.0
-
ADJUSTMENT TO SPEC.
NO.
-
-
-
-
-
3
-
-
5
-
%
-
-
-
-
-
11.5
-
-
18.5
-
co
(-) Parameter was not malfunctioned when submitted to service organization.
-------
TABLE A-10
PARAMETER MALFUNCTION DETECTION AND REPAIR
AIR CLEANER
CAR
NO.
1
2
3
4
5
6
7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
C-)
(-)
21
(-)
(-)
27
27
(-)
<->
DETECTION
NO.
18
C-)
(-)
14
(-)
(-)
20
19
(-)
(-)
%
85.7
C-)
-
66.7
(-)
C-)
74.1
70.4
(-)
(-)
ADJUSTMENT TO SPEC.
NO.
18
C-)
(-)
14
(-)
<->
20
19
(-)
(-)
%
85.7
C-)
(-)
66.7
(-)
(-)
74.1
70.4
(-)
(-)
(-) Air cleaner was not malfunctioned when submitted to Service Organization.
-------
TABLE A-ll
PARAMETER MALFUNCTION DETECTION AND REPAIR
MISFIRE (SPARK PLUG)
CAR
NO.
1
2
3
4
5
6
*7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
C-)
<_-)
C-)
C-)
18
C_)
4
27
23
c-)
DETECTION
NO.
(-)
C-)
C-)
C-)
16
C-)
2
26
21
(-)
%
-
-
-
-
88.9
-
50.0
96.3
91.3
t-)
ADJUSTMENT TO SPEC.
NO.
-
-
-
-
16
-
2
26
21
(-)
%
-
-
-
-
88.9
-
50.0
96.3
91.3
C -)
en
*San Bernardino Independent Garage Only I
C-) Spark plug not malfunctioned when submitted to Service Organizagion.
-------
TABLE A-12
PARAMETER MALFUNCTION DETECTION AND REPAIR
MISFIRE (PLUG WIRE)
CAR
XO.
1
2
3
4
5
6
*7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
XO.
(-)
20
21
(-)
(-)
C-)
4
C-)
23
(-)
DETECTION
NO.
(-)
17
21
(-)
(-)
(-)
1
(-)
15
(-)
%
(-)
85.0
100.0
( -)
-
-
25.0
-
65.2
-
ADJUSTMENT TO SPEC.
NO.
-
17
21
-
-
-
1
-
15
-
%
-
85.0
100.0
-
-
-
25.0
-
65.2
-
*San Bernardino Independent Garage Only!
(-) Plug wire not malfunctioned when submitted to Service Organization.
-------
TABLE A-13
PARAMETER MALFUNCTION DETECTION AND REPAIR
PCV VALVE
CAR
NO.
1
2
3
4
5
6
7
8
*9
*10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
(-)
( -)
( -)
( -)
( -)
23
c-)
4
4
DETECTION
XO.
19
(- )
(- )
C- )
C- )
(- )
16
C-)
2
3
%
90.5
(-)
( -)
(-)
( -)
( -)
69.6
(-)
50.0
75.0
ADJUSTMENT TO SPEC.
NO.
19
-
-
-
-
-
16
-
1
3
%
90.5
-
-
-
-
-
69.6
-
50.0
75.0
*San Bernardino Independent Garage Only!
(-) PCV valve not malfunctioned when supmitted to Service Organization.
-------
TABLE A-14
PARAMETER MALFUNCTION DETECTION AND REPAIR
HEAT RISER
CAR
NO.
1
2
3
4
5
6
7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
21
(-)
(-)
(-)
(-)
26
(-)
(-)
27
-
DETECTION
NO.
14
-
-
-
-
4
-
-
9
-
%
66.7
-
-
-
-
15.4
-
-
33.3
-
ADJUSTMENT TO SPEC.
NO.
14
-
-
-
-
4
-
9
-
%
66.7
-
-
-
-
15.4
-
33.3
-
00
(-) Heat riser not malfunctioned when submitted to service organizations.
-------
TABLE A-15
PARAMETER MALFUNCTION DETECTION AND REPAIR
NOX CONTROL DEVICE
CAR
NO.
1
2
3
4
5
6
7
8
9
10
MAKE
CHEVROLET
FORD
CHEVROLET
PLYMOUTH
VOLKSWAGEN
CHRYSLER
CHEVROLET
FORD
CHEVROLET
AM. MTRS.
YEAR
1964
1970
1971
1970
1971
1971
1965
1971
1970
1971
TOTAL
NO.
(-)
(-)
21
(-)
(-)
26
(-)
<-)
27
26
DETECTION
NO.
-
-
5
-
-
2
-
-
11
3
%
-
-
23.8
-
-
7.7
-
-
40.7
11.5
ADJUSTMENT TO SPEC.
NO.
-
-
5
-
-
2
-
-
11
3
%
-
-
23.8
-
-
7.7
-
-
40.7
11.5
IO
(-) NO control device not malfunctioned when submitted to Service Organizations.
-------
TABLE A-16
IDLE CO (% v) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1 . CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
4:10
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0.50
0.17
t.OO
4.7S
2.50
/oo1
O.SO
8.4B
3.50
4/| 0
3.70
1.50
0-30
4.7.5
e-30
DEALER
1
2 [ 3
4
s
«J.itf
o./O
4.ZS
cl.50
4,00
o,?0
1/60
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2,50
2./0
4,£>0
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1.50
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4.Sf
4.25
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0.10
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4.00
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0.30
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2.00
1,00
7.60
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MS
t.oo
4.40
5.00
4.5o
S.O3
4.VS
X.lf>
/.oo
3.1o
f.48
7. So
4.40
4. to
4.56
a-*3
4.7S
ff.
-------
TABLE A-17
IDLE RPM (rpm) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1. CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
500
±50
&OO
±50
550
±50
750
±50
850
±50
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
750
±50
450
±50
6i5
±50
too
±50
koo
±50
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2
Soo
575
MO
70O
4RO
475
75O
7,56
900
Boo
500
115
530
65O
4BO
500
750
725
90O
/OSo
3
500
W
MO
575
480
52S
750
775
loo
/«X>
4
5
--JOO
475
480
4?K>
750
57,?
4 SO
625
450
540
Roo
75Q
400
S2§
575
55o
450
fc2$
450
600
DEALER
1
2
3
4
500
490
530
820
4RO
Soo
750
750
100
935
Soo
5oo
R,TO
575
4 BO
525
750
WJ
450
480
4t5
750
feSO
5
SCO
17-1?
530
too
480
SOT)
750
Soo
00
SERVICE STATION
1
2
3
4
5
EMISSION INSPECTION FLEET
SOO
47$
5,-%
SOO
480
Soo
7So
650
°IOO
850
5oo
500
530
&5p
^f?C
5?V>
7SO
S50
"-IOO
/OSO
TOO
fe2fi
530
525
4BO
firto
ISO
70O
0
500
Soo
530
675
4«0
4.V5
?50
fcSo
25
4V^
5/5
450
450
800
650
4oo
550
575
toOo
GOO
5*75
450
600
00
-------
TABLE A-18
BASIC TIMING (degrees) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1 . CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
S. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1*71
9. CHEVROLET
1976
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
4°
± 2."
6."
± a°
3*
+ go
o
±2.°
-5a
±2°
5°
±f
4°
±i'
(e°
±2*
4°
±2°
5°
±Z?
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
14
H
&
8
10
8
10
8
-15
-,5
15
ft
II
/)
it>
8
14
to
o
5
2
14
fc
8
Q
IO
10
IO
/O
-15
-15
3
14
4
8
^
IO
0
10
-2
-15
0
4 | 5
M
4
10
8
IO
0
-Ib
o
n
4
8
M
10
fi
10
o
-15
-15
'5
5
II
4
/&
/t.
14
1(7
P
8
/5
(p
II
4
/fe
13
(4
4
0
5
II
q
/(,
&
14
4
o
Z
15
10
II
'V
14
<=,
o
$
2 | 3
14
(0
f?
10
10
9
/o
-ifc
-15
-'5
(5
5
II
S
it
u
'4
'p
0
?
14
4
B
fc
IO
£
10
o
.
15
3
II
4
\la
Ib
14
8
O
§
4
14
If
'4
(S
O
5
IS
15
H
p
»o
/fc
14
14
o
$
/5
5
H
4i
HP
;t
14
7
0
6>
RIVERSIDE
INDEPENDENT GARAGE
1
14
8
R
e
10
i
10
5
-15
-5
2
14
14
₯3
"4
IO
a
/
14
^
0
<=}
15
5
II
4
\(f
(j>
14
5
o
1
15
5
11
4
(C.
12
14
4
o
1
DEALER
I
H
4
ft
fl
IO
. 8
/o
4,
-IS
-5
2
M
4
R
V
IO
&
IO
o
-IS
-15
IS
o
II
4
ib
i(r
I4
4
o
o
15
5
||
4
\(f
(n
14
4
0
5
3;
_
;
15
5
II
4
\L>
1
14
IO
0
,,'1
4
15
ft
l|
4
ib
12
14
S
-
-
SERVICE STATION
1
2
3
4
14
4
«
(r>
(0
8
10
o
-15
-15
14
4
B
|2
IO
Co
IO
I:O ,
-15
-5
_
.
1
15
7
II
4
it*
(e
14
-q
o
2
IS
I $
II
q
H»
3
(4
n
r>
5
I6)
15
II
l|
Mo
10
'4
M
o
o
If)
O
II
n
HP
4
H
i
o
?
00
ro
-------
TABLE A-19
CHOKE KICK (BLADE) SETTING (In) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1. CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
.010- .105
±.100
,/So
-i-.loo
.ZfcO
ir, 100
.let
±.loo
.084
±.100
:CftO
-E.IOO
.110
±.,IOO
.245
-<-.ioo
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
.loo
.IOO
./5o
.150
zbo
.21,0
.lb°l
.ISO
2
.IOO
.106
I5O
,/SO
.ZbO
.2bO
,11,1
.Itfl
0
o
-
I1f>
.715
.!?n
w
O
0
'9o
.!zo
,/?f>
,I2O
4
<&(>
cfto
,IU>
,240
.Itfl
.Ufi
5
,0=10
.
./20
ttf>
'ftP
I?"
,4Sp
O
o
.aia
,010
no
.110
.110
.015
DEALER
1
(?&>
./So
.ISO
.?f,0
-'to
,ltft
lift
0
0
.cfto
,OfO
.1^0
.ffO
.120
.no
2
.030
.160
.W
.ISO
.?bo
,I(H
Iff
o
0
.ato
.oio
.IfO
110
.l?r>
.110
3
,(flt>
,vt>
,l5o
./so
,zho
i?'5
.let
I7
ffo
./20
.'?0
5
,£>9O
./zo
A?o
./S5
,Ztt>
%&
.!<&
.ttfT
o
o
.010
.120
./fo
,ftQ
l?r>
Q$o
SERVICE STATION
1
2
3
4
5
EMISSION INSPECTION FLEET
,100
.IOO
./.<5p
,/,W
.Z(*>
W5
.C70
.150
.IOO
.IOO
./SO
./So
.?u>
*?4°
f/fff
./tff
.IOO
.lOd
,/So
ISO
?dn
z<#
.ter
,/tf
.100
.IOO
./Si
./<*
?ff\
.Zho
.161
.lift
PARAMETER INSPECTION
O
0
,a=to
WO
./90
,ito
,/?.n
./go
o
.110
.OK>
.090
,/fo
ft0
.Iff
.IZO
o
o
,
O9o
-/»
.110
.i?t>
,IZO
O
o
.cfto
,
.Ift
.IZO
RIVERSIDE
INDEPENDENT GARAGE
1
.090
.100
.ISO
.ISO
.260
260
.IVf
.]&
o
.Zoo
o'io
,/zo
,170
.I1f>
,l?f>
ItS
2
.IOO
.100
./So
-ISO
.Z(,B
.260
./6?
./4f
.iZn
4
o
0
.Cf)0
.Ota
.no
./7y=\
.11,1
2
./(»
.190
>?<*:
r>
o
.060
i?9
Ho
iza
.146
SERVICE STATION
1
/loo
.IOO
.iso
,Z0
./fo
no
i?^
,/?5
2
,IOO
.100
./So
.ISO
.260
26p
fat
.ie\
o
O
.070
.010
.ftp
.f?o
O
o
3
-
O
o
.030
.ofo
'/?r>
./fd
-JZa
17"
4
o
o
.Olo
.^jto
.110
./5t>
.IZf>
.izo
CO
oo
-------
TABLE A-20
AIR CLEANER (degrees or condition) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1. CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2
3
4
5
ISO
ISO
180
180
ISO
CL
180
ISP
180
CL
180
CL
180
CL
ISO
ISO
180
CL
180
CL
ISO
ISO
IfV)
CL
100
CL
ISO
1^0
\8o
CL
186
CL
!l£f>
CL
ieo
CL
ISO
CL
ISO
CL
DEALER
1
2
3
4
5
180
CL
ISO
iff0
|8o
CL
ISO
CL
IRO
CL
ISO
CL
180
CL
ISO
180
ISO
r L-
180
ISO
180
I8o
IffO
CL
ieo
CL
ipo
CL
180
CL
180
CL
160
CL
180
CL
180
IRQ
180
ieo
SERVICE STATION
1
2
an- '< I 5
EMISSION INSPECTION FLEET
180
ISO
ISO
CL
i6o
r.L
180
CL
IB6
IRQ
ISO
CL
ISO
CL
180
CL
180
CL
I6o
CU
PARAMETER INSPECTION FLEET
180
iso
'8p
IB
180
IfiO
lpr>
l#o
ISO
SERVICE STATION
1
2
3
4
IRo
CL
170
C.L
IftTt
CU
180
CL.
-
180
Ifio
Ipo
CL
Ipo
C,L
180
/BO
IflO
I8O
IB&
Ipo
180
CL
Wo
cu
00
-------
TABLE A-21
SPARK PLUG (%misfire) BEFORE AND AFTER MAINTENANCE
NO AND YEAR
1 . CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2 | 3
4
5
k
0
If
O
k
O
t
O
k
O
k
I
4,
0
k
O
k
O
SERVICE STATION
1 | 2 | 3 | 4
5
EMISSION INSPECTION FLEET
&
O
4,
k
k
O
k
k
(t>
O
PARAMETER INSPECTION FLEET
to
O
(,
O
t,
O
k
O
k
O
k
O
(a
0
k
k
k
(f
k
O
RIVERSIDE
INDEPENDENT GARAGE
1
2
3
4
6,
0
k
O
k
O
k
O
4
0
k
O
k
O
k
a
k
O
DEALER
1
2
3
4
G.
O
ta
O
to
0
k
O
k
O
k
O
k
O
L,
0
6.
0
o
k
0
k
o
L,
O
(o
(o
CO
on
-------
TABLE A-22
SPARK PLUG WIRE (%misfire) BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1 . CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
197]
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST -TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST -TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1 | 2
3
4
5
It
0
IZ
o
12
0
12.
o
12.
O
12
o
12
O
12
12
12
-------
TABLE A-23
PCV VALVE CONDITION BEFORE AND AFTER MAINTENANCE
NO AND YEAR
1 CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2
3
4
5
M&
OK
A)&
OK
N&
OK
w&
OK
MG-
«&
WGr
MS-
w&
oK
fOfr
OK
Alfr
N$
WGr
M&
OK
DEALER
1
2
3
4
N|Cr
OK
M&
OK,
/JS-
0K
Mfr
OK
A/S
OK
AJ&
ti(-r
SERVICE STATION
I
2
3
4
N&
OK.
^G-
OK
A^&
AJG-
MS-
MG-
W&
W&
WGr
OK
03
-------
TABLE A-24
HEAT RISER CONDITION BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1. CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
NG-
OK
NG-
Nfr
M&
OK,
2
NG-
w&
fJS-
A/fr
we-
A>&
3
N&
WG
A)G-
/v&
A>&
OK.
4
M&
(OS
fOGr
W6-
5
MG-
OK
NOT-
f'JG-
(06-
Ok
DEALER
1
MG-
W&
WG-
A/fi-
ixlfr
OK
2
NG
0/<
A)G-
WS-
we-
fj&
3
A/e
O«
A/fr
O|^
N&
OK
4
A/(?
M6r
w&
WG-
Mfr
/J&
5
A/6-
OK
/Jfr
f\)&
M&
OK
SERVICE STATION
]
2
3
4
5
EMISSION INSPECTION FLEET
WG-
OK
M&
OK
NG-
A)G-
we
OK
WG-
0«
PARAMETER INSPECTION FLEET
WG-
A/fi-
AJE
/j&
W&-
OK
/OG-
OK
WG-
WG-
W&
W
-------
TABLE A-25
NOX CONTROL DEVICE CONDITION BEFORE AND AFTER MAINTENANCE
CAR MANUFACTURER
NO AND YEAR
1. CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
4. PLYMOUTH
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2
3
4
5
10
10
10
XO
10
10
10
10
10
10
JO
10
10
lo
10
10
10
10
TO
OK
10
10
lo
ro
in
OK
10
10
TO
OK
10
OK
10
ro
ro
ZD
10
ro
DEALER
1
2
3
4
5
TO
OK
TO
TO
10
10
10
10
To
OK
10
ro
LO
OK
10
10
xo
T-0
-LO
OK
10
OK
ro
OK
10
OK
10
OK
ro
ro
TO
10
10
10
10
TO
10
10
10
10
SERVICE STATION
1
2
3
4 | 5
EMISSION INSPECTION FLEET
10
10
TO
oK
TO
10
10
ro
10
10
PARAMETER INSPECTION FLEET
10
TO
To
ro
ro
10
ro
TO
10
oK
10
lo
10
10
TO
10
lo
lo
TO
OK
10
10
10
10
10
ID
10
10
10
10
RIVERSIDE
INDEPENDENT GARAGE
I 1 2
3
4
xo
lo
ro
ro
ro
10
70
OK
10
10
ro
ro
TO
10
10
10
ro
10
TO
10
10
10
10
10
ro
10
r
"1
o
Lo
DEALER
I
2
3
4
r©
OK
10
OK
.
to
10
To
OK
10
10
XO
ro
TO
Ok;
10
lo
lo
10
TO
OK
lo
10
TO
TO
T6
In
.
SERVICE STATION
1
2
3
4
lo
10
10
10
ro
TO
TO
TO
10
ID
10
TO
Tn
TO
10
10
TO
TO
TO
To
TO
TO
lo
TO
TO
To
JO
TO
00
-------
TABLE A-26
REPAIR COST
CAR MANUFACTURER
NO AND YEAR
1 . CHEVROLET
1964
2. FORD
1970
3. CHEVROLET
1971
1970
5. VOLKSWAGEN
1971
6. CHRYSLER
1971
7. CHEVROLET
1965
8. FORD
1971
9. CHEVROLET
1970
10. AMERICAN MOTORS
1971
LOCATION
REPAIR STATION
STATION NO
SPEC
STATE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
PRE-TUNE
POST-TUNE
SAN BERNARDINO
INDEPENDENT GARAGE
1
2
3
4
5
fe/H
34.
|7.^>
7.00
ILSf
I4.-U
iq.^l
7.00
37.CC
yj,cft
fc&3t
33.6.S
30.4)
rt.oo
21.10
n.?7
i.y
Z4.%
Zfe.TI
27-«
^t.ie
43.7?
2i.7l
SERVICE STATION
1
2
3
4
5
EMISSION INSPECTION FLEET
t-31
9.56
7.50
ess
25. ?»
llflO
20.75
H.3S
23.40
B.M
S.«?s
S.«o
IO.-55
/(J.10
66.9)
e.^s
3^5
ZO.OC
29.26
Il.tO
2o.feS
PARAMETER INSPECTION FLEET
12.50
MS
(0.11
fl.1?
4. So
rt.So
22.2fe
52.52
2S«1
il.ol
12.50
2I-4Z
^/.^S
/5.80
/2-So
I2.ec
22. 4S
Z7.0Z
39-07
a- oo
il.40
J7-9?
I3.S\
/<*W!
7.5'M
«S6
II. OO
11.00
IS. 33
i?.V>
'
.
'
10-55
7-fip
H.IS
^.^S
0
7.50
10.%
/0.4(J
LS"
7.50
S.sa
o
v./o
1./0
o
23.7*
l"7./2
34.41
£1.3
IS. pi
-------
Table A-27
KEY MODE EMISSIONS AND ASSOCIATED TRUTH CHARTS
EMISSION INSTRUCTION FLEET WITH MALFUNCTIONS
Vehicle
No.
1 1 3.3-
2. | 0.
45/49 mph
CO HC
4.0 |
tt \
3 | 0.4-2.5 |
4 0.85-1.4
5 | 1.6-2.7 |
1 1 Kev
modes
432-583
618 |
1534-16171
115-184
i 432-48501
failed
30/33 mph
CO HC
| 3.6-4.3
0.6
| 0.4-3.9
1.6-8.9
[ 1.2-1.9
478-524
1 812 |
| 1330-16501
| 130-427 |
I 042-3224|
i
CO
8.6-10.0
3.7
4.0-4.1
13.4-4.3|
1.0-2.7
die*
HC
| 775-1650|
1 1087 1
| 1000-1909J
| 398-455 |
1 690-3970|
Truth Charts
Accompanying Vehicles
1, 5, 7
4, 5
4, 6
2, 5
4, 7
*
Co in % by volume, HC in ppm by volume using Clayton, Key Modes
------- |