United States Office of Air
Environmenta1 Protection and Radiation
Agency Washington. DC 20460
Scr.tamber ,987
Air
EPA Motor Vehicle Tampering
Survey - 1986
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United States Environmental Protection Agency
Office of Air and Radiation
MOTOR VEHICLE TAMPERING SURVEY - 1986
September 1987
FIELD OPERATIONS AND SUPPORT DIVISION
OFFICE OF MOBILE SOURCES
Washington, D.C.
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\
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, B.C. 20460
OCT -5
OFFICE OF
AIR AND RADIATION
1986 Motor Vehicle Tampering Survey Report
Al Mannato, Chief
Regional/State/Local Coordination Section
Regional Librarians
MEMORANDUM
SUBJECT:
FROM:
TO:
Two cfop-i-es—ofTThe Field Operations and Support Division
1986 Tampering Survey are enclosed for inclusion to your
library's periodical section. A limited supply of these
reports are available, so please retain these as permanent
copies and direct any specific inquiries to your Region's Air
Management division, or have them write to:
U.S. EPA
Office of Air And Radiation (EN-397F)
Regional/State/Local Coordination Section
401 M Street S.W.
Washington, D.C. 20460
Verbal inquiries can be directed to Paul Argyropoulos at
202-475-8839 those areas within Regions I, III, V and IX, by
Deanna hughes at 202-475-8837 for those areas within Regions
II, IV, VI, and X, and by Dean Ross at 202-382-2947 for those
areas within Regions VII and VIII.
OCT U 1987
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TABLE OF CONTENTS
EXECUTIVE SUMMARY 1
Introduction 1
Conclusions 3
BACKGROUND 9
SURVEY METHODS 11
Site Descriptions 13
RESULTS 19
Vehicle Tampering 19
Site and Aggregate Totals 19
Tampering Trends 1978-1986 21
Types of Tampering 26
Vehicle Characteristics and Tampering 26
Manufacturer 29
Vehicle Type 29
Vehicle Age 31
Impact of I/M and Antitampering Programs 39
Tampering Trends for Selected Sites 40
Correlation Between Tampering and Idle Emissions 44
Fuel Switching 49
Fuel Switching Indicators and Overlap . . . 49
Fuel Switching Trends 52
Fuel Switching by Vehicle Type 55
Catalyst Tampering and Fuel Switching 55
Gasoline Lead Concentrations 60
APPENDICIES
A. Relevant Portions of Clean Air Act 62
B. Survey and Data Recording Procedures 63
C. Emission Cutpoint for I/M Areas 77
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LIST OF FIGURES
1. Component specific tampering:
1982-1986 surveys 4
2. Overall and catalyst tampering by vehicle model
year - 1986 survey 7
3. Breakdown of surveyed vehicles by condition and
extent of tampering 20
4. Tampering rates by manufacturer: 1986 survey 30
5. Comparison of LOT and LDV tampering in the 1982-1986
surveys 32
6. Cumulative tampering prevalence as a function of
vehicle age for the 1982-1986 surveys 37
7. Cumulative catalyst tampering rates as a function
of vehicle age for the 1982-1986 surveys ... 38
8. Distribution of survey sample among tampering, fuel
switching, and idle test categories ..45
9. Overlap of fuel switching indicators among unleaded
vehicles - 1986 survey 51
10. Overlap of catalyst tampering and fuel switching
among catalyst-equipped vehicles - 1986 survey 57
11. Overlap of indicators used by ATPs to detect missing/
damaged catalysts-1986 survey 59
12. Lead concentrations in leaded fuel sampled from
misfueled vehicles 61
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LIST OF TABLES
1. Tampering Prevalence by Vehicle Type for
Critical Control Components , 7
2. 1986 Tampering Survey Summary 22
3. Trends in Vehicle Condition Classification 23
4. - Comparison of EGR System Tampering to Overall
Tampering in the 1982-1986 Surveys 25
5. Comparison of 1986 Survey Sample to Actual
Nationwide Vehicle Fleet 25
6. Prevalence of Tampering by Component and Survey
Year 27
7. Component-Specific Tampering Rates (percent) by
Survey Location - 1986 Survey 28
8. Tampering Prevalence (and Sample Size) by Model
Year and Vehicle Age at Time of Survey 33
9. Percentage of Catalyst Removal (and Sample Size)
among Catalyst-Equipped Vehicles by Model Year
and Vehicle Age at Time of Survey 34
10. Tampering Prevalence among Vehicles and Components
Covered by Three Antitampering Programs for the
1983-1986 Surveys 42
11. Comparison of Tampering among Missouri Vehicles
(I/M + ATP) and Illinois Vehicles (non-I/M)
Surveyed in St. Louis, MO and East St. Louis, IL
in 1986 42
12. Idle Test Failure Rates (percent) by
Pollutant and Vehicle Condition 47
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13. Mean Idle Emissions by Vehicle Condition 47
14. Fuel Switching Rates among Unleaded Vehicles by
Site and Indicator - 1986 Survey 53
15. Fuel Switching Rates among Unleaded Vehicles by
Indicator and Survey Year 54
16. Combined Tampering and Fuel Switching - 1986 Survey . 56
17. Percentage of Fuel Switching Indicators by Vehicle
Type 57
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EXECUTIVE SUMMARY
INTRODUCTION
Under the direction of the Field Operations and Support
Division (FOSD) of the Environmental Protection Agency (EPA),
contract personnel from Colorado State University (CSU)
conducted a survey of light-duty motor vehicle tampering in
15 cities between April and September, 1986. The areas surveyed
and the total number of vehicles inspected are listed below.
St. Louis, MO 413
East St. Louis, IL 551
Jacksonville, FL 477
Orlando, FL 575
Houston, TX 507
Memphis, TN 580
Pittsburgh, PA 504
Richmond, VA 500
Hartford, CT
Camden, NJ
Covington, KY
Seattle, WA
Los Angeles, CA
Tucson, AZ
Baton Rouge, LA
428
498
500
504
505
499
500
TOTAL
7,541 vehicles
The objectives of this survey were:
1. To make local measurements of the types and extent of
tampering and fuel switching.
2. To extend and update the knowledge gained from earlier
surveys on:
a. The rates of overall and component-specific
tampering and fuel switching.
b. The distribution of tampering by vehicle age,
type, manufacturer, and other variables of
interest.
c. The relationship between tampering and vehicle
idle emissions.
d. The effect of vehicle inspection and maintenance
(I/M) programs and antitamper ing programs (ATPs)
on tampering and fuel switching.
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— 2—
To achieve these objectives, the inspection teams
visually examined emission control devices and measured the
idle hydrocarbon (HC) and carbon monoxide (CO) emissions of
each vehicle. To provide information on fuel switching, the
inspectors sampled gasoline from the tanks of vehicles (for
later laboratory lead analysis), tested for lead deposits in
tailpipes using Plumbtesmo® test paper, and checked the
integrity of the fuel filler inlet restrictors. Four cate-
gories were used to summarize the condition of the inspected
vehicles:
1. Tampered - at least one control device removed or
rendered inoperative
2. Arguably Tampered - possible but not clear-cut
tampering (i.e., may have resulted from either
tampering or malmaintenance)
3. Malfunctioning
4. Okay - all control devices present and apparently
operating properly
These brief but thorough inspections were performed with the
consent of the vehicle owners in a variety of settings more
fully detailed elsewhere in this report.
While the data from a survey such as this seem to invite
inferences regarding program effectiveness, trends, etc., this
approach can easily lead to incorrect conclusions. The sample
size is reasonably adequate for evaluating tampering prevalence
in any particular site, but the sampling of sites is neither
large nor random. Simple comparisons of tampering by site
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across control program categories, for example, can overlook
a variety of confounding factors. These may include geographi-
cal variability, fleet age structure and vehicle mix, variations
in program maturity, coverage, history, and management, and
the interactions among these factors. Straightforward
experimental control of these variables, difficult to achieve
under the best of circumstances, becomes impossible in a
situation where site selection is driven by programmatic
considerations unrelated to the experimental questions.
CONCLUSIONS
In this study the vehicles surveyed were classified as
follows: tampered - 20%; arguably tampered - 25%; malfunc-
tioning - 1%; okay - 54% (overall survey averages). This
gross classification, while useful for some comparisons, is
less informative concerning the emissions impact of tampering
than an examination of component-specific rates. The
percentage of tampered vehicles (20%) is the same as was
found in the 1985 survey.
Component-specific tampering for selected critical
components is shown in Figure 1. The results shown have not
been weighted to compensate for I/M program representation;
these rates probably underestimate the actual nationwide rates.
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Component or SystQm
Catalytic Converter
Evaporative System
Air Pump System
Inlet Restrictor
PCV System
EGR System
////////////////////A 82
Tamponing (%)
1982
1983
1984
1985
1986
J 132
•Change In classification of evaporative system tampering.
hava been 42 using prior classification mathad.
Tampering rate would
Figure 1. ComponQnt-spgcific tamporing:
1982 - 1986 surveys.
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Tampering with evaporative and air pump systems has increased
since 1985, while the rates for other components have remained
unchanged. The increase in evaporative system tampering,
however, is the result of a change in the classification metho-
dology in the 1986 survey, as will be discussed later in the
report. Evaporative system tampering would have been 4% using
the methodology from earlier surveys.
,The catalytic converter removal rate for the 1986 survey
was 5% .overall. Catalytic converter removal increases HC and
CO emissions by an average of 475%, and 425%, respectively.1
For vehicles equipped with three-way converters, substantial
increases in NOX emissions would also be expected to occur.
The air pump system was the most frequently tampered
system (8%) . This is the first survey is which air pump
tampering was the most prevalent form of tampering.
Fuel Switching
Fuel switching, defined as the presence of any of the .
three indicators^, was found in 9% of the unleaded vehicles in
the 1986 survey. , The pattern of overlap among the three misfueling
1 The emissions increases mentioned in this report are from a
study of three-way catalyst vehicles presented in Anti-Tampering
and Anti-Misfueling Programs to Reduce In-Use Emissions from
Motor Vehicles, EPA-AA-TTS-83-10, December 31, 1983.
2 The three fuel switching indicators are: a tampered fuel
filler inlet restrictor, a positive Plumbtesmo® tailpipe test,
or a gasoline lead concentration of more than 0.05 gram per
gallon.
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indicators is discussed in detail later in this report. While
the emissions impact of fuel switching depends upon its duration
and certain vehicle characteristics, emission increases of 475%
for HC and 425% for CO can easily occur.
Age of Vehicle
The probability that a vehicle has been tampered with is
clearly related to its age, as has been shown in previous
surveys. This is evident in Figure 2, which shows the rates
by model year for both overall tampering and catalyst removal.
These age-specific rates are investigated more thoroughly later
in this report•
Vehicle Types
The tampering rates for light-duty trucks were equal to
or higher than for automobiles in every tampering category, as -
shown in Table 1. Overall tampering with trucks was the same
as for automobiles (20%), marking the first time overall truck
tampering has not exceeded overall automobile tampering. This
trend is discussed in greater detail later in this report.
Converter tampering on trucks remained much greater than on
automobiles (9% vs 5%) and fuel switching among trucks was
greater as well (11% vs 8%).
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-7-
Dvorall Tampering
Cotalyvt Toaparlng
--0--
1986 1985 1884 1883 1882 1881 1880 1878 1878 1877 1978 1875
Vahlcla Modal Yaor
Figure 2. Ovarall and catalyst tampering by
vehicle modal year - 1986 survey.
TABLE 1
Tampering Prevalence by Vehicle Type for
Critical Control Components
Tampering Rate (%)
Component /System
Catalytic Converter
Filler Neck Restrictor
Air Pump System
PCV System
Evaporative Control
System
EGR System
OVERALL
Trucks
9
8
10
5
8
7
20
Cars
5
7
8
5
5
7
20
Overall
5
7
8
5
6
7
20
Fuel Switching
11
8
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I/M Programs and Tampering
Tampering in non-I/M sites surveyed was 24%, while
tampering in ATP-only, I/M-only, and I/M + ATP sites were
20%, 18%, and 17%, respectively. Fuel switching was likewise
. greater, in non-I/M areas (12%) than in ATP-only, I/M-only,
and I/M + ATP areas (8%, 8%, 6%, respectively). Such
comparisons across program categories should be made very
carefully, since the number of sites per program category
is small enough that site-specific factors other than program
type may greatly influence tampering prevalence. In addition,
the classification of sites into program categories is
necessarily somewhat rough. The antitampering program in
Baton Rouge, for example, only covers 1980 and newer vehicles.
New Jersey's antitampering program, which was being phased
in over a 16 month period, only covered 1982 and newer vehicles .
at the time of the survey. Because of restricted program
coverage aimed at newer vehicles (those less likely to be
tampered with because of warranty status and age) the impact
of newly implemented programs may not be observable for
several years. The effectiveness of control programs in
deterring tampering among components and model years covered
by each specific program will be investigated later in this
report.
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BACKGROUND
Motor vehicle emissions in urban areas account for nearly
90% of the total carbon monoxide (CO) and airborne lead, over
30% of the hydrocarbons (HC), and nearly 40% of the oxides of
nitrogen (NOX) emitted into the atmosphere. As a result, a major
focus of the nation's efforts to achieve compliance with clean
air standards has been the control of emissions from mobile
sources. The first pollution control devices were installed on
vehicles in 1962, and most light-duty vehicles manufactured
since 1968 have been equipped with a variety of emission control
devices to meet required emissions standards.
The 1977 amendments to the Clean Air Act (sections
203(a)(3)(A) and (B), found in Appendix A) make it illegal for
automobile dealers, repair and service facilities, and fleet
operators to disconnect or render inoperative emission control
devices or elements of design. Regulations issued under section
211(c) of the Act (40 CFR Part 80) prohibit retailers and
wholesale purchaser-consumers from introducing or allowing the
introduction of leaded gasoline into vehicles labeled "unleaded
gasoline only". The EPA's Field Operations and Support Division
(FOSD), formerly the Mobile Source Enforcement Division (MSED),
is responsible for enforcing the tampering and misfueling
provisions of the Act.
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Before 1978, the EPA had data -suggesting that tampering
with emission control devices and misfueling of "unleaded only"
vehicles with leaded gasoline was occurring. Variability in
the inspection procedures, however, prevented an accurate
assessment of the nature and extent of the tampering. As a
result, the Agency began conducting nationwide tampering
surveys of light-duty motor vehicles in 1978 to determine the
rates and types of tampering and fuel switching. These
annual surveys have been conducted either by FOSD directly or
by EPA's National Enforcement Investigations Center (NEIC)
under the direction of FOSD. Consistent inspection procedures
were used throughout these surveys to permit comparisons and
identification of trends.
:The uses for the tampering surveys have evolved since the
first survey was conducted in 1978. Since 1983, the tampering
survey results for some locations have been used to calculate
credits for State Implementation Plans (SIPs), the measures
taken by State and local governments to achieve ambient air
quality standards by reducing mobile source emissions. Data
from the surveys is also used in the default database for the
Agency's mobile source computer model (MOBILES) to estimate
both the emissions loading impact and the reductions that may
be achieved by various control programs. Sites for the surveys
are chosen in light of the need for data on specific areas
either currently operating or considering programs, as well as
the continuing need to monitor the types and extent of tampering
and fuel switching nationwide.
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SURVEY METHODS
The 1986 tampering survey was conducted for FOSD by the
National Center for Vehicle Emissions Control and Safety at
Colorado State University (CSU). Approximately 400 to 600
vehicles were inspected in each of 15 cities between April
and September, 1986, and the entire survey includes 7,541
vehicles. The mix of vehicles inspected was assumed to be a
self-weighting sample, and no attempt was made to approximate
the national vehicle mix.
Each inspection team consisted of at least four members:
three CSU personnel, one or two EPA representatives, and fre-
quently a state or local agency representative. The CSU
personnel, assisted by the state or local person, performed
the actual inspections, while the EPA representative(s)
supervised the survey. Each vehicle inspection included the
following:
1. basic vehicle identification data recorded (year,
make, model)
2. all emission control systems checked
3. idle HC and CO emissions measured
4. fuel sample collected from unleaded-only vehicles for
lead analysi s
5. tailpipe tested for lead deposits using Plumbtesmo®-'-
test paper
6. integrity of fuel inlet restrictor checked
1 Plumbtesmo® is a registered trademark, and appears hereafter
without the ®. It is manufactured by Machery-Nagel, Duren, W.
Germany, and marketed by Gallard-Schlesinger Chemical Corp.,
Carle Place, New York.
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Th e inspection procedures used were consistent with
those of previous surveys, except for one change made in the
classification methodology for evaporative system tampering.
In prior surveys a vehicle with a unsealed air cleaner was
coded as malfunctioning for the evaporative system. In 1986
an unsealed air cleaner was receded as tampering to reflect
the deliberate nature of this condition. As a result,
evaporative system tampering in 1986 was significantly higher
than it would have been if the coding system from earlier
surveys was used. The inspection and recording procedures.
are detailed in Appendix B.
The survey database has been reviewed by CSU and EPA to
ensure its accuracy, and has been offered to the major
automotive manufacturers to review the classification and
reporting of their respective vehicles.
The tampering survey included only 1975 and newer
light-duty cars and trucks fueled with gasoline. For the
purposes of the tampering surveys, a vehicle is considered
to be "unleaded" if a dash label, tank label, or filler inlet
restrictor is observed at the time of the inspection, or if
the emission control label indicates an unleaded fuel
requirement (i.e., catalyst-equipped). A vehicle's designation
as "unleaded" or "leaded" may be changed upon subsequent
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review of the data. Fuel switching rates are thus based
only on the population of unleaded vehicles surveyed.
Similarly, tampering rates for specific components are based
only on the vehicles originally equipped with the component.
The inspections were performed with the consent of the
vehicle owners at either roadside pullovers or inspection
stations. The survey was designed to minimize the refusal
rate of potential survey participants. A high refusal rate
increases the uncertainty in the data gathered, since
individuals who have tampered with or misfueled their vehicles
are less likely to allow their vehicles to be surveyed. The
overall refusal rate was very low (4%), however, and no
survey sites had a refusal rate over 10%. A brief description
of each survey site follows. Unless otherwise noted, the
.survey., sites within a given city were changed daily.
St. Louis, Missouri - I/M + ATP
Dates: April 14 - 18, 1986
Vehicles Surveyed: 413
Fuel Samples: 338
Refusal Rate: 10%
The St. Louis Police Department provided officers to
stop potential survey participants, and the inspectors solicited
permission to conduct the inspections. The decentralized I/M
program includes a catalytic converter inspection on 1981 and
later vehicles, and air pump, PCV, and EGR inspections on all
vehicles.
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East St. Louis, Illinois - non-I/M
Dates:. April 21 - 25, 1986
Vehicles Surveyed: 551
Fuel Samples: . 392
Refusal Rate: ' 5%
Roadside pullovers were conducted with the help of the
Illinois State Police. Inspection locations included East
St. Louis (two days), Washington Park (2 days), and Alorton.
Jacksonville, Florida - non-I/M
Dates: May 5-9, 1986
Vehicles Surveyed: 477
Fuel Samples: 426
Refusal Rate: 3%
Orlando, Florida - non-I/M
Dates: May 12 - 16, 1986
Vehicles Surveyed: 575
Fuel Samples: 475
Refusal Rate: 4%
Roadside pullovers were conducted with the assistance
of the Florida State Police in both Jacksonville and Orlando.
Houston, Texas - ATP-Only
Dates: May 19 - 23, 1986
Vehicles Surveyed: 507
Fuel Samples: 422
Refusal Rate: 7%
The Texas Department of Public Safety provided officers
to assist with the roadside pullovers. Inspection locations
included Houston (three days), La Porte, and South Houston.
The decentralized antitampering program includes Plumbtesmo
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testing and inspection of the catalytic converters and inlet
restrictors on 1980 and newer vehicles, and inspection of the
PCV, air pump, EGR, and evaporative systems on 1968 and later
vehicles.
Memphis, Tennessee - I/M-only
Dates: June 2 - 6, 1986
Vehicles Surveyed: 580
Fuel Samples: 464
Refusal Rate: 1%
The survey was conducted each day at the downtown centralized
inspection station in Memphis. .The inspection team set up
and conducted the survey while vehicles were undergoing the
emissions and safety inspection. The I/M program in Memphis
covers all model years of light duty vehicles.
Pittsburgh, Pennsylvania - I/M-only
Dates: June 16 - 20, 1986
Vehicles. Surveyed: 504
Fuel Samples: 401
Refusal Rate: 4%
The Pittsburgh survey .was ^conducted us.ing roadside
pullovers in the townships.of Penn Hills, Moon, Ross, Shaler,
and Robinson with the help of the local law enforcement
officers in these municipalities. Pittsburgh's decentralized
I/M program covers 1968 and newer vehicles.
Richmond, Virginia - ATP-only
Dates: June 23 - 27, 1986
Vehicles Surveyed: 500
Fuel Samples: 395
Refusal Rate: 4%
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The Richmond survey was conducted using roadside pullovers
with the assistance of the Virginia State Police. Richmond
has an antitampering inspection incorporated into its annual
safety inspection program.
Hartford, Connecticut - I/M-only
Dates: July 7 - 11, 1986
Vehicles Surveyed: 428
Fuel Samples: 341
Refusal Rate: 7%
The Hartford Police Department assisted with the roadside
pullovers. Hartford's centralized I/M program covers 1968
and newer vehicles.
Camden, New Jersey - I/M + ATP
Dates: July 14 - 18, 1986
Vehicles Surveyed: 498
Fuel Samples: 394
Refusal Rate: 8%
The New Jersey Police Department assisted with the
roadside pullovers. New Jersey's I/M program dates back to
1974, and the antitampering inspection is being phased in to
cover 1975 and newer vehicles by May 1987. At the time of
the survey the ATP included a catalytic converter and inlet
restrictor check on 1982 and newer vehicles.
Covington, Kentucky — non-I/M
Dates: July 21 - 25, 1986
Vehicles Surveyed: 500
Fuel Samples: 403
Refusal Rate: 4%
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The Covington survey was conducted in Boone County (two
days), Campbell County, and Kenton County (two days). The
respective County Police Departments assisted with the road-
side pullovers. Covington was a non-I/M area at the time of
the survey, but implemented a decentralized ATP-only in
September 1986.
Seattle, Washington - I/M-only
Dates: August 12 -16, 1986
Vehicles Surveyed: 504
Fuel Samples: 311
Refusal Rate: 3%
The survey was conducted at five centralized I/M stations
in the metropolitan Seattle area. Seattle's I/M program
covers all vehicles in the most recent 13 model years.
Los Angeles, California— I/M + ATP
Dates: August 25 - 29, 1986
Vehicles Surveyed: 505
Fuel Samples: 373
Refusal Rate: 3%
The California Highway Patrol provided officers to assist
with the roadside pullovers. The decentralized I/M + ATP
includes inspection of the catalytic converter, air pump,
PCV, EGR, and evaporative systems on all vehicles.
Tucson, Arizona - I/M-only
Dates: September 8-12, 1986
Vehicles Surveyed: 499
Fuel Samples: 382
Refusal Rate: 1%
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Th e Tucson survey was conducted at three centralized I/M
stations. Tucson was an I/M-only area at the time of the
survey, but added an ATP covering 1975 and newer vehicles in
January 1987.
Baton Rouge, Louisiana - ATP-only
Dates: September 15 - 19, 1986
Vehicles Surveyed: 500
Fuel Samples: 451
Refusal Rate: 4%
The Baton Rouge survey was conducted using roadside
pullovers with the assistance of the Louisiana State Police.
Survey locations were the same as in the 1985 survey. The
decentralized ATP was implemented in September 1985, and
includes a check of the converter, inlet restrictor, and
Plumbtesmo test on 1980 and newer model year vehicles.
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RESLJLTS
A. VEHICLE TAMPERING
1. Site and Aggregate Totals
The vehicles surveyed have been classified into four
categories established by previous surveys: tampered,
arguably tampered, malfunctioning, and okay. Each vehicle
was classified by the worst state of any component in the
vehicle. For example, a vehicle would be classified as
"tampered" if any one component had been tampered, even if
all other components were functioning properly. A vehicle
classified as "okay" must have all observed components
functioning properly!. ^^e criteria used for component
classification are presented in Appendix B. This overall
tampering rate is useful only as a rough indicator of the
emissions impact of a tampering problem, since the different
components making up the rate may have widely varying emissions
implications.
The proportion of inspected vehicles with at least one
tampered component was 20%. Nearly half of the vehicles
surveyed (46%) displayed some form of malfunction, arguable
tampering, or clear tampering of emission control components.
The specific distribution of surveyed vehicles among these
categories is depicted in Figure 3.
1 An "okay" vehicle, however, may still be classified as
fuel switched (see section 3.1., Fuel Switching Indicators
and Overlap of this report).
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Malfunctioning
(1%)
Arguably Tampered
(25%)
Tampered
(20%)
Okay
(54%)
four or more (15%)
three (10%)
-two (21%)
-one (54%)
O
Condition of Surveyed Vehicles Number of Tampered Components
Figure 3. Breakdown of surveyed vehicles by condition and
extent of tampering.
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The frequency distribution of tampering instances for
those vehicles classified as "tampered" is also shown in
Figure 3. Forty-six percent of the tampered vehicles had
multiple components tampered, and 15% had four or more
instances of tampering.
Table 2 summarizes the 1986 survey data by site. As
in previous surveys, the overall tampering in 1986 varies
considerably from site to site. This can be attributed
to the variety of program configurations among the cities
surveyed and to geographic differences.
Table 2 also contains the refusal rate at each survey
site. The overall refusal rate for the survey was very
low (4%), and only one survey site (St. Louis) had a refusal
rate equal to or exceeding 10%. The actual tampering rate
in St. Louis may thus be higher than is reported here,
since individuals who tamper with or misfuel their vehicles
are less likely to allow their vehicles to be surveyed.
2. Tampering Trends 1978-1986
Table 3 shows the overall rates found in each of the
eight tampering surveys. Overall tampering and arguable
tampering generally appear to be decreasing, and the percent
of properly maintained vehicles has been steadily increasing,
The decrease in overall tampering can be examined more
carefully by separating NOx-related tampering (EGR system
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Survey
Location
TABLE 2
1986 Tampering Survey Summary
Number of Tampering Misfueling Survey Refusal
Vehicles Rate (%) Ra^e^J^j Type* Rate (%)
St. Louis, MO
East St. Louis, MO
Jacksonville, FL
Orlando, FL
Houston, TX
Memphis, TN
Pittsburgh, PA
Ri chmond, VA
Hartford, CT
Camden, NJ
Covington, KY
Seattle, WA
Los Angeles, CA
Tucson, AZ
Baton Rouge, LA
413
0 551
477
575
507
580
504
500
428
498
500
504
505
499
500
15
23
21
26
24
21
12
14
13
19
24
18
15
25
23
4
8
9
15
9
14
4
5
5
6
15
4
6
10
10
R
R
R
R
R
C
R
R
R
R
R
C
R
C
R
10
5
3
4
7
1
4
4
7
8
4
3
3
1
4
OVERALL
7,541
20
*R = roadside pullovers, C = centralized I/M stations
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TABLE 3
Trends in Vehicle Condition Classification
Survey
Year
1978
1979
1981*
1982
1983
1984
1985
1986
Tampered
19
18
14
17
25
22
20
20
Arguably
Tamper ed(%)
48
47
45
38
30
29
27
25
Malfunctioning
2
2
3
1
3
4
1
1
Oka;
31
33
38
44
42
46
52
54
*Because the 1981 survey involved only two sites and a very
limited sample size, these results may exhibit more variance
than the other larger surveys.
-------
-24-
tampering) from HC- and CO-related tampering. Table 4
shows that HC- and CO-related tampering have in fact remained
relatively constant since 1983. EGR tampering, however,
has declined markedly since 1983.
Direct comparisons between survey years should be made
carefully, since they do not take into account differences
among"; surveys in site .selection, vehicle age, and car/truck
distributions.' More importantly, because of the 1986
survey's specific goals, it greatly overrepresents the portion
of the national vehicle fleet under local control programs
(see Table 5). Areas with control programs comprised 72% of
the survey sample, while only approximately 41% of the national
vehicle fleet were under such programs.
This discrepancy can be corrected to some degree by
applying a weighting factor to the tampering rates found
under each program type. The 1986 tampering rate weighted '
for program representation is 21%. The 1986 weighted tampering
rate can be compared to the weighted rates from the 1985, 1984,
1983, and 1982 surveys (21%, 26%, 28% and 19%, respectively.)
Applying weighting factors to the 1981 and earlier surveys
would be difficult, since some surveys contained no I/M
areas. The use of weighting factors here also does not account
for differences in program coverage between sites. For the
sake of clarity, only the actual, unweighted rates found
during the surveys will be reported.
-------
-25-
TABLE 4
Comparison of EGR System Tampering to Overall Tampering
in the 1982-1986 Surveys
Tampering (%) by Survey Year
Tampering Category 1982 1983 1984 1985 1986
Overall Tampering 17% 25% 22% 20% 20%
Overall Tampering (excluding
EGR System Tampering) 10* 19* 16* 17 17
EGR System Tampering 10 13 10 7 7
EGR System-only Tampering** 76 4 3 3
* Tampering with idle stop solenoid and vacuum spark retard
were also excluded since these components were not inspected
in 1985 and later surveys.
** Vehicles with EGR system tampering and no other tampering.
TABLE 5
Comparison of 1986 Survey Sample to Actual Nationwide
Vehicle Fleet
Program Percentage within
Type Survey Sample (%)
non-I/M
I/M-only
I/M + ATP
ATP-only
28
33
19
20
Approx . Percentage of
Nationwide Fleet (%)*
59
14
21
6
*Based on 1986 population data gathered from EPA Regional
and State contacts.
-------
- ,'. O -
3. Types of Tampering
The tampering rates \or specific emission control
components and systems for the surveys conducted since 1982
are presented in Table 6. The component-specific tampering
rates for the 1986 survey are presented by survey site in
Table 7. Only those vehicles originally equipped with a
particular component are considered when computing the
tampering rate for that component.
Table 6 shows that tampering with the major emission
control components has generally remained unchanged from the
1985 survey. Air pump system tampering has been gradually
increasing since 1982, and EGR system and catalytic converter
tampering have been decreasing since 1983.
Table 7 shows the wide variation in tampering from site
to site for any given component. Catalytic converter removal,
for example, ranged from 1% in Los Angeles and Hartford to
11% in Covington and Orlando. This range is partly due to
the effectiveness of I/M and antitamper ing programs (as
will be discussed later in this report), geographic location,
and socioeconomic background.
4. Vehicle Characteristics and Tampering
The next section of this report investigates the impact
on tampering of three vehicle characteristics: manufacturer,
vehicle type (car or truck), and age.
-------
-27-
TABLE 6
Prevalence of Tampering by Component and Survey Year
Component/System
Catalytic Converter
Filler Neck
Restrictor
Air Pump System
Air Pump Belt
Air Pump/Valve
Aspirator*
PCV System
Evaporative
Control System
EGR System
EGR Control Valve
EGR Sensor
Heated Air Intake
Vacuum Spark
Retard
Idle Stop
Solenoid
Oxygen Sensor
1982
Survey Year
1983 1984 1985
**
1981
4%
6
5
5
4
1
3
2
10
7
7
1
0
7%
7
7
7
3
1
5
5
13
9
12
1
1
7%
10
7
7
4
1
2
3
10
7
6
1
5
5%
7
7
4
6
2
5
4
7
6
4
1
**
5%
8
7
5
2
5
5***
7
6
5
2
**
**
**
*Vehicles with aspirated air systems are not equipped with
other listed air-injection components, nor do conventional
systems include aspirators.
**Component not checked during survey.
***Change in tampering classification system in 1986.
Evaporative system tampering would have been 4% using the
prior classification method.
-------
TABLE 7
Component-Specific Tampering Rates (Percent) by Survey Location - 1986 Survey
Emission Control Component or System
Survey
Location
St. Louis, MO
East St. Louis, IL
Jacksonvi 1 le , FL
Orlando, FL
Houston, TX
Memphis, TN
Pittsburgh, PA
Richmond, VA
Hartford, CT
Camden, NJ
Covington, KY
Seattle, WA
Los Angeles, CA
Tucson, AZ
Baton Rouge, LA
Catalytic
Converter
2
6
8
11
6
8
3
2
1
4
11
3
1
3
8
Inlet
Restrictor
3
7
7
14
7
12
2
4
3
6
12
4
5
6
9
Air Pump
System
3
10
10
14
8
8
4
7
7
10
11
8
6
10
9
PCV
System
4
5
4
4
7
4
3
4
3
6
3
3
3
11
6
EGR
System
4
9
6
13
9
5
3
5
3
8
10
9
5
9
11
Evaporative
System
4
7
6
7
8
4
3
5
2
4
7
5
5
8
8
Any
Component
15
23
21
26
24
21
12
14
13
19
24
18
15
25
23
I
NJ
00
I
OVERALL
8
20
-------
-29-
Manufacturer. Figure 4 presents the 1986 tampering
rates for each major manufacturer. Separate tampering rates
are listed for each manufacturer with more than 100 vehicles
in the survey. The remaining foreign manufacturers have been
combined into two groups, Other European and Other Asian.
With the exception of Volkswagen, vehicle tampering was
higher among vehicles of domestic manufacture than among
those of foreign manufacture. Overall, tampering with domes-
tically manufactured vehicles was twice that found for the
foreign manufactured vehicles (22% vs. 11%).
A number of factors might explain the discrepancy in
tampering among manufacturers. Differences in design may
make some vehicles more tamper-prone than others. Changing
market share history results in different age distributions
for vehicles of different makes, and vehicle age is clearly
related to tampering prevalence. Tampering rates probably
vary with geographic location and socioeconomic background,
so the owner demographics for different makes may affect the
likelihood of tampering.
Vehicle Type. The overall tampering prevalence for
light-duty trucks (LDTs) was the same as for automobiles
(LDVs), as was mentioned previously (Table 1). While the
tampering rate for each emissions component on trucks was .
equal to or greater than on passenger cars (as in previous
surveys) the 1986 survey is the first in which overall
-------
1
t
-30-
33%
1
1
1
Ford
H Amsricnn Mntors h
-I Gensral Motors
21%
-H Chrysler
20%
Ma?da
13%
I Dther Eurgpean I
10%
I Ut.hBr Asian
Tampering (%)
26%
25%
Figure 4. Tamponing by Manufacturer:
1986 Survey.
-------
-31-
tampering with trucks and cars was the same. Figure 5 shows
that the discrepancy between car and truck tampering has
been decreasing for the past five years.
One factor that may be contributing to the convergence
in car and truck tampering is the increasing sales of imported
trucks. Between 1982 and 1986 the proportion of imported
trucks within the total truck population surveyed has increased
from 10% to 15%. Since imported vehicles are tampered with
much less frequently than domestic vehicles, the increase in
imported trucks within the truck population surveyed may be
contributing to the lower truck tampering prevalence. Another
contributing factor may be the delayed impact of closed loop
technology on truck tampering relative to car tampering.
Closed loop technology first became widespread on trucks in
1983, while it had been widely used on cars since 1981. Any
tampering deterrence from closed loop technology should thus
be evident on cars first, and then later on trucks.
Vehicle Age. Table 8 relates vehicle age and model
year with tampering prevalence for the 1978-1986 surveys.
Catalytic converter removal rates are similarly related to
vehicle age and model year in Table 9. The results from
any given survey are entered diagonally in each table.
The results in Tables 8 and 9 indicate that vehicle
tampering increases directly with vehicle age. Examining
Table 8 diagonally (by survey) shows that tampering increases
-------
-32-
Tampering (%)
35
30
25
20
15
10
0
1982 1983 1984 1985 1986
Survey Year
LDV
LOT
Figure 5. Comparison of LDV and LOT tamponing
in tho 1982 - 1986 surveys.
-------
TABLE 8
Tampering Percentage (and Sample Size) by Model Year and Vehicle Age at Time of Survey
Year of Vehicle Li £e
Madel . ; ;
Year First Second Third Fourth Fifth Sixth Seventh Eighth Ninth Tenth Eleventh Twelfth
1986 1(757)
1985 2(816) 3(1130)
1984 1(462) 2(1001) 5(1018)
1983 7(182)''* 4(471) 6(710) 7(706) i,
u>
1982 1(250) 4(226) 7(466) 9(621) 11(574)
1981 2(57) 7(448) 13(206) 15(458) 11(607) 19(560)
1980 5(63) 9(454) 15(211) 18(516) 25(564) 25(556)
1979 ' 6(371) 9(59) 18(477) 31(288) 28(503) 37(673) 36(699)
1978 7(298) 14(502) 15(79) 21(430) 39(238) 34(559) 37(562) 50(548)
1977 10(457) 15(476) 21(66) 26(316) 44(190) 41(408) 48(452) 48(465)
iy76 18(395) 19(374) 29(52) 26(317) 40(171) 39(385) 49(369) 53(318)
1975 . 22(274) 22(271) 32(22) 37(183) 55(89) , 46(197) 54(194) 60(198)
1974 33(276) 27(242)
1973 32(253) 36(251)
-------
TABLE 9
Percentage of Catalyst Removal (and Sample Size)
among Catalyst-equipped Vehicles by Model Year and Vehicle Age at Time of Survey
Model
Year
1986
1985
1984 .
1983
1982
1981
1980
1979
1978
1977
1976
1975
First
0(757)*
0(808)
0(462)
1(179)
0(250)
0(57)
0(326)
0(291)
Second
1(1128)
0(978)
2(471)
1(225)
2(441)
2(61)
0(445)
1(417)
Third
1(1018)
0(686)
2(465)
5(204)
2(428)
4(55)
1(417)
2(377)
Fourth
1(706)
2(597)
6(457)
3(200)
6(429)
0(71)
2(305)
2(242)
Year of Vehicle Life
Fifth Sixth Seventh Eighth Ninth Tenth Eleventh Twelfth
i
u>
4-
1
1(574)
3(567) 5(552)
6(487) 6(522) 7(528)
12(252) 10(455) 12(572) 12(638)
4(362) 8(213) 8(486) 10(472) 10(466)
2(59) 2(271) 11(166) 14(357) 17(379) 19(409)
10(48) 6(257) 12(139) 12(314) 15(291) 20(276)
2(204) 26(19) 12(139) 23(75) 16(174) 21(1.30) 23(16 /)
*Tampering rates have been rounded to the nearest whole percent. A zero does not necessarily indicate a total
absence of tampering, but rather a level of tampering that rounded to zero.
-------
-35-
coasistently with vehicle age in each survey conducted. In
the 1986 survey, for example/ the tampering rate increases
from 1% for first year (1986) vehicles to 60% among the 1975
model year vehicles surveyed. Table 9 shows a similar,
though less pronounced, increase in catalyst removal. Examin-
ing these tables in this manner has the advantage of comparing
data collected daring one survey in one set of locations, but
Ignores the possible effects of model year differences (i.e.,
technology) on tampering.
Two additional ways of analyzing Tables 8 and 9 address
the impact of model year on tampering rates. Analyzing the
tables horizontally (holding the model year constant) provides
a look at the tampering rates over time for the vehicles of
a particular model year. This approach shows the same distinct
increase in tampering with vehicle age for all model years
since 1975. (The 1974 and 1973 data sets are too small to
permit any conclusions.) For example, the tampering incidence
for 1978 vehicles increased from 7% in their first year to
50% by the ninth year of use. The degree of overall tampering
among very old vehicles (ninth through twelfth years of usage)
appears to remain fairly constant at approximately 50% of the
vehicles surveyed. A similar examination of Table 9 suggests
that converter removal continues to increase among these very
old vehicles. More data from future surveys may be necessary
to discern any trend in tampering among these older vehicles.
-------
-36-
Analyzing Tables 8 and 9 horizontally combines observations
made from different survey sites at different times and
should be undertaken cautiously.
The influence of vehicle age on tampering can be more
clearly seen when the data in Tables 8 and 9 is presented
graphically. Figures 6 and 7 plot overall and catalyst
tampering, respectively, as a function of vehicle age for
the 1982-1986 surveys. This is equivalent to the diagonal
method of analysis used for Tables 8 and 9 that was outlined
previously. Figure 6 demonstrates that the relationship
between tampering rate and vehicle age is not only linear,
but has remained nearly constant over the five most recent
surveys. The strong correlation is obvious despite the
different sizes, vehicle compositions, and locations of'the
surveys. In Figure 7 the catalyst tampering rate remains
negligible for the first two to three years of a vehicle's
life, and then increases thereafter. This delay in catalyst
tampering is understandable, since the emission control
components on all new vehicles are warranted for 5 years/50,000
miles by the manufacturer, providing an incentive to maintain
the catalysts on vehicles still under warranty. A similar
delay in overall tampering would also be expected, but is
not readily apparent in Figure 6.
-------
rin
60
50
40
30
20
10
0
9 (%): S
>- 0
o 4
..&•£•••
f O 0
1" ° A § a
-/ N, Off
a
[ -O ; • i
So
t- * n
* a °
0 °
1 ° A A
O * H u
A. 1®1 , ,- ' , , , ii • ii
urvey Year
1982
*
1983
O
1984
a
1985
A
1986
O
t
>
01 234 56 7 8 9 10 11 12 13
Vehicle Age (years)
Figure 6. Cumulative tampering prevalence as a
function of vehicle age for the
1982 - 1986 surveys.
i
U)
-J
I
-------
Catalyst Tampering (%)
60 n -^ ^—
50
40
30
20
10
:0
b
A
-------
-39-
Tables 8 and 9 can also be analyzed vertically (holding
vehicle age constant), which provides a look at the tampering
rates £or different model year vehicles of the same age.
This approach suggests that improvements in automotive
technology, such as closed loop emission control systems,
may affect overall tampering rates. For example, vehicle
tampering among 1977 model year vehicles surveyed in
their third year of usage was at 18%. By contrast/ only 5%
of the 1984 model year vehicles in their third year of
usage were tampered. A similar vertical analysis of Table
8, however, fails to show a clear pattern or trend in
age-specific catalyst tampering. Vertical analysis of
Tables 8 and 9 introduces the same variability as the
horizontal analysis.
5. Impact of I/M and Antitamperinq Programs
Inspection and maintenance (I/M) programs require vehicles
to meet specific idle emission standards. Vehicles registered
in areas with these programs are required to be periodically
tested to assure that they comply with the specific idle
emission cutpoints established by these jurisdictions. In
addition to reducing emission levels by stimulating better
owner maintenance, I/M programs may deter some tampering with
emission control components. Data from previous surveys has
tended to support this proposition, since tampering in I/M
areas has historically been lower than in non-I/M areas.
-------
-40-
Some I/M areas have also instituted antitampering
programs (ATPs), which involve periodic vehicle inspections
to check the integrity of specific emission control components.
Antitampering programs vary greatly in the components inspected
and the vehicle model years covered, so that a vehicle or
component which would be inspected in one program area might
not be inspected in a different program area. Successful
antitampering programs should reduce existing tampering and
deter future tampering with the components and model years
covered by the program.
The sites surveyed in 1986 can be classified very
generally as four non-I/M areas, five I/M-only areas, three
I/M + ATP areas, and three ATP-only areas. Such classification
is based solely on the presence or absence of a control
program at the time the area was surveyed, and does not take
into consideration variations in program coverage or
effectiveness. Any comparisons between program types (i.e.,
I/M-only vs. non-I/M) should thus be made carefully.
6. Tampering Trends for Selected Sites
The impact of I/M and antitampering programs in specific
locations can be examined by comparing the 1986 survey data
with that from earlier surveys. Comparisons made between
surveys widely spaced in time, however, must take into con-
sideration the differences in average vehicle age in each
-------
-41-
survey. The average miles traveled per vehicle surveyed in
1986, for example, is one third greater than it was in
1983. Since vehicle age is directly related to tampering
prevalence, a significant increase in tampering might be
expected to have occurred between 1983 and 1986, if all
other factors remained constant (car/truck distribution,
owner demographics, etc.). Inferences regarding program
effects should thus be made with this in mind.
Table 10 presents tampering data for three sites -
Camden, Houston, and Baton Rouge. The comparisons made in
this table have been limited to the specific components and
vehicle model years covered by each antitampering program as
of the 1986 survey. The tampering data listed in Table 10
were compiled only for surveyed vehicles included within the
local program jurisdiction. The Houston tampering data,
for example, are for Harris County vehicles only. Any non-
Harris County vehicles surveyed were excluded from this
analysis.
It is difficult to determine from Table 10 whether or
not New Jersey's recently implemented antitampering program
has had any impact on converter and inlet restrictor tampering
found on 1982 and newer vehicles, since the incidence of
tampering on these vehicles was already negligible. As of
May 1, 1987, New Jersey's antitampering program expanded to
1975 and newer vehicles, and future surveys will examine the
program's effectiveness against older vehicles having a higher
tampering prevalence.
-------
-42-
TABLE 10
Tampering Prevalence among Vehicles and Components Covered
by Three Antitampering Programs for the 1983-1986
Tampering Surveys
Tampering Prevalence (%)
Component and by Survey Year
Survey Location Model Years Covered 1983 1984 1985 1986
Camden, NJ Catalytic Converter 82+ - 1% - 0%*
Inlet Restrictor, 82+ - 1 - 0*
Houston, TX Catalytic Converter 80+ 6 - 1* 3*
Inlet Restrictor 80+ 1 - 0* 2*
Positive Plumbtesmo 80+ 7 - 2* 2*
PCV System 75+ 9 - 4* 7*
Evaporative System 75+** 8 - 4* 7*
Air Pump System 75+ 9 - 6* 8*
Baton Rouge, LA Catalytic Converter 80+ - - 4 3*
Inlet Restrictor 80+ - - 31*
PCV System 80+ 2 3*
Evaporative System 80+** 3 3*
EGR System 80+ - - 4 4*
Air Pump System 80+ - 6 4*
* survey was conducted after ATP had been implemented.
^classification of evaporative system tampering changed in 1986 survey.
Evaporative system tampering in Houston and Baton Rouge would have been
5% and 2%, respectively, using the prior coding method.
TABLE 11
Comparison of Tampering among Missouri Vehicles
(I/M + ATP) and Illinois Vehicles (non-I/M) Surveyed
in St. Louis, MO and East St. Louis, IL in 1986
Tampering (%) by State of
Vehicle Registration
Component and
Model Years Covered Missouri Illinois
Catalytic Converter 81+ 0% 2%
Air Pump System 75+ 4 10
EGR System 75+ 4 9
PCV System 75+ 4 6
-------
-43-
The tampering data for vehicles covered by Houston's
ATP-only suggest that this program was less effective in
its second year of operation than in its first. Catalyst
and fuel-related tampering decreased sharply in 1985, after
one year of program operation, and underhood components
covered by the program had moderately reduced rates. Tampering
seemed to have rebounded in 1986, however, particularly for
the underhood components. Baton Rouge's ATP-only has been
partially effective in its first year of operation, since
tampering with 3 of the 6 components covered showed weak
declines between the 1985 survey (before program implemen-
tation) and the 1986 survey (one year after program imple-
mentation). The other three components either did not
change or actually showed higher tampering.
Table 11 examines the difference in tampering found in
St. Louis, MO and East St. Louis, IL. In Table 11 the
vehicles surveyed at these two sites have been classified by
state of registration rather than location surveyed, since a
number of Missouri vehicles were surveyed in Illinois and
vice versa. Also the tampering rates were determined for
the model year and components covered by Missouri's I/M + ATP
to examine the Missouri program's effectiveness. Table 11
shows a dramatic difference in tampering among vehicles in
close geographic proximity but under different control programs.
Part of this difference is probably due to the different
-------
-44-
socioeconomic makeup of the two cities surveyed, but the
presence of an I/M + ATP in Missouri is no doubt a contributing
factor to the lower tampering rates.
7. Correlation between Tampering and Idle Emissions
As was mentioned previously, vehicles which are subject
to an I/M program must meet specific idle emissions cutpoints.
To assess the relationship between tampering and fuel switch-
ing and idle failure rates, the idle emissions from vehicles
have been tested against the cutpoints established by the
I/M program where they were sampled. Vehicles in non-I/M
areas were tested against the cutpoints specified by the tfew
Jersey I/M program. The cutpoints for each I/M area are
listed in Appendix C.
The results of the idle tests are presented in Figure 8
cor vehicles in the various tampering and fuel switching
categories. Only 17% of the surveyed vehicles that were free
of tampering and fuel switching failed an idle test, while
62% of the tampered and fuel switched vehicles failed that
test. These results indicate that a substantially larger
proportion of tampered and fuel switched vehicles than of
okay vehicles fail an idle test at typical I/M cutpoints.
This is partly due to the tendency for tampered vehicles to
have misadjusted carburetors, since 77% of the tampered
vehicles with conventional carburetors also had missing
-------
Figure 8
Distribution of Survey Sample Among Tampering*,
FUQ! Switching, and Idle Test Categories
EntirQ survoy
sample
100%
Okay
54%
Arguably
tamponed
25%
Not fuel
switched
99%
Fuel
switched
1%
Pass
83%
Fail
17%
Tamponed
20%
Ul
I
Not fuel
switched
98%
Pass
73%
Fail
27%
Fuel
switched
2%
Pass
59%
Fail
41%
Pass
38%
Fail
62%
*excludes malfunctioning vehicles (1% of total)
-------
-46-
sealed plugs or limiter caps. It should be noted drovr- Figure
9, however, that 38% of the tampered and fuel switciUid vehicles
were still able to pass the idle test.
Table 12 shows the percentage of vehicles that failed
the idle emissions test for each vehicle condition. The
failure rates are listed for the entire survey, as well as
in two model year groupings representing "old" technology
(1975-1980) and "new" technology (1981+) vehicles. "New"
technology signifies closed loop emissions control, which
came into widespread usage in 1981 model year vehicles.
The overall percentage of tampered vehicles exceeding I/M
cutpoints for HC emissions was nearly three times greater
than for okay vehicles (41% vs 14%). Over five times as
many tampered vehicles exceeded CO cutpoints as did okay
vehicles (44% vs 9%). The majority (60%) of the vehicles
that either had been fuel switched or had their catalysts
removed also exceeded HC or CO limits. Conversely, 40% of
the vehicles with missing catalysts or classified as fuel
switched were still able to pass an idle emissions test. As
in previous surveys, a significant number of arguably tampered
vehicles also produced excess idle emissions. Since the
majority of arguable tampering involves idle speed limiter
caps and sealed plugs, the high failure rate demonstrates
the adverse idle emissions impact of improperly adjusted
carburetors.
-------
-47-
TABLE 12
Idle Test Failure Rates (Percent) by Pollutant
and Vehicle Condition
Failure Rate (%) by Pollutant
for Model Years listed
Vehicle
Condition
Okay
Arguably
Tampered
Tampered
1975-80
HC CO
22
34
44
14
37
49
1981+
HC CO
13
20
29
8
21
27
HC
14
29
41
Overall
CO HC or CO
9
31
44
17
42
57
Cat. Removed
or Misfueled 44 48 38 40 43 47 60
TABLE 13
Mean Idle Emissions by Vehicle Condition
Prgram
Type
non-I/M
I/M*
ATP-only
HC emi ssions(ppm)
Tampered Okay
402.6 51.4
280.2
328.9
51.5
45.2
CO emissions(%)
Tampered Okay
3.5 0.4
2.4
2.8
0.3
0.4
OVERALL 346.1 50.6 2.9 0.3
* category includes any program where idle emissions are
checked, including I/M + ATP areas.
-------
-48-
The effectiveness of idle emissions testing on "new"
technology vehicles can also be seen in Table 12. The data in
Table 12 actually minimizes the impact of "new" technology
because "old" technology trucks manufactured after 1980 have
been included in the "new" technology category due to the
model year split. As was found in the 1985 survey, idle emissions
testing is more effective in identifying tampering on 1980
and older vehicles than on 1981 and newer vehicles. For example,
49% of the tampered "old" technology vehicles exceeded CO
cutpoints compared to 27% of the tampered "new" technology
vehicles. This suggests that idle emissions testing may not
be an effective strategy for identifying tampering and fuel
switching among "new" technology vehicles, since many vehicles
with closed loop systems are able to produce low idle emissions
even with tampered emission control devices.
The mean idle emissions for tampered and okay vehicles are
presented in Table 13 by program type. Vehicles from Baton
Rouge are considered to be ATP-only for model years 1980 and
newer, while vehicles from model years 1975-1979 are classified
as non-l/M (following the program coverage in the area). The
vehicles surveyed in Memphis are classified as I/M for CO
emissions but as non-I/M for HC emissions because the I/M
program effectively has no cutpoints for HC (see Appendix C).
Also areas with I/M or I/M + ATP have been combined in Table 13.
-------
-49-
The mean idle emissions from tampered vehicles were
considerably greater than from properly maintained vehicles
(Table 13). Overall, HC emissions from tampered vehicles were
nearly seven times greater on average than from okay vehicles,
while CO emissions were nearly 10 times greater. Tampered
vehicles from areas with I/M programs had the lowest average
HC and CO emissions, while tampered vehicles from areas with
ATP-only had slightly higher average emissions. The slightly
higher idle emissions from vehicles in ATP-only areas is not
surprising, since these vehicles have not been tuned to pass
I/M cutpoints.
B. FUEL SWITCHING
1. Fuel Switching Indicators and Overlap
Fuel switching is more easily defined than measured,
since no single indicator can accurately determine its preva-
lence. Since 1981 the surveys have used a combination of
three indicators to measure fuel switching more accurately:
a tampered fuel filler inlet restrictor, a positive Plumbtesmo
test for lead deposits in the tailpipe, and a gasoline lead
concentration of more than 0.05 grain per gallon (gpg) • Of
these three indicators, only a tampered inlet restrictor is
also considered tampering, and as such is used to calculate
both tampering and fuel switching rates. Since false positive
indications should be extremely rare for these measures, the
percentage of vehicles with at least one positive indicator
is a reasonable minimum estimate of fuel switching.
-------
-50-
The presence of any of these three indicators suggests
that a given vehicle has been misfueled; their absence, how-
ever, does not rule it out. For example, fuel samples could
only be obtained from 81% of the .unleaded vehicles surveyed,
limiting the scope of this variable. A vehicle misfueled .
repeatedly with leaded gasoline may also have little detect-
able lead in its fuel tank due to subsequent proper fueling.
Similarly, a vehicle with an untampered fuel filler inlet
restrictor may have been fueled at a leaded pump equipped
with a smaller nozzle, or by using a funnel or similar device,
The tailpipe lead test, due to the difficulties of field
administration, may also fail to identify misfueling, and
older vehicles may have had their tailpipes replaced since
last operated on leaded fuel. As the lead phasedown program
is lowering lead levels in leaded gasoline, the incidence of
false negative Plumbtesmo results may be increasing. The
uncertainty in these measures, then, is always toward under-
estimating the number of vehicles misfueled. .- .,
The limitations of the fuel switching indicators can be
seen in their incomplete overlap. The results from these
indicators would be expected to overlap significantly, since
they are three indicators of the same phenomenon. This has
not held true, however, in the 1986 survey or in previous
surveys. The Venn diagram (Figure 9) illustrates the degree
of overlap in the misfueling indicators for all unleaded
-------
.-51-
Positiva Pluvfatoano
(278 Total)
Landed Fual in Tank
(255 Total)
Tanperad Inlat
Rastrlctnr
(441 Total)
Tampered Inlat Only,
(37X)
PlumbtosBO » Gas
<3X)
Plunfatacnio » Inlat
(HZ)
Cos » Inlat
(2X)
Loaded COB Only
(11X)
PluntatacBO Only
(6X)
Thraa Indicatare
(30X)
Figure 9. Overlap of fuel switching indicators among
unleaded vehicles - 1986 survey.
-------
-52-
vehicles surveyed in 1986 in which data for all three indicators
were recorded. For example, only 72% of the vehicles having
leaded fuel in their tank also registered a positive Plumbtesmo
test. Additionally, only 41% of the vehicles with tampered
inlet restrictors actually had leaded gasoline in their
tanks at the time of the survey. The incomplete overlap
reflects the limitations of each indicator as well as the
different aspects of fuel switching each indicator identifies.
Figure 9 also shows that 80% of the fuel switched vehicles
had a tampered inlet restrictor, making it the most frequently
observed indicator of fuel switching. A positive Plumbtesmo
result was observed on 50% of the fuel switched vehicles,
while leaded fuel was found in the tanks of 46% of the fuel
switched vehicles sampled. An antitampering program consisting
of an inlet restrictor inspection and a Plumbtesmo test
would have detected fuel switching in 89% of the fuel switched
vehicles surveyed in 1986.
2. Fuel Switching Trends
Of the vehicles requiring unleaded fuel, 9% were
identified as misfueled by at least one of the indicators
discussed above. The fuel switching incidence by survey site
is listed in Table 14. Table 15 compares the prevalence of
each fuel switching indicator in the 1986 survey with previous
surveys. The data in Table 15 suggest a general pattern of
-------
Survey
Locati?'
East St. Louis, 1L
Jacksonville, FL
Orlando, FL
Covington, KY
Memphis, TN
Pittsburgh, PA
Hartford, CT
Seattle, WA
Tucson. AZ
St. Louis, MO
Camden, NJ
Los Angeles, CA
Houston, TX
Richmond, VA
Baton Rouge, LA
-53-
TABLE 14
Switching Rates Among Unleaded Vehicles By
Site and Indicator - 1986 Survey
Leaded
Fuel in
Tank (%)
5
5
8
9
7
3
3
2 " .
3
2
2
1
6
2
6
Tampered
Inlet
Restrictor (%)
Non-I/M Areas
7
7
14
12
I /M- only Areas
12
2
4
4
6
I/M + ATP Areas
3
6
5
ATP-Only Areas
7
4
9
Positive
Plumb tesmo
(%)
4
5
8
10
7
2
1
2
6
1
2
1
5
3
7
Overall Fuel
Switching (%)
8
9
15
15
14
4
5
4
10
4
6
6
9
5
10
AIL SITES
-------
-54-
TABLE 15
Fuel Switching >Rates Among Unleaded Vehicles
by Indicator and Survey Year
Survey Leaded Fuel Tampered Inlet Positive Overall Fuel
Year in Tank(%) Restrictor(%) Plumbtesmo(%) Switching (%)
4
10
16
11
14
14
9
9
*?lumbtesmo test not used.
1978
1979
1931
1982
1983
1984
1985
1986
4
10
7
6
7
8
5
5
3
4
6
6
7
10
7
7
*
*
8
7
10
9
5
4
-------
-55-
decline in fuel switching. Since such a pattern could result
from the selection of sites surveyed this year, strong con-
clusions must await the data from subsequent surveys.
Table 16 presents the combined tampering and fuel switching
rates for the 1986 survey. The percentage of unleaded vehicles
that were tampered or fuel switched was 20%, and the percentage
of unleaded vehicles with missing or damaged converters was 10%.
Table 16 thus suggests that half of all tampering and fuel
switching is composed of vehicles in the catalyst removed or
fuel switched category. Since these conditions have the
largest emissions impact, this indicates the very serious
nature of most tampering.
3. Fuel Switching by Vehicle Type
The prevalence of each fuel switching indicator by
vehicle type is presented in Table 17. Overall fuel switching
among t-rucks was higher than for passenger cars (11% vs. 8%)
and the prevalence of each indicator was also greater among
trucks.
4. Fuel Switching and Catalyst Tampering
Consumers and mechanics remove catalytic converters for
a number of reasons, but much of their motivation is related
to fuel switching. The vehicle owner may remove the catalytic
converter either prior to misfueling, or after some misfueling
-------
-56-
TABLE 16
Combined Tampering and Fuel Switching - 1986 Survey
Catalyst-equipped vehicles
Unleaded Vehicles
Survey
Location
East St. Louis, IL
Jacksonville, FL
Orlando, FL
Covington, KY
with catalysts removed or
that were fuel switched (%)
Non-I/M Areas
10
12
19
18
either tampered o
fuel switched (%)
23
22
27
25
Memphis, TN
Pittsburgh, PA
Hartford, CT
Seattle, WA
Tucson, AZ
St. Louis, MO
Camdem, NJ
Los Angeles, CA
Houston, TX
Richmond, VA
Baton Rouge, LA
I/M-only Areas
16
6
6
6
11
I/M + ATP Areas
5
9
7
11
6
13
ATP-only Areas
22
13
14
16
26
16
19
16
25
15
25
TOTAL
10%
21%
-------
-57-
Table 17
Prevalence of Fuel Switching Indicators by Vehicle Type
Fuel Switching Indicator
Tampered Inlet Restrictor
Positive Plumbtesmo
Leaded Fuel in Tank
Overall Fuel Switching
Percent Fuel Switching by Vehicle Type
LDV LOT
7
4
4
8
8
8
7
11
Catalyst Tampering
(336 Total)
Fu«l Switching
(543 Total)
Figure 10. Overlap of catalyst tampering and fuel switching
among catalyst-equipped vehicles - 1986 survey.
-------
-58-
if the vehicle's driveability has been adversely affected by a
catalyst damaged from the repeated misfueling. The data from
this survey cannot be used to distinguish between these two
situations, but can be used to examine the extent to which
these types of abuse occur in conjunction.
Figure 10 depicts the degree of overlap between catalyst
removal and fuel switching. Vehicles with catalyst tampering
exclusive of fuel switching were relatively uncommon — only
38% of the catalyst tampered vehicles were not fuel switched.
Fuel switching, however, is not always accompanied by catalyst
removal, since 62% of the fuel switched vehicles still had
their catalysts.
Figure 11 examines the relationship between converter
tampering and two of the three misfueling indicators (positive
Plumbtesuio and tampered inlet restrictor) . Only vehicles in
which all three of these parameters were inspected are included
in Figure 11. These three criteria have been incorporated
into a number of antitampering programs, such as in Houston
and Baton Rouge, to determine if a converter is missing or
damaged. A vehicle failing the Plumbtesmo test or inlet
restrictor inspection in these programs would have to have
its converter replaced.
-------
-59-
Poeitive Pluwbtaemo
(303 total)
Missing Catalytic
Cnnvartar
(367 Total)
Tampered Inlat
Restrictor
(471 total)
Tampered Inlat Only
(262)
Plumfataona * Cat.
(22)
Cat. » Inlat
(90
Converter Only
(202)
lunfatocae Only
(72)
All
Three Indicators
(242)
Inlat » Pluafatacmo
(122)
Figure 11. Overlap of indicators used by ATPs to detect
missing/damaged catalysts - 1986 survey.
-------
-60-
Figure 11 shows the value of these programmatic criteria
in detecting missing or damaged converters. A simple inspection
of the converter for example, would only catch 55% of the
vehicles with missing or damaged converters. Inspecting
both the converter and inlet restrictor, however, would
detect 93% of these vehicles. The usefulness of Plumbtesmo
as an indicator may be declining with the advent of lead
phasedown, since only 7% of the vehicles in Figure 11 failed
for Plumbtesmo only. In 1984, prior to lead phasedown, 17%
of the vehicles failing one of these programmatic criteria
failed for Plumbtesmo only.
5. Gasoline Lead Concentrations
Of the vehicles identified as misfueled by any of the
three misfueling indicators, 52% had only trace amounts of
lead (less than 0.05 gpg) in their gasoline when inspected.
These vehicles, then, were identified as fuel switched by a
tampered filler restrictor and/or a positive Plumbtesmo
test. Figure 12 presents the distribution of lead concen-
trations of 0.05 gpg or more in misfueled vehicles. The
impact of lead phasedown can be dramatically seen when
Figure 12 is compared to similar data from the 1984 and 1985
surveys. In the 1984 survey 39% of the misfueled vehicles
had a gasoline lead concentration in excess of 1.0 gpg/
compared to 1% in 1985 and 1986. The distribution of lead
concentrations in 1986 is centered on the 0.2-0.4 gpg range,
compared to 0.4-0.6 gpg in 1985 and 1.0+ gpg in 1984.
-------
-61-
Percentage of Mlcfueiad Vahlclas
15
10
10Z 10Z
92
7X
VTA VTA
JZ
Y7A
Gasoline Lead Concentration (grams/gallon)
Figure 12. Lead concentrations in leaded fuel
sampled from misfueled vehicles.
-------
-62-
APP6NDIX A
RELEVANT PORTIONS OF THE CLEAN AIR ACT
Section 203{a)(3): The following acts and the causing thereof
are prohibited —
(A) for any person to remove or render inoperative any device
or element of design installed on or in a motor vehicle or
motor vehicle engine in compliance with regulations under this
title prior to its sale and delivery to the ultimate purchaser,
or for any manufacturer or dealer knowingly to remove or
render inoperative any such device or element of design after
such sale and delivery to the ultimate purchaser; or
& .
(B) for any person engaged in the business of repairing,
servicing, selling, leasing, or trading motor vehicles or
motor vehicle engines, or who operates a fleet of motor
•~N
vehicles, knowingly to remove or render inoperative any
device or element of design installed on or in a motor
vehicle or motor vehicle engine in compliance with regulations
under this title following its sale and delivery to the
ultimate purchaser.
-------
-63-
APPENDIX B
SURVEY AND DATA RECORDING PROCEDURES
1. Explanation of Survey Forms
The forms on the following pages were used for recording
the survey data in the field. The forms were forced choice to
ensure coding consistency, and were designed to facilitate
direct data entry. The following codes were used to record
data for the major system components on the data sheets:
0 - Not originally equipped 8 - Misadjusted item
1 - Functioning properly 9 - Malfunctioning
2 - Electrical disconnect A - Stock equipment
3 - Vacuum disconnect B - Non-stock
4 - Mechanical disconnect D - Add on equipment
5 - Incorrectly routed hose Y - Yes
6 - Disconnect/Modification Z - No
7 - Missing item
Additional codes were used for those components which
could not be classified into the above categories. If a
determination could not be made about a given component's
condition, the variable was left blank. A brief description
of each data entry follows.
-------
1986 TAMPERING SURVEY - PART A (UNDERHOOD)
30
13
N 0
4
Y R
(
*
i
12
MOI
10 NUMBER
I/M 3TICKER(datas
of last Inspection)
DISPLACEMENT (cubic
Inches or liters)
40
HEATED AIR INTAKE 43
ft- Mot orig. equipped
1- Funct. properly
3- Vacuum disconnect
IT* Mech. disconnect
7- Missing item
(stovepipe hose)
9- Kalfunct. item
(vac. override)
B* Hon-stock(custom A A
air cleaner)
PCV SYSTEM
]_-Funct. properly
ASPIRATED AIR
INJECTION SYSTEM
ft- Mot orlg. equipped
(If conventional
system or none)
1- Funct. properly
l\- M«ch. disconnect
7- Missing Item
9- Malfunctioning
AIR PUMP BELT
(if Aspir., code "0")
ft- Mot orlg. equip.
48 CARBURATOR TYPE
$- Sealed
F- Fuel Injection
A- Stock
- Mon-stock
D
49
**NOTE: If engine fan. Is missing
or Illegible, copy sll but the
last 6 digits of the VIM. DO
NOT COPY SERIAL NUMBER PORTION
Of VIH.
15 ENGINE FAMILY
41
26 VIN
(If engine family not available)
36
37 ORIGINALLY CATALYST EQUIPPED?
FROM STICKER UNDER HOOD OR
DRIVER'S DOOR POST 42
Y-Tes
2- No
X- Can't tell (no sticker,
not readable, or not mentioned)
38 AIR CLEANER
A- Stock
B- Non-Stock
7- Missing Item
3-Vacuum disconnect
{{-Mech. disconnect
(fresh air hose)
/-Missing Item
9-Malfunct. Item
(collapsed hose)
g-Non-stock (Inc. fuel
economy devices)
TURBOCHARGER
0- Mot orlg. equipped
A- Stock
B- Non-stock
D- Add-on
50
1- Funct. properly
7- Missing Item
&- Mlsadjustcd Item
(loose)
45 AIR PUMP SYSTEM (Incl. valve)
0- Mot orlg. equipped (If
aspirated or none)
1- Funct. properly
51
EVAP. CONTROL
SYSTEM
1-Funct. properly
48
D
5-Vacuum discon.
(carb. line) • ^f
/{-Mech. discon.
(tank line)
5-Incorr. routed hose
5-Dlsconnect/Modiflcatlon
(air cleaner unsealed)
7-Mlssing Item
9-Malfunct. Item
(or cannlster cracked)
4- Mech. disc, (other
than belt removal)
7- Missing Item
9- Malfunctioning
(frozen)
EXHAUST MANIFOLD
A- Stock
B- Mon-stock
OXYGEN SENSOR
DO- Not orlg. equipped 52
1- Functioning properly
2- Electrical disconnect
1|- Mech. disc, (unscrewed)
7- Missing itea
00 DOT MM WI1MOUT M»»lttlO» 0' *
LIMITER CAPS
~~"~1 0- Mot orlg. equipped
(fuel injection)
].- Funct. properly
t|- Mech. disconnect
(tabs broken or bent)
7- Missing item
8- Misadjusted (sealed
plugs removed)
EGR CONTROL VALVE
Q-Not orlg. equipped
1-Funct. properly
3-Vacuun disconnect
l|-Mech. disconnect
/-Missing Item
9-Malfunct. Item(explain)
D
EGR SENSOR
(coolant, back-pressure, etc.)
ft- Not orlg. equipped
1- Funct. properly
3~ Vacuum disconnect
£. Xncorr. routed hose
7- Missing itea
COMPUTER SYSTEM
A RELATED SENSORS
ft- Hot orig. equipped
1- Funct. properly
5- OUconnecJ/Modllloallos
«' •«"*""•
(explain)
r •
-------
1986 TAMPERING SURVEY - PART B (REAR)
J ID NUMBER
MAKE
(write out)
MODEL
(write out)
12
13 VEHICLE TYPE
C- Car
J- Truck (includes vans)
14
LICENSE PLATE
(Scace)
25
26 DASH LABEL
0- Not orig. equipped
1- Funct. properly
(present)
7- Missing item
31 TANK LABEL
0- Mot orig. equipped
1- Funcc. properly
(present)
7- Missing Item
CATALYTIC CONVERTER
0- Not orig. equipped
3.- Funct. properly
(present)
7- Missing item
28 EXHAUST SYSTEM
/\- Stock
U- Non-Stock
16
20
23
i
i
22
19
IDLE HC
(PPM)
IDLE CO
tt)
ODOMETER
(Thou.)
dv
30
29 EXHAUST SYSTEM
INTEGRITY
1- Funct. properly
(no obvious leaks)
9- Malfunctioning
(leaks evident)
30 TANK CAP
1- Funct. properly
7- Missing item
9- Malfunctioning
(loose,or unsealed)
FILLER NECK
32 RESTRICTOR
0- Not orig. equipped
1- Funct. properly
l\- Mech. disc, (widened)
7- Missing Item
33 PLUMBTESMO
P- Positive
H- Negative
34 FUEL SAMPLE
Y- Yes
Z- No
leave blank
35
i
CTi
Ul
I
FUEL DATA
38
DO NOT U>« WITHOUT PlftUUIION Of THI OtHCl Of HflltMCM. 0«VIIOMUJNT i THAUHDO
-------
-66-
Fbrro A -. Underhood
1-4 ID Number - Vehicles are numbered sequentially as
they are inspected. This number is preceded by a
site identifying letter.
5-8 Month and year of last I/M inspection (left blank
if vehicle is licensed in non-I/M area).
9-12 Displacement - as recorded on the underhood emission
label.
13r-l4 Vehicle Model year
15^-25 Engine Family - as recorded on the underhood emission
label.
26-36 Non-serial number portion of VIN - as recorded on the
driver's side of the dash under the windshield or the
driver's door post. The VIN is recorded only if the
engine family can not be determined.
37 Originally Catalyst Equipped - as recorded on the
underhood emission label or the driver's door post.
38 Air Cleaner - is coded 'A', 'B1, or '7'.
-------
-67-
39 Heated Air Intake - provides warm air to the carburetor
during cold engine operation. The heated air intake
is coded '0', '!', '3', '4', '7' (stovepipe hose),
'9' (vacuum override), or 'B1 (custom air cleaner).
40 Positive Crankcase Ventilation (PCV) system - prevents
crankcase emissions by purging the crarikcase of blow-
by gases which leak between the piston rings and the
cylinder wall in the combustion chamber under high
pressures. The PCV system is coded '!', '3', '4'
(fresh air hose), '7', '9', or 'B1 (includes fuel
economy devices).
41 Turbocharger - coded 'O1, 'A', 'B1, or 'D'.
42 Evaporative Control System (ECS) - controls vapors
from the fuel tank and carburetor. Some systems have
two lines: from the fuel tank to the canister, and
from the canister to the carburetor or air cleaner
(for purging the canister). Other systems have a
third line connected to the carburetor. The ECS is
coded '!', '3' (carburetor line), '4' (tank line),
'5', '6' (air cleaner unsealed), '7', or '9' (cracked
hose or canister).
Air Injection System - extends the combustion process
into the engine's exhaust system by injecting fresh
air into the exhaust ports, lowering exhaust emissions
while still maintaining proper vehicle performance.
-------
-68-
Two types of air injection systems are currently used.
One type uses a belt-driven air pump to direct air
through a control valve and into the exhaust manifold.
The other type is a Pulse Air Injection Reaction
(PAIR) system, which uses an aspirator commonly
located in the air cleaner to supply air to the exhaust
manifold.
43 PAIR - coded '0' (if air pump system or none), '!',
'4' , '7', or '9' .
44 Air Pump Belt - is coded '0' (if PAIR or none), '!',
'7', or '8' (loose belt).
45 Air Pump System - for the purposes of this variable,
consists of the air pump and control valve and is
coded '0' (if a PAIR or none), '!', '4' (other than
belt removal), '7', or '9'(frozen pump).
46 Exhaust Manifold - coded 'A' or 'B1.
47 Oxygen Sensor - Controls the air-fuel mixture going
into the engine of vehicles equipped with three-way
catalytic converters. The sensor is coded '0', 'I1,
'2', '4' (unscrewed), or '7'.
-------
-69-
48 Carburetor Type - is coded 'S' (sealed plugs covering
mixture adjustment), 'F1 (fuel injection). 'A',
or '8'.
49 Limiter Caps - plastic caps on the idle mixture screws
to limit carburetor adjustments. The limiter caps
are coded '0', '!', '4' (tabs broken or bent), '7',
or '8' (sealed plugs removed).
Exhaust Gas Recirculation (EGR) System - directs a
portion of the exhaust gases back into the cylinders
to reduce NOX emissions in the exhaust gas. The
standard EGR configuration consists of a vacuum line
from the carburetor to a sensor (used to detect
engine operating temperature to activate the EGR
valve), and another vacuum line from the sensor to
the EGR valve.
50 EGR Control Valve - coded '0', 'I1, '3', '4', '?',
or '9' .
51 EGR Sensor - coded '0', 'I1, '3', '5', ' 7 ' .
52 Computer Systems and Related Sensors - computerized
engine and emissions control system which receives
input from various sensors for engine condition
information, and constantly adjusts the air/fuel
ratio, distributor, and emissions devices for optimum
economy, driveability, and emissions. The system
-------
-70-
is coded '0', '!', or '61. This variable includes the
entire computer system except for the oxygen sensor,
which is coded separately (see variable #47, Form A).
Form B - Rear
1-4 ID Number - Same as on Form A.
5-8 Make
9-12 Model
13 Vehicle Type - coded as follows: C = car, T = truck
14-15 License Plate - State abbreviation
16-19 Exhaust gas HC concentration (in ppm) at curb idle.
20-22 Exhaust gas CO concentration (in percent) at curb idle,
23-25 Odometer - mileage in thousands
26 Dash Label - displays the fuel required and is coded
'0'{for leaded vehicles), 'I1, or '7'.
27 Catalytic Converter - oxidizes the HC and CO to water
and C02 in the exhaust gas. Later model catalysts
also reduce oxides of nitrogen. The converter is
coded '0', 'I1, or '71 (entire catalyst canister
removed).
-------
-71-
28 Exhaust System - if as originally equipped an 'A1 is coded
If non-stock a "B1 is coded.
29 Exhaust System Integrity - the condition of the exhaust
system is coded 'I1 (no obvious leaks) or '9' (leaks
evident).
30 Tank Cap - seals the fuel tank during normal operating
conditions and is coded 'I1, '?', or '9' (loose cap).
31 Tank Label - displays required fuel and is coded '0'
(for leaded vehicles), '!', or '7'.
32 Filler Neck Inlet Restrictor - The restrictor is
designed to prevent the introduction of leaded fuel
into a vehicle requiring unleaded fuel. It is coded
'0' (for leaded vehicles), '!', '4' (widened), or '7'.
33 Plumbtesmo - Plumbtesmo paper is used to check for the
presence of lead in vehicle exhaust pipes. A positive
J.ndication is coded as 'P1 and a negative as 'N'.
34 Fuel Sample - indicates if inspector was able to obtain
fuel sample for later lead analysis ('Y' or 'Z').
-------
-72-
2. Classification Of Component Conditions
The table below was used to classify the various system
components as tampered (T), arguably tampered (A), or
malfunctioning (M). Only those codes which are applicable
to a given component are listed. Codes for 'not originally
equipped1 and 'functioning properly' are not included in
this table. Refer to Appendix B, Part 1 for an explanation
of the codes.
Codes from forms A and B
Component/system
Dash Label
Tank Cap
Tank Label
Filler Neck Restrictor
Catalytic Converter
Oxygen Sensor
PCV System
Heated Air Intake
Evaporative Control
System
Aspirated Air T T M
Injection System
Air Pump Belt T M
T = tampered
A = arguably tampered
M = malfunctioning
| 2 3 | 4 | 5 | 6 | 7 | 8
A
A
A
or T T •
T
T T T
T T T
T A A
rp wi rri rn fri
9 | B
M
M T
M T
M
-------
-73-
Codes from forms A and B
Component/system |2|3|4|5|6|7|8|9|B
Air Pump System
BGR Control Valve
EGR Sensor
T
T T
T T
T
T
T
M
M
-------
-74-
3. Fuel Sample Collection and Labeling Procedures
A fuel sample was taken from each vehicle requiring
unleaded fuel. These samples were collected in two-ounce
bottles with a hand-operated fuel pump. Once the sample was
drawn, the fuel was replaced with an equivalent amount of
unleaded fuel if the driver requested, and the pump was flushed
with unleaded fuel.
Each bottle was identified with an adhesive label that
had the vehicle identifying survey number on it. The vehicle
identifying number was the first entry on the data forms
described in Part 1 of Appendix B. The bottles were packed,
labeled, and shipped to EPA's Motor Vehicle Emissions Laboratory
in Ann Arbor according to the shipper's requirements.
-------
-75-
4. Plumbtesmo Application
1) Clean a portion of the inside of the tailpipe large enough
for the test paper by wiping it out with a paper towel or
cloth. This may be necessary to remove soot deposits
which might mask the color change.
2) Moisten the Plumbtesmo paper with distilled water and
immediately* press firmly against the surface to be tested
for approximately thirty seconds. If the tailpipe is hot
you may wish to clamp the test paper in the tailpipe
using a clean clamp.
*Note: The Plumbtesmo paper must be applied during the
time that the paper is yellow for the reaction to take
place. After approximately 15 seconds the yellow color
disappears and the paper is no longer effective. Excess
water also interferes with the reaction.
Care must be taken to avoid contamination of the test paper
If a person has recently handled a test paper with a
positive reaction, some lead or reactive chemical may
have been transferred to their fingers. Subsequently
handling a clean test paper may cause contamination.
3) After removing the test paper, determine whether a color
change has occurred. Red or pink coloration indicates
the presence of lead.
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5. Field Quality Control/Assurance
Reference and calibration gases were used to ensure the
accuracy of the emissions analyzer. Horiba gases certified by
RTF were used as reference gases. Two cylinders of reference
gas were used to validate the accuracy of the calibration gases
before they were taken to the field on each survey.
Three calibration gases (Horiba) were used. These gases
were a mixture of CO and HC in nitrogen and were used to check
the instrument at least three times daily. These calibration
gases were certified by the manufacturer and the RTF reference
gases. Their approximate compositions were:
8% CO
1560 ppm HC (Hexane equivalent)
4% CO
827 ppm HC (Hexane equivalent)
1.6% CO
320 ppm HC (Hexane equivalent)
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APPENDIX C
EMISSION CUTPOINTS FOR I/M AREAS
The table below lists the emission cutpoints used in 1986 by
the I/M areas covered in the 1986 tampering survey. The cut-
points for pre-1975 vehicles are not included, since these
vehicles were not surveyed.
Survey Site
St. Louis, MO
Memphis, TN
Pittsburgh, PA
Hartford, CT
Camden, NJ
Seattle, WA
Model Year
1975-79
1980
1981 +
1975-79
1980+
1981+
1975-79
1980
1981 +
1976-79
1980
1981+
1975-80
1981+
Emissions Cutpoints
CO (%) HC (ppm)
6.0
3.0
1.2
8.5
6.5
3.0
4.0
3.0
1.2
3.0
2.5
1.2
3.0
1.2
1975-78 3.0
1979+(no CC) 3.0
1979+(CC, 4 cyl.) 2.0
1979+(CC, 6-8 cyl.) 1.5
600
300
220
1990
1990
1990
400
300
220
300
275
220
300
220
800
600
300
300
KEY: CC = catalytic converter (all types), CYL. = cylinder,
OC = oxidation catalytic converter, AI = air injection,
TWC = three way catalytic converter.
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Survey Site
Los Angeles, CA
Tucson, AZ
Model Year
1975-79(no CC) 3.
1975-79(OC, no AI) 4
1975-79(OC, AI) 1.
1975-79(TWC) 1
1980+(no CC) 2,
1980+(OC, no AI) 2
1980+(OC, AI) 1.
1980+(TWC) 1
1975-78(4 cyl.) 2.2
1975-78(6-8 cyl.) 2.0
1979 (4 cyl.) 2.2
1979 (6-8 cyl.) 2.0
1980+ 1.2
Emissions Cutpoints
CO (%) HC (ppm)
5
5
5
5
5
5
2
0
200
250
150
100
150
150
150
100
250
250
220
220
220
KEY: CC = catalytic converter (all types), CYL. = cylinder,
-'OC -'oxidation catalytic converter, AI = air injection,
TWC = three way catalytic converter.
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