EPA-AA-IMS-81-12
Evaluation of the Applicability
of Inspection/Maintenance Tests
On A 1981 Cadillac Seville
With Throttle Body Fuel Injection
April 1981
Bill Smuda
NOTICE
Technical Reports do not necessarily represent final EPA decisions or
positions. They are intended to present technical analysis of issues using
data which are currently available. The purpose in the release of such
reports is to facilitate the exchange of technical information and to inform
the public of technical developments which may form the basis for a final EPA
decision, position or regulatory action.
Inspection/Maintenance Staff
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
U.S. Environmental Protection Agency
Ann Arbor, Michigan 48105
-------
ABSTRACT
This report presents test results which were gathered to determine the
suitability of existing I/M short tests on a Cadillac car with a computer
based emission control system. This car had a microprocessor-based engine
control system with throttle body fuel injection (TBI), modulated displacement
and a dual bed catalyst.
After suitable baselines were established, various components were made
inoperative in the emission control system. Complete FTP, HFET and I/M tests
were run for each vehicle condition. Also an on-board system diagnostic check
was performed for each configuration.
This report presents the measured data taken during the tests.
1.0 BACKGROUND
Beginning with the 1981 model year, electronics and computers control many of
the vital functions of automotive operation now regulated by mechanical
means. As the Inspection/Maintenance effort is expanded it is a prerequisite
that the test procedure used by Inspection/Maintenance programs be capable of
identifying 1981 and later model year vehicles with equipment failure and
parameter maladjustment. With the advent of the use of advanced electronics
into automobiles, it is necessary to evaluate the suitability of existing and
proposed I/M tests to these future automobiles. To accomplish this evalua-
tion, several prototype and early production cars containing representative
electronics of the future have been tested according to both the Federal Test
Procedures and I/M test procedures. The data obtained should indicate which
I/M test best suits these automobiles. This report presents the data
collected on the sixth such automobile tested by EPA, a 1981 Cadillac Seville
with a microprocessor controlled emission control system, throttle body fuel
injection (TBI), and modulated displacement. This is the first vehicle with
TBI tested in this series. Since TBI systems may see widespread use within
the next few model years, the results of the tests conducted on this vehicle
are of special interest.
2.0 HISTORY
The Cadillac Seville is a 1981 production vehicle rented from a local rental
firm. This particular vehicle which has a low altitude emission certification
was obtained from the rental agency on 2 February 1981 with 1144 miles on the
odometer. One day was allowed for vehicle preparation, and baseline testing
started on 4 February 1981.
After two baseline sequences were accomplished, the vehicle was tested with
eight different component deactivations. One final confirmatory baseline
sequence was then run. Testing was completed on 3 March 1981.
-------
3.0 TESTING PROCEDURE
In order to test the vehicle the following test sequence was used:
a. Federal Test Procedure (FTP) 1979 procedure, non-evaporative, no heat
build.
b. 50 MPH Cruise. This test consists of a three minute steady state run
at 50 MPH. HC and CO measurements are taken with a garage type analyzer.
This test is performed with the hood open and fan on. The three minute 50
MPH cruise also serves as preconditioning for the highway fuel economy
test.
c. Highway Fuel Economy Test (HFET). Immediately after the 50 MPH cruise.
d. On-Board System Diagnostic Check. This check took advantage of the
on-board self-diagnostic system used on 1981 GM products. See Attachment
3 for a description of the system.
Each of the following steps required a six minute idle preconditioning, hood
open, fan on.
e. Four Mode Idle Test with raw HC/CO garage type analyzer. Emissions
were tested at Idle (neutral), 2500 rpm, Idle (neutral), and Idle
(drive). The hood was open and the fan was on.
f. Loaded Two Mode. Raw HC and CO measurements were taken with the
dynamometer set at 9.0 A.H.P. at 30 MPH with the I.W. = 1750 pounds.
Immediately afterward, measurements were taken at idle (neutral) using a
garage type analyzer. The hood was open and the fan was on.
g. Propane Injection Procedure for three way catalyst vehicles. A
description of this test and a sample data sheet are given in Attachment 1.
Note: This propane injection procedure is still in the development stage.
Bear in mind when reviewing the obtained data that this is still an
experimental procedure.
%
I/M test HC and CO measurements were recorded before and after the dual bed
catalyst. A worksheet recording the I/M test results is shown in Attachment 2.
4.0 VEHICLE DESCRIPTION
The Cadillac used for this testing was a production vehicle with a low
altitude Emission Package. The most important components of this automobile's
emission control system were the sensors, actuators, and the microprocessor
unit. A complete description of these components is given in Attachment 3.
Attachment 4 lists specific vehicle parameters.
-------
5.0 BASELINE DATA
To accurately determine the effect of the various component deactivations, it
was necessary to have an accurate baseline determined for each pollutant in
each mode of every test type. This baseline data is displayed with the
component deactivation data.
6.0 TEST CONFIGURATIONS
After the baseline testing was completed, various components of the emission
control system were, one by one, deactivated prior to vehicle testing.
a. EGO Sensor Lead Disconnected and Open Circuited - Test numbers 80-7658
and 80-7659 were run with the exhaust gas oxygen (EGO) sensor dis-
connected. The EGO sensor supplies a voltage signal to the microprocessor
based on the oxygen content of the exhaust stream. ' By disconnecting this
sensor and leaving the lead open circuited the microprocessor senses a
near zero voltage and the closed-loop system is deactivated.
b. EGO Sensor Lead Disconnected and Short Circuited - Test numbers
80-7661 and 80-7662 were run with the exhaust gas oxygen (EGO) sensor
disconnected with the microprocessor input lead shorted. Shorting the EGO
sensor lead guaranteed a zero voltage input to the microprocessor. These
tests were designated EGO shorted.
c. Throttle. Position Sensor Disconnected - Test numbers 80-7663 and
80-7664 were run with the throttle position sensor (TPS) electrically
disconnected. This sensor provides the microprocessor with information
regarding the throttle blade angle. Disconnecting this device gives a
fixed closed throttle input to the microprocessor.
d. Coolant Temperature Sensor Disconnected Test numbers 80-7665 and
80-7666 were run with the coolant temperature sensor (CTS) disconnected.
Because the oxygen sensor does not perform properly until it reaches a
specified temperature, the coolant sensor informs the feedback control
system to operate in open-loop mode until temperature is reached. With
the CTS disconnected the system runs in an openloop mode.
^
e. Manifold Absolute Pressure Sensor Disconnected Test numbers 80-7667
and 80-7668 were run with the manifold absolute pressure sensor (MAP)
electrically disconnected. Disconnecting the MAP sensor sends a high
manifold pressure (low vacuum) signal to the microprocessor. A high
manifold pressure is indicative of a high load situation and consequently
the microprocessor provides additional fuel.
f. PROM Errors - Test numbers 80-7669 and 80-7670 were run with one PROM
(programmable read only memory) chip removed completely and the other PROM
chip installed with the aft pin row insulated from the computer. The
PROMs contain engine calibration data that is permanently retained and
programmed by the factory. Disabling the PROMs caused the vehicle to
operate with random unknown calibration.
-------
g. Throttle Position Sensor Shorted - Test numbers 80-7673 and 80-7674
were run with the IPS leads shorted. This sensor provides the micro-
processor with information regarding the throttle blade angle. Shorting
this device gives a fixed full open input to the microprocessor.
h. Manifold Air Temperature Sensor Disconnected - Test numbers 80-7675 and
80-7676 were run with the manifold air temperature sensor (MAT) electri-
cally disconnected. With the MAT open circuited the microprocessor senses
a low temperature signal.
7.0 TEST RESULTS
The test results are given in several attachments.
a. The FTP and HFET results are given in Attachment 5. The HC, CO, C02
and NOx readings are in grams/mile while fuel economy is in miles per
gallon. Two disablements, manifold absolute pressure sensor disconnected
and PROM errors, produced very high FTP HC and CO emissions.
b. Attachment 6 presents the standard I/M test data. Values are given for
readings taken before and after the catalyst. All I/M short tests were
able to identify the major FTP failures.
c. Attachment 7 presents the results of the propane injection diagnostic
procedure for three-way catalyst vehicles.
d. Attachment 8 presents the results of the on-board system diagnostic
check. In each case the trouble code output identified the induced
malfunction (diagnostic system inoperative indicates a PROM malfunction).
-------
ATTACHMENT 1
Description of the 3-Way Closed Loop
Propane Test Procedure
Vehicles shall be in a fully warmed-up condition prior to beginning this
procedure. Vehicles with manual transmissions will be tested in idle Neutral
only. Prior to the test, the vehicle shall be operated at 2500 rpm for two
full minutes.
This procedure will be performed in both Neutral and Drive gears for vehicles
with automatic transmissions. The entire procedure, steps 1-6, will first be
performed with the vehicle in Neutral gear. The vehicle shall then be
operated at 2500 rpm for two minutes, brought back to idle, and placed in
Drive gear for a repetition of steps 1-6.
Step 1: Present the propane flow rate to 4 CFH.
Step 2: With no propane flowing into the vehicle record idle RPM and idle CO.
Step 3: Induce propane to the air inlet of the carburetor and observe the
engine behavior.
a. If the engine RPM rises to a maximum value and then decreases,
record the maximum RPM value.
If the engine RPM value rises to a maximum value and continues to run
at that speed, record that RPM value. This RPM value will be the same
as the RPM value to be recorded in step 4.
b. If the engine RPM falls to a minimum value and then rises, record
the minimum value.
If the engine RPM falls to a minimum value and continues to run at
that speed, record that RPM value.
Note: The importance of closely observing the engine speed change immediate-
ly after induction of propane and until the engine speed stabilizes
cannot be overstressed. The success or failure of this procedure as
an I/M test key upon the ability of the technician to make a real time
observation of the behavior of the engine, observable in engine speed,
when propane is introduced.
An analog (meter type) tachometer must be used. A digital tachometer
will not shown maximum or minimum transient engine speeds.
c. Self explanatory
d. If engine dies terminate test at this point.
-------
e. If engine speed remains constant (neither rises nor falls)1 after
induction of propane record a yes value (1).
Step 4: When engine stabilizes (not to exceed 60 seconds) and with propane
flowing record idle RPM and idle CO.
Step 5: Withdraw the propane supply from the vehicle and observe the engine
behavior as in Step 3.
Step 6: When engine stabilizes (not to exceed 60 seconds) record idle RPM and
idle CO.
Note: If the engine behaves in an unusual manner add narrative comments in
the data sheet margins.
-------
PROPANE GAIN DATA SHEET
3-WAY CLOSED LOO?
IN
NEUTRAL
IN
DRIVE
STEP 1 PRESET FLOW RATE
*
STEP 2 RECORD: a) FLOW RATE
b) RPWI
c) IDLE%CO
STEP 3 INDUCE PROPANE, OBSERVE VEHICLE BEHAVIOR
RECORD ONE: a) RPM RISES SMOOTHLY TO .
b) RPM FALLS SMOOTHLY TO ;
c) ENGINE RUMS ROUGH AND THEN
STABILIZES (1-YES)
d) ENGINE DIES (1-YES)
e) RPM STAYS THE SAME (1-YES)
STF.P.', WHEN ENGINE STABILIZES, RECORD:
a) RPM
b) IDLE %CO
O
15
25
35
47
GO
10
01
20
30
44
O
G5
-------
3-V/AY CLOSED LOOP (Continued)
IN
NEUTRAL
IN
DRIVE
STEP 5
STEP 6
V/iTH DRAW PROPANE, OBSERVE VEHICLE BEHAVIOR
RECORD ONE: a) RPM RISES SMOOTHLY TO
b) RPM FALLS SMOOTHLY TO
-c) ENGINE RUNS ROUGH AND THEN
STABILIZES (1-YES)
d) ENGINE DIES (1-YES)
C) ft>\ uw$ Tilt
V/HEN ENGINE STABILIZES, RECORD:
\
a) RPM .
b) IDLE %CO
21
23
25
30
O
'.0
22
26
20
35
Q
P 2
80 i
-------
ATTACHMENT 2
DATE
DISABLEMENT
DISABLEMENT TESTING - SHORT TEST DATA SHEET
TEST NO. ' VEHICLE
OPERATOR
Before
Catalysts
After
Catalysts
50 MPH Cruise
4 Speed Idle
Idle (N)
2500 RPM
Idle (N)
Idle (M)
2 Mode Loaded
Loaded*. (Pendant Mode)
Idle (N)
HC CO
HC
CO
* The loaded mode is a 30 mph cruise @ 9.0 AHP.
-------
ATTACHMENT 3
DIGITAL FUEL INJECTION
GENERAL DESCRIPTION
The Digital Fuel Injection (DPI) is a speed density fuel
system that accurately controls the air/fuel mixture into the
engine in order to achieve desired performance and emission
goals. The Manifold Absolute Pressure sensor (MAP),
Manifold Air Temperature sensor (MAT), and the
Barometric Pressure sensor (BARO) are used to determine
the' density (amount) of air entering the engine. The HEI
distributor provides engine speed information (P>.PM), see
Figure 6C-65. This information is fed to the Electronic
Control Module (ECM), and the ECM performs high speed
digital computations to determine the proper amount of fuel
necessary to achieve the desired air fuel mixture. Once the
ECM has calculated how much fuel to deliver, it signals the
fuel injectors to meter the fuel into the throttle body. When
the combustion process has been completed, some
hydrocarbons (HC), carbon monoxide (CO), and nitrous
oxides (NOx) result; therefore, each DPI engine has an
emission system to clean these gases out of the exhaust
stream. The. catalytic converter converts these gases into
more inert gases, however, the conversion process is most
efficient (l°wer emission levels) at an air/fuel mixture of
14.7/1. - -
Since the ECM controls the air/fuel mixture by
metering fuel, the ECM would be more accurate if it could
check its output and correct the air/fuel mixture for.
deviations from the ideal ratio of 14.7/1. The oxygen sensor
monitors these exhaust gases and sends the information to
the ECM which decides if any corrections are necessary.
This correction process is known as closed loop operation.
Because a vehicle is driven under a wide range of operating
conditions, the ECM must provide the correct quantity of
fuel under all operating conditions. Therefore, additional
sensors and switches are necessary to determine what
operating conditions exist so that the ECM can provide an
acceptable level of driveability under all operating
conditions. See Figure 6C-66 for a component diagram.
In summary, closed loop DFI operation provides
acceptable levels of driveability and fuel economy while
improving emission levels.
DFI SUBSYSTEMS .
The following subsystems combine to form the DPI
closed loop system:
1. Fuel Delivery .
2. Air Induction
/ 3. Data Sensors .-.- .
'-' 4. Electronic Control Module (ECM)
5. Electronic Spark Timing (EST)
' 6. Idle Speed Control (ISC) ..-.-..'
-------
rudL o » o i
DIGITAL FUEL INJECTION/CLOSED LOOP
ECM
PHASE II (3-WAY)
CATALYTIC CONVERTER
THROTTLE
BODY
INJECTORS
SENSOR EXHAUST
CHARACTERISTIC
3-WAY CONVERTER
CHARACTERISTICS
VOLTAGE
RICH A/F LEAN
RATIO
RICH A/F LEAN
RATIO
Figure 6C-65 Closed Loop DPI Operation
7. Emission Controls
8. Closed Loop Fuel Control
9. System Diagnostics
10. Cruise Control
11. Modulated Displacement (MD)
Each subsystem is described in the following
paragraphs.
1. Fuel Delivery System
Figure 6C-67 shows the various components which
comprise the fuel delivery system. The fuel is pumped from
the fuel tank through the supply line and through the fuel
filter to the throttle body. The throttle body contains the
pressure regulator which regulates fuel pressure to a
nominal value of 10.5 psi and the fuel injectors which meter
the fuel into the throttle body. The injectors are located
above the throttle blades and direct atomized fuel into the
throttle bores. The ECM controls the timing and the
amount of fuel injected into the engine. Any excess fuel is
returned to the fuel tank through the fuel return lines,
a. Fuel Pump
An electric motor driven twin turbine type pump is
integral with the fuel tank float unit, and the fuel pump
supplies fuel to the throttle body at a positive fuel pressure.
The pump is not repairable; however, the pump may be
serviced separately from the fuel gage unit.
The ECM controls the operation of the fuel pump by
activating the fuel pump relay located in the relay panel.
When the ignition is placed in the on or start position, the
fuel pump is turned on. If'ihe engine is not cranked within
one second of turning the ignition on, the fuel pump is
turned off. The fuel pump circuit is protected by a 10 amp
fuse located in the mini fuse block.
b. Fuel Tank
The fuel tank incorporates a reservoir directly below
the pump assembly. The "bath tub" shaped reservoir
ensures a constant supply of fuel for the fuel pump even
when the fuel is low or when severe maneuvering conditions
arc encountered. .
c. Fuel Filter
The fuel filter consists of a casing which encloses a
paper filter element. .The filter element is capable of filtering
foreign particles of the 10 micron size out of the fuel. The
filter element is a throwaway type and should be replaced
(AC type GF-157 or equivalent) as described in the Vehicle
Maintenance Schedule. The filter is mounted on the frame
near the left rear wheel.
d. Fuel Pressure Regulator
The fuel pressure regulator, Figure 6C-68, is ari
integral part of the throttle body. The valve, which regulates
pressure, is a diaphragm-operated relief valve in which one
side of the valve senses fuel pressure and the oilier side is
exposed to atmospheric pressure. Nominal pressure is
established by the pre-load of a spring. The fuel pressure
regulator maintains a constant pressure drop across the
injectors. Fuel in excess of that used to maintain a constant
pressure drop is returned through the fuel return line to the
fuel tank. The. regulator is serviced as part- of the fuel
metering assembly.
-------
-n
ta
c
3
O5
O)
C5
-n
o
:i
o
'2'
3
n
CtJ*
Cu
3
THiRD
GEAR
SWITCH
CRANK
SENSOR.
THROTTLE
POSITION
^cNjcon
COOLANT
TEMPERATURE
SENSOR
MANIFOLD AIR
BAROMETRIC
PRESSURE
SENSOR
MANIFOLD AIR
PRESSURE
SENSOR
AIR CONDITION
CLUTCH
SWITCH
BRAKE
SWITCH
DRIVE
SWITCH
REVERSE
SWITCH
IGNITION
SWITCH
OXYGEN
SENSOR
N
^
1
:-
.,
\
J
J
1901 DIGITAL FUEL INJECTION
INPUTS OUTPUTS
THROTTLE
y' '" IDLE SPEED
CONTROL
(ISC) ^
'"' MIUES PER RANGE
MPG RESET ((vlPG) |
DI1G REO ELECTRONIC DATA
,, ' CLIMATE CONTROL ' . RANGE
(ECC) MODULE { f
- BYPASS
DIST. REF. HEI ^
/^. " ' MODULE SHAHK IIMING
ELECTRONIC CONTROL MODULE (ECM)
j
- V ^ INPUT/OUTPUT (I/O) ' "\
, i >- >
CENTRAL PROCESSING UNIT
(CPU)
>- POWER SUPPLY (P/S)
^. . .
. 1 '*' DATTERY
,
X-
^
1
' 1
v
CRUISE
CONTROL
SOLENOID
CANISTER
PURGE ' .
A 1 R
MANAGEMENT
SOLENOIDS
CRUISE .
CONTROL
SOLENOID
SET
TIMING ,
EGR
SOLENOID
- CHECK
ENGINE
COOLANT .
OVERTEMP
MODULATED
DISP.
DRIVEH
ASSEMBLY
FUEL PUMP
1'
1
INJECTOR B
SELECT
col FMDin"?
-------
FUEL BOWL RESERVOIR
-COVER ,INJECTOR
VALVE
DIAPHRAGM
FUEL
INLET
FUEL METERING BODY
Figure 6C-68 Fuel Pressure Regulator
ELECTRICAL
TERMINALS
CORE PIECE
BALL VALVE
J^*ELECTRICAL
TERMINALS
SOLENOID
COIL
FUEL IN
VALVE SEAT
'CORA V^
'PATTERN \-ATOMIZER
Figure 6C-69 Fuel Injectors - DPI
information to the ECM. The sensor is a thermistor whose
resistance changes as a function of temperature. When the
temperature is low, the resistance is high and the resistance
decreases as the temperature increases. ' '
b. Coolant Temperature Sensor
The coolant temperature sensor is similar in function
to the MAT sensor and is installed in the right front corner
of the engine directly below the thermostat. This sensor
provides coolant temperature information to the ECM for
fuel enrichment, ignition timing, EGR operation, canister
purge control, air management, EFE operation, closed loop
fuel control, and modulated displacement.
c. Manifold Absolute Pressure Sensor {IV1AP)
The Manifold Absolute Pressure (MAP) Sensor
monitors the changes in intake manifold pressure which
result from engine load and speed changes. These pressure
changes are supplied to the ECM in the form of electrical
signals. As intake manifold pressure increases, additional
fuel is required. The MAP sensor sends this information to
the.ECM and the ECM increases the injector .on time (or
pulse width). Conversely as manifold pressure decreases, the
pulse width will be shortened. The MAP sensor is mounted
under the instrument panel near the right-hand A/C outlet
and is connected, electrically to the ECM. A hose from the
throttle body provides a signal to the sensor.
d. Barometric Pressure Sensor (BARO)
This unit senses ambient or barometric pressure and
provides information to the ECM on ambient pressure
changes due to altitude and/or weather. The sensor is
mounted under the. instrument panel near the right-hand
A/C outlet and it sends an electrical signal to the ECM. The
sensors' atmospheric opening is covered by a foam filter.
e. throttle Position Sensor (TPS)
The Throttle Position Sensor is a variable resistor
mounted on the throttle body and is connected to the
throttle valve shaft. Movement of the accelerator causes the
throttle shaft to rotate, and throttle shaft rotation opens or
closes the throttle blades. The sensor determines shaft
position (throttle angle) and transmits the appropriate
-------
!'.. Fuel. Injectors
1 , The two injector valves are electronically actuated and
:.,e;eT the facl into the throttle body above the throttle
.-lades, sec Figure 6C-69. The valve body contains a
.-olenoid whose plunger or corepiece is pulled upward by the
olefioid coil. When the solenoid coil is energized, the
vhtrsaer is raised and the spring pushes the ball valve away
from the valve seat. Fuel flows through the valve. Since the
pressure regulator maintains a constant pressure drop across
the injectors, the quantity of fuel injected is determined by
how long the valve is held open.
f. Fuel Unas
A 3/8" fuel delivery line is routed along the left frame
side rail between the fuel pump/sending unit assembly and
;he throttle body. A teflon hose covered with braided
stainless steel is used to provide high system integrity and
protection against abrasion.
The fuel return line is 5/16" in diameter and is routed
along the right frame side rail. This line is also teflon hose
covered with braided stainless steel.
2. Air Induction System
Air for combustion enters the throttle body and is
distributed to each cylinder through the intake manifold. A
special distribution skirt is added to the throttle body
assembly directly below each fuel injector to improve fuel
distribution from the injector to the intake manifold. The
nir flow rate is controlled by the throttle valves which arc
connected to the accelerator pedal linkage, icne speeu u.
determined by position of the throttle valves and is
controlled -by the Idle Speed Control (ISC).
a. Throttle Body
The throttle body consists of a housing with two bores
and two throttle blades mounted on a common shaft. One
end of the throttle shaft connects to the accelerator pc-c'al
by means of mechanical linkage and the other end of the
throttle shaft connects to the throttle position sensor. Skirts
which are shaped like inverted cones have been added to the
bores in order to improve fuel mixing and distribution.
b. Intake Manifold
The aluminum single plane intake manifold is designed
especially for DPI engines with MD. The EFE heat riser
system requires the use of an exhaust heat crossover passage.
Refer to Section 6E of the Service Manual for a description
of EFE operation.
3. Data Sensors
The component diagram ( Figure 6C-66) lists the data
sensors and illustrates how the data sensors are interrelated.
Each data sensor will be described below: . -
a. Manifold Air Temperature Sensor (MAT)
The Manifold Air Temperature (MAT) sensor is
installed in the intake manifold in front of the throttle body.
This sensor measures the temperature of the fuel/air
mixture in the intake manifold end provides this
THROTTLE
BODY WITH
FUEL INJECTORS
AND PRESSURE .
REGULATOR
FUEL PUMP&
SENDING UNIT
FUEL FILTER
Figure 6C-G7 Fuel Supply System
-------
6C-40 ENGINE FUEL SYSTEM
electrical signal to the ECM. The ECM processes these
signals and uses the throttle angle information to operate
the idle speed control system and to supply fuel enrichment
as the throttle blades are opened.
f. Vehicle Speed Sensor
The vehicle speed sensor informs the ECM as-to how
fast the vehicle is being driven. The ECM uses this signal
for the logic required to operate the MPG sentinel, the
integral Cruise Control, the modulated displacement
feature, and the idle speed control system.
The speed sensor produces a weak signal. Therefore, a
buffer amplifier is placed between the speed sensor and the
ECM to amplify the speed signal. The speed sensor and the
buffer amplifier are located behind the speedometer cluster.
Additional information on the speed sensor can be found
under the Cruise Control section of this Service Manual and
the 1980 Service Manual. .- .
g. Oxygen Sensor
The oxygen sensor used in the DPI system consists of
a closed end Zirconia sensor placed in the engine exhaust
gas stream. This sensor generates a very weak voltage which
varies with the oxygen content of the exhaust stream. As
the oxygen content of the exhaust stream increases relative
to the surrounding atmosphere, a lean fuel mixture is
indicated by a low voltage output; as the oxygen content in
the exhaust stream decreases, a rich fuel mixture is indicated
by a rising voltage output from the sensor.
When the oxygen sensor is warm (above 200'Q, the
output voltage swings betsveen 200 millivolts (lean mixture)
and 800 millivolts (rich mixture). However, when the
oxygen sensor is cold (below 200°C).
NOTICE: No attempt should be made to measure the
oxygen sensor output voltage, as the current drain of
any conventional voltmeter would be enough to
permanently damage the sensor, shifting its calibration
range and rendering it unusable. Similarly, no jumpers,
test leads, or other electricai connections should ever
be made to the sensor, but only, to the harness after
disconnection from the sensor. The oxygen sensor has
a permanently connected pigtail, with a Weatherpack
environmental connector joining it to the engine
control harness.
h. Engine Speed Sensor (Distributor)
The engine speed signal comes from the seven terminal
HEI module in the distributor. Pulses from the distributor
are sent to the ECM where the time between these pulses
is used to calculate engine speed. The ECM adds spark
advance modifications to the signal and sends this signal
back to the distributor.
4. Electronic Control Module (ECM)
The Electronic Control Module monitors and controls
all DFI system functions. The switches and data sensors
which the ECM monitors are listed in Figure 6C-66. The
data sensors supply analog signals to the ECM and the
input/output devices convert these signals to digital signals.
The signals must be in digital format because the central
processing unit can only manipulate digital information.
The Central Processing Unit (CPU) is the brain of the ECM
and the CPU performs all mathematical computations and
logic functions necessary to deliver the proper air/fuel
mixture. The CPU also calculates spark timing and idle
speed and it commands the operation of the emission
systems, closed loop fuel control. Cruise Control,
diagnostics, and modulated displacement. The CPU can
accomplish all of these functions by following the
instructions which have been programmed into the memory
of the ECM.
There are three types of memory in the ECM:
1. Read Only Memory (ROM)
2. Random Access Memory (RAM)
3. Programmable Read Only Memory (PROM)
When ROM memory is programmed, the program .
cannot be changed and information can only read from the
memory. If battery voltage is lost, the instructions in ROM
memory will be retained.
Random access memory is the scratch pad for the CPU.
Information can be read into or out of RAM memory hence
it is called scratch pad memory. Engine sensor information,
diagnostic codes, and the results of calculations are
temporarily stored here. If the battery voltage is removed,
all the information in RAM memory is lost (similar to a
hand held calculator when the switch is turned oft}.
Programmable Read Only Memory (PROM) contains
engine calibration data for each engine, transmission, body,
and rear axle ratio. PROM will always retain this
. information permanently even if battery voltage is removed,
and it can be programmed by the factory easily. These
memory devices are removable from the ECM.
To demonstrate how the ECM operates, the events
which occur when the ignition switch is turned on will be
listed:
1. The ECM receives the ignition ON signal.
2. The Fuel Pump is activated by the ECM. (The pump
will operate for approximately one second only, unless the
engine is being cranked or has started).
3. All engine sensors are activated and begin
transmitting signals to the ECM.
4. The EGR solenoid is activated to block the vacuum
signal to the EGR valve.
5. The "check engine" and "coolant" lights are
illuminated as a functional check of the bulb and circuit.
6. The HEI bypass line is pulled down to 0 volts.
The following events occur when the engine is cranked.
1. The 12 volt crank signal is sent to the ECM.
2. The fuel pump is operating.
3. After a short prime pulse, injectors alternately
deliver a fuel pulse on each distributor reference pulse.
^
4. The engine sensors continue to transmit signals to
the ECM.
5. The other events are similar to the events which
occur when the ignition is on.
The following events occur when the engine starts.-
1. The crank signal is removed from the ECM.
2. The injectors deliver fuel pulses alternately for each
distributor reference pulse.
3. The HEI bypass line is pulled up to 5 volts and the
HEI module receives spark advance signals from the ECM.
4. The ISC motor begins to control idle speed if the
throttle switch is closed.
-------
a./
,.. ENGINE FUEL SYSTEM 6C-41
5. The fuel pump operates continuously.
6. The pressure regulator maintains fuel pressure at
10.5 psi by returning excess fuel to the fuel lank.
7. The other events are similar to the events which
occur v/hen the ignition is on.
The ECM's control of fuel delivery can be considered
in three basic modes: cranking, normal operation, and wide
open throttle. If the 12 volt cranking signal indicates that
the engine is cranking, injectors alternately deliver a fuel
pulse for every distributor reference pulse. However, if the
engine should flood, smaller alternating fuel pulses are
delivered if the throttle is held open and if cranking exceeds
approximately 3 seconds.
When the cranking signal is removed, the injectors
deliver fuel pulses alternately for every distributor reference
pulse. The ECM adjusts the injector pulse width to account
for operating conditions such as idle, part throttle,
acceleration, deceleration, and altitude.
The MAP, I3ARO and TPS sensors inform the ECM
that a wide open throttle condition occurred and the ECM
supplies additional fuel enrichment.
5. Electronic Spark Timing (EST)
The Electronic Spark Timing system consists of the
ECM and a modified HEI distributor which use a 7 terminal
HEl module. The HEI distributor is designed to provide
high secondary output voltages to the spark plugs and is a
maintenance free unit. The HE! distributor communicates
to the ECM through a 4 terminal connector which contains
four circuits. These four circuits are:
1. The Distributor reference circuit
2. The bypass circuit
3. The EST circuit
4. The ground circuit
Whenever the pickup coil signals the HEI module to
open the primary circuit, it also sends the spark timing
signals to the ECM through the reference line.
When the voltage on the HEI bypass line is 0 volts
(engine cranking), the HEI module is forced into bypass
mode which means that the HEI module provides of spark
advance at buse timing and disregards the spark advance
signal from the ECM. If the voltage on the HEI bypass line
is 5 volts (engine running), the HEI module accepts the
spark timing signal provided by the ECM.
.The ECM monitors engine speed through the HEI
reference line and engine operating conditions through the
data sensors, and then the ECM calculates the proper spark
advance from these parameters. The spark advance is
supplied to the HEI distributor through the EST line.
6. Idle Speed Control (ISC)
The idle speed control system controls the engine speed
when the throttle switch is closed. The idle speed control
system includes the electric actuator (ISC motor), the idle
switch (throttle switch), and the ECM. The ISC motor is
a DC reversible motor which has the throttle switch as an
integral part of the ISC motor plunger, see Figure 6C-70.
The throttle lever rests against the ISC motor plunger which
extends and retracts to change the throttle blade angle. The
position of the idle switch determines whether the ISC
motor slMukl control the idle ^pecd or not. When the switch
is closed by the throttle lever resting against the end of the
plunger, the ECM issues the appropriate commands to the
ISC motor in order to maintain the programmed idle speed.
The ECM monitors the data sensors to determine when to
increase or decrease throttle blade angle. When the throttle
lever moves away from the ISC motor plunger, the throttle
switch opens and the ECM stops sending idle speed
adjustments to the ISC motor because the driver is
controlling the engine speed. When the engine is shut off,
the ISC motor fully extends its plunger and opens the
throttle blades so that the idle speed will be fast enough to
start the car. When an engine is cold, the ECM holds the
throttle valve open for a longer period of time to provide
faster warmup time.
Figure 6C-70 Idle Speed Control Actuator (iSC)
7. Emission Controls
a. EGR Operation
The ECM controls the operation of the EGR system.
Whenever the EGR solenoid is energized by the ECM, the
EGR system is disabled (no exhaust gas is recirculated
through the intake manifold). When the EGR solenoid is
cleenergized, the EGR system is enabled and exhaust gas is
recirculated through the intake manifold.
Refer to Section 6E and SD of the Service Manual for
additional information about the operation of the EGR
system.
b. Air Management Operation
The ECM controls the operation of the air management
system. The air pump delivers air to the divert (control)
valve which sends the air to the air cleaner or the switching
valve. The switching valve sends the air either to the
catalytic converter or the exhaust ports of the engine,
When the engine is cold, the air is sent to the exhaust
ports of the engine. The ECM energizes tho air control and
air switching solenoids by supplying ground signah to the
solenoids. The air flows through the divert (control valve)
a;\d the switching valve to the exhaust ports.
When the engine is warm and operating normally,"the
air is sent to the catalytic converter. The ECM energizes the
divert solenoid by supplying a ground signal to the divert
solenoid and deenergix.cs the switching solenoid, by
removing the ground signal to the solenoid. The air Hews
through the divert (control) valve (solenoid e;;,ergi7ed) ?.:-.d
the switching valve (solenoid deencrgi/ec!) to '.he ca-nlytic
converter. . -. . .
-------
,6C-42 ENGINE FUEL SYSTEM
When the engine is decelerating quickly, the air is sent
(diverted) to the air cleaner to prevent backfiring. The ECM
deenergizes the divert solenoid by removing the ground
signal to the divert solenoid. The air flows through the divert
valve (solenoid deenergized) to the air cleaner. .
c. Canister Purge Control Operation
The ECM controls the operation of the canister purge
control system. When the engine is cold, there is no vacuum
to the canister control line. The ECM energizes the canister
purge control solenoid by supplying a ground signal to the
solenoid. When the solenoid is energized, the vacuum to the
canisP.T purge control line is blocked.
When the engine is at normal operating temperature,
vacuum is supplied to the canister purge control solenoid.
The ECM deenergizes the canister purge control solenoid
by removing the ground signal to the solenoid. When the
solenoid is deenergized, the vacuum is supplied to the
canister purge control.
8. Closed Loop Fuel Control
The purpose of closed loop fuel control is to precisely
maintain an air/fuel mixture of 14.7/1. When the air/fuel
mixture is maintained at 14.7/1, the catalytic converter is
able to operate at maximum efficiency which means lower
emission levels. Since the ECM controls the air/fuel
mixture, it needs to check its output and correct the fuel
mixture for deviations from the ideal ratio. The oxygen
sensor .feeds this output information back to the ECM.
9. Syytem Diagnostics
The DPI diagnostic routine has four types of tests
which may be utilized if the situation warrants it. These four
tests arc:
1. The engine malfunction tests
2. Switch tests
3. Engine data displays
4. Output cycling tests
"!'!.: engine malfunction tests detect system failures or
abnorm/iities. When these malfunctions occur, the ECM
will turn on the amber "check engine" light located in the
right hand information center, see Figure 6C-71. The
corresponding trouble codes will be stored in the ECM's
memory. If a data sensor fails, the ECM substitutes a failsoft
value into its calculations and continues to operate the
engine with this nominal value. In this mode, there may or
may not be some loss of driveability. If the fault should clear
up, then the check engine light turns off, but the trouble
code remains. This condition is known as an intermittent
failure. The digital display panel of the Eleclronic Climate
Control will display on command any of the trouble codes
which may have been stored in the ECM.
The switch tests check the operation of various switches
which provide inputs to the ECM. During this test series,
the technician cycles certain switches and the ECM analyzes
this action to determine if the switches are operating
properly.
The engine data series displays important engine data
information. The technician should compare this
infoiiniuioii to the information generated by an engine
which is operating properly.
The output cycling series cycles various ECM outputs
on an olT. During this test series, the technical! can check
the operation of the engine control solenoids and lamps by
using command signals originating from the ECM.
Sec Section 6D for Electronic Diagnosis - Computer
Controlled.
Figure 6G-71 "Check Engine" Light
10. Modulated Displacement (MD)
Modulated Displacement (MD) is an
electromechanical system which deactivates certain engine
cylinders in order to save fuel. Since the basic operation of
the MD engine is similar to the closed loop DFI engine, only
the modulated displacement feature will be discussed in this
section, sec Figure 6C-72.
The following general operating conditions must be met
before the ECM will disable certain cylinders:
A. Coolant temperature must be above 48°C
B. The transmission must be operating in 3rd gear
C. The vehicle must be moving faster than 24 mph
D. Engine speed must be below 2,600 rpm
E. Code 25 cannot be set
The ECM controls cylinder selection indirectly
throughout the Modulated Displacement Amplifier
(MDA), and the Modulated Displacement Amplifier
(MDA) switches the cylinder selector solenoids on and off..
When the cylinder solenoids are enabled, the mechanical
valve selector body will close the intake and exhaust valves
of that particular cylinder, and the ECM automatically
reduces the amount of fuel delivered to the engine and alters
the spark timing.
The cylinder selector solenoids require an initial pull
in current of four amps and later require a hold in current
of one amp. This is more amperage than the ECM can
handle. Therefore, the Modulated Displacement Amplifier
(MDA) is connected between the ECM and the solenoids
to supply additional power and to perform the switching
function. During 6 cylinder operation, the MDA deactivates
cylinders ^il and ±:4 (solenoids energb-d), and during 4
cylinder operation, the MDA deactivates cylinders i:6 and
7 in addition to cylinders ~ 1. and 4 (solenoids
energized). Six cylinder operation only occurs above 47
mph.
-------
-s by
niter
The L7.CM monitors the MDA to determine if cylinder
selection is actually occurring. The MDA supplies a 12 volt
feedback signal to the ECM when the MDA is operating
in 8 and 6 cylinder mode; the MDA supplies a.volt feedback
.signal to the ECM when the MDA is operating in 4 cylinder
mode. If the MDA feedback signal is not correct, then the
ECM sets a check engine light and code 25 because the
cylinder selection process is not operating properly. Refer
to Section 6A of the Service Manual for more information
on the mechanical operation of the cylinder selector vahes.
an
>>c met
CLOSED LOOP DIGITAL FUEL INJECTION Y>.'[TH MODULATED DISPLACEMENT
. 10 PSI
'FUEL INJECTORS
ENGINE
SENSORS
i
J
THROTTLE
BODY
INJECTORS
IN-TANK
TWIN TURBINE
FUEL PUMP
PHASE II
CONVERTER
BLOCKING
PLATE
MANIFOLD
ABSOLUTE
PRESSURE
(MAP)
Figure 6C-72 Closed Loop DPI With Modulated Displacement
-------
6D-64 ENGINE ELECTRICAL
ENVIRONMENTAL
BULKHEAD CONNECTOR
CENTER
BULKHEAD
CONNECTOR
M-D
SOLENOID
#6
TO LOW
PRESSURE
SWITCH
M-D
SOLENOID
M-D
SOLENOID
#2
TO A.I.R.
SWITCH
VALVE
TO A.I.R.
.CONTROL VALVE
GROUND WIRE
REFER TO
FIGURE 4
TO AIR
CONDITIONER
COMPRESSOR
TO COOLANT
TEMPERATURE
SENSOR WIRE
ASSEMBLY
REFER TO
VIEW D
TO M.A.T.
SENSOR
TO CANISTER PURGE
M-D REFER TO VIEW E
SOLENOID
#1 FRONT OF CAR
NEGATIVE
BATTERY
CABLE
GENERATOR
GROUND\ ASSEMBLY
WIRE
TO GENERATOR
TO POSITIVE
BATTERY
CABLE
VIEW A
TO CRUISE CONTROL
SERVO ASSEMBLY
TO ENGINE METAL
o ^ , r. i TEMPERATURE
V1RE * WARNING SWITCH
REFER TO
FIGURE 2
INJECTOR CONNECTORS
TO UNDERHOOD LAMP
ASSEMBLY
TO CRUISE jgy^SZzz.
CONTROL V?£p.
VACUUM
VALVE:
ASSEMBLY/ CENTER" BULKHEAD TO OIL
CONNECTOR PRESSURE
ENVIRONMENTAL SWITCH
BULKHEAD
CONNECTOR
FRONT OF CAR
TO ENGINE STARTING
MOTOR
REFER TO FIGURE 5
TO E.C.C. BLOWER
MOTOR FEED
FUEL PUMP
DIAGNOSTIC
CONNECTOR
FRONT OF CAR
FIGURE 1
CRUISE CONTROL
SERVO ASSEMBLY
£m7^-^?^:s.-~
'./.
!:!,'/
ENGINE
STARTING
MOTOR
FRONT OF CAR
FIGURE 5
Fiiji:re 60-73 DFI/MD Engine Wiring Assembly (A)
-------
TO DISTRIBUTOR
TO I.S.C. MOTOR AND
THROTTLE SWITCH
SET-TIMING
CONNECTOR
VIEW C
COOLANT TEMPERATURE
SENSOR WIRE ASSEMBLY
TO THROTTLE
POSITION SENSOR
TO E.G.R.
SOLENOID ~
(NATURAL)
- "--^-i ^rff^'-,'^f-:'~-fr-y^'^P'.
TO M.A.T.
SENSOR
TO ENGINE METAL
TEMPERATURE
WARNING SWITCH N.I
OXYGEN SENSOR
T.P.S.
DIAGNOSTIC
CONNECTOR
TO CANISTER PURGE
SOLENOID (RED)
FRONT OF CAR \Jy^'
C \
FRONT OF CAR
TO TRANSMISSION
THIRD-GEAR SENSOR
VIEW E
fviEW~F~]
LH BULKHEAD
CONNECTOR
A.I.R. VALVE
BRACKET
ASSEMBLY
GROUND WIRE
TO WINDSHIELD
WASHER
SOLVENT
LEVEL SENSOR
f. SWITCH
PANEL
FRONT OF CAR
FIGURE 4
[FIGURE s |
J
Figure 6D-74 DFIA4D tncjine Wiring Assembly (F.)
-------
nr
P 8 F"
LLE
ALL NEW G.M. VEHICLES ARE CERTIFIED BY THE
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
AS CONFORMING TO THE REQUIREMENTS OF THE
REGULATIONS FOR THE CONTROL OF AIR POLLUTION
FROM NEW MOTOR VEHICLES. THIS CERTIFICATION IS
CONTINGENT ON CERTAIN ADJUSTMENTS BEING SET TO
FACTORY -STANDARDS. IN MOST CASES, THESE
ADJUSTMENT POINTS EITHER HAVE BEEN PERMANENTLY
SEALED AND/OR MADE INACCESSIBLE TO PREVENT
INDISCRIMINATE OR .ROUTINE ADJUSTMENT IN THE
FIELD. FOR THIS REASON, THE FACTORY PROCEDURE FOR
TEMPORARILY REMOVING PLUGS, CAPS, ETC. FOR
PURPOSES OF SERVICING THE PRODUCT MUST BE
STRICTLY FOLLOWED AND, WHEREVER PRACTICABLE,
RETURNED TO THE ORIGINAL INTENT OF THE DESIGN.
T* A F"9 H r~ lOi IT" rf""* ff~\ F« 8 T" P" Pi 8 T" O
TABLE Or COiMTEm S:
Subject
GENERAL DESCRIPTION
Digital Fuel Injection (DFI)...
Computer Command Control.
8D-I
SD-130
DIGITAL FUEL INJECTION (DPI)
DIAGNOSIS
"TROUBLE CODES"
The diagnostic charts in this manual are selected on the
basis of trouble codes which can be displayed during the
diagnostic readout. Steps of a "tree", which require testing
or explanation, are described on the succeeding pages. These
paragraphs are keyed to the correct steps in the "tree" by
the circled number.
When certain circuits need to be checked, a schematic
diagram is included, and reference to a "circuit number" is
niadc. The circuit number (410, 575, etc.) is shown inside
the box which represents the connector body in the complete
circuit diagram.
Trouble codes programmed into the DFI ECM arc
listed i-.nd identified in Figure SD-1.
INTERMITTENT PROBLEM DIAGNOSIS
DIAGNOSTIC CHARTS CANNOT BE USED TO
DIAGNOSE INTERMITTENT FAILURES. The testing
^quired ;it various points of the chart depends upon the
|p-iili being present to locate the problem. If the fault is
tent, (not present continually), an unnecessary
rqihiccmcnt will be indicated and the problem may
remain.
Since many intermittent problems are caused at
electrical connections, diagnosis of intermittent problems
should start with a visual and physical inspection of the
connectors involved in the circuit. These connectors, should
be disconnected, examined, and reconnected before
replacing any components of the system. Some causes of
connector problems are:
1. Improperly formed terminals or connector bodies.
2. Damaged terminals or connector bodies.
3. Corrosion, body sealer, or other foreign matter on
termii
terminals.
the terminal mating surfaces which could insulate the
4. Incomplete mating of the connector halves.
5. Terminals not fully seated -in the connector body
("backed-out" terminals).
6. Terminals not tightly crimped to the wire.
If an affected circuit is one that may be checked by the
switch tests, the out put cycling tests, or engine dai a displays,
make the check on the appropriate circuit. If the
intermittent code is a code 33, a special procedure must be
followed. Refer to the procedure labeled 33A -iriu-rmiitent
MAP/BAKO Sensor correlation test. If the intermittent
-------
code is code 13, 44, or 45, use the diagnostic chart for
code 13, 44, or 45 because these particular charts have
been designed to account for intermittents.
"TROUBLE CODE" DIAGNOSIS
The following abbreviations will be used in this section:
IPS.- Throttle Position Sensor
ECM - Electronic Control Module
ISC - Idle Speed Control (includes Idle Speed Motor
and Throttle Switch)
HEI -.High Energy Ignition
MAP - Manifold Absolute" Pressure (Sensor)
BARO - Barometric Pressure (Sensor)
ECC - Electronic Climate Control
MAT - Manifold Air Temperature (Sensor)
CTS - Coolant Temperature Sensor
MPG - Miles Per Gallon (Display Panel)
EGR - Exhaust Gas Recirculation
MD - Modulated Displacement
MDA - Modulated Displacement Amplifier
The dash-mounted "CHECK ENGINE" light is used
to inform the technician of detected system malfunctions or
abnormalizes. These malfunctions may be related to the
various operating sensors or to the ECM itself. The light
goes out automatically if the fault clears (intermittent).
However, the ECM stores the trouble code associated with
.the detected failure until the diagnostic system is "Cleared"
or until 20 ignition switch (on-oiT) cycles have occurred
without the fault reappearing.
Proper operation of the light is as fellows:
a. The light is normally off.
b. A bulb check is performed when the ignition is in
the "On" and "Crank" positions. When the engine starts,
the bulb goes out.
c. The light comes on and stays on when a constant
malfunction is detected.
d. If a malfunction is-intermittent, the light will go out
when the malfunction is not present. The light will come on
each time a malfunction is detected (may flicker).
e. The light stays on when the system is displaying the
. diagnostic routine.
The dash mounted digital display panel, normally used
for the ECC system, can be temporarily directed to display
trouble codes stored in the ECM.
HOW TO "ENTER" DIAGNOSTIC MODE
To enter diagnostic mode, proceed as follows:
1. Turn the ignition "ON".
2. Depress the "OEF" and "WARMER" buttons on
the ECC panel simultaneously and hold until ".." appears,
Figure 8D-2. "88" will then be displayed which indicates
the beginning of the diagnostic readout.
3. Trouble codes will be displayed on tl-e digital ECC
panel beginning with the lowest numbered code. Note that
the Ml'G panel goes blank when the system is displaying
in the diagnostic mode.
CODE
1981 DIAGNOSTIC CODES
THE FOLLOWING CODES ARE PROGRAMMED
INTO THE ECM.
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
30
31
32
33
34
35
36
37
33
44
45
51
60
61
62
63
64
65
66
68
70
71
72
73
74
75
76
77
78
79
80
88
90
95
96
97
00
CIRCUIT AFFECTED
NO TACH SIGNAL
O2 SENSOR NOT READY
SHORTED COOLANT SENSOR
OPEN COOLANT SENSOR CIRCUIT
GENERATOR VOLTAGE OUT OF RANGE
CRANK SIGNAL CIRCUIT HIGH
OPEN CRANK SIGNAL CIRCUIT
FUEL PUMP CIRCUIT HIGH
OPEN FUEL PUMP CIRCUIT
SHORTED THROTTLE POSITION
SENSOR CIRCUIT
OPEN THROTTLE POSITION
SENSOR CIRCUIT
EST/BYPASS CIRCUIT SHORTED OR OPEN
SPEED SENSOR FAILURE
MODULATED DISPLACEMENT FAILURE
SHORTED THROTTLE SWITCH CIRCUIT
OPEN THROTTLE SWITCH CIRCUIT
IDLE SPEED CONTROL CIRCUIT
SHORT MAP SENSOR CIRCUIT
OPEN MAP SENSOR CIRCUIT
MAP/BARO SENSOR CORRELATION
MAP HOSE
SHORTED BARO SENSOR CIRCUIT
OPEN BARO SENSOR CIRCUIT
SHORTED MAT SENSOR CIRCUIT
OPEN MAT SENSOR CIRCUIT
O2 SENSOR LEAN
02 SENSOR RICH
PROM INSERTION FAULTY
DRIVE (ADL) SWITCH CIRCUIT
SET AND RESUME SWITCH CIRCUIT
CAR SPEED EXCEEDS MAXIMUM LIMIT
CAR AND SET SPEED TOLERANCE
EXCEEDED
CAR ACCELERATION EXCEEDS
MAXIMUM LIMIT
COOLANT TEMPERATURE EXCEEDS
MAXIMUM LIMIT
ENGINE RPM EXCEEDS MAXIMUM LIMIT
SET AND RESUME SWITCH CIRCUIT
SYSTEM READY SWITCH TESTS
BRAKE LIGHT SWITCH
ISC THROTTLE SWITCH
DRIVE (ADL) SWITCH
BACK-UP LAMP SWITCH
CRUISE ON/OFF CIRCUIT
SET/COAST CIRCUIT
RESUME/ACCELERATION CIRCUIT
INSTANT/AVERAGE MPG BUTTON
RESET MPG BUTTON
A/C CLUTCH CIRCUIT
DISPLAY CHECK
SYSTEM READY TO DISPLAY
ENGINE DATA
SYSTEM READY FOR ACTUATOR CYCLING
ACTUATOR CYCLING
MD CYLINDER SOLENOID CYCLING
ALL DIAGNOSTIC COMPLETE
Fi.jiiro 80-1 DFI Diagnostic Codes
-------
HOW TO "CLEAR" TROUBLE CODES
Trouble codes stored in the ECM's memory may be
cleared (erased) by entering the diagnostic mode and then
depressing the "OFF" and "HI" buttons simultaneously,
Figure 8D-2. Hold until "00" appears. After "00" is
displayed, the ECM will display "70". .
HOW TO "EXIT" DIAGNOSTIC MODE
To get out of the diagnostic mode, depress any of the
ECC "Function" keys (Auto, Econ, etc. except Rear Defog)
or turn ignition switch off for 10 seconds. Trouble codes are
not erased when this is done. The temperature setting will
reappear in the display panel.
DIAGNOSIS PROCEDURE
When the check engine light turns on, it indicates that
a malfunction has occurred for which a trouble code has
been stored. The trouble code can he displayed on the FCC
control panel. The malfunction may or may not result in
abnormal engine operation.
To determine which system(s) has malfunctioned,
proceed as follows:
1. Turn the ignition switch "ON" for 5 seconds.
2. Depress the "OFF" and "WARMER" buttons on
the Electronic Climate Control panel simultaneously and
hole! until ".." appears.
3. The numerals "SS" should then appear, see Figure
8D-3. The purpose of the "S3" display is to check that all
segr,v:::is of I he display are working. Diagnosis should not
be p.ttcmpied unless the entire "88" appears as this could
lead to misdiagnosis (Code 31 could be Code 34 with two
segments of the display inoperative, etc.).
4. If trouble codes are present, they will be displayed
on the digital I.ICC panel as follows:
a. The lowest numbere-.! code will be displayed for
approximately two seconds.
b. Progressively higher numbered code*, i!"present, v.'iil
be displayed consecutively for two second intervals until the
highest code present has been displayed.
c. "88" is again displayed.
d. Parts A, B, and C above will be repeated a second
lime.
c. When the trouble codes have been displayed, code
70 will then be displayed. Code 70 indicates that the ECM
is ready for the next diagnostic feature to be selected.
5. If no trouble codes are present, "88" will be displayed
for a longer period of time, and then the ECM will display
code 70. Code 70 indicates that the ECM is ready for the
next diagnostic feature to be selected.
INTERMITTENT CODES VERSUS HARD
FAILURES
The check engine light will go out automatically if the
malfunction clears. However, the ECM stores the trouble
code associated with the detected failure until the diagnostic
system is cleared or until 20 ignition cycles have occurred
without any fault reappearing. This condition is known as
an intermittent failure.
Therefore, the ECM may have two types of trouble
codes stored in its memory. These two code types are:
A. A code for a malfunction which is a hard failure.
A hard failure turns on t.he check engine light and keeps it
on as long as the malfunction is present.
B. A code for an intermittent malfunction which has
occurred within the last 20 ignition cycles. An intermittent
f.iilure turns off the check engine light when ihe malfur.clion
clears up.
Diagnostic Charts Cannot be Used to Dicrjnose
Intermittent Failures
Intermittent codes should be diagnosed by inspecting
the connectors involved with the affected circuits. However,
if an a flee led circuit is one that may be checked by the
switch tests, output cycling tests, or engine data displays,
make the check on the appropriate circuit.
. .. . .
'-ij''^- ' .'
PRESS TO i^i--_;;.:,-
TROUBLE tfjiJi.. :;.: -;-
CQDES '
. .- *, "'!"' ' -. ."'!'. :'-''' ,. .' '- . '': {"*!&*&*.**''; ..-":'.! j-
-'" V'-:: '};-.' :, '-. --'""_'. .'...-'- f- "- !''' ...- >'!:.
iTuVvKWi'tii'T^' !;r'^B "':'-:^;i5';, K"
.^VJ1.'';.?-'.^ .r>,ji..M.)l!,^. -r:-:-.^;-J.:-' . ;-;: .>Vf--;-."'-".'. "Hf /li;-|^^:'' " I'!
- «':: - --. ' -^ ~-,.>,-~--:,..^-jj *.; __ // iil
PRESS TO
-v :-, 'r:;|:f^ CLEAR
;c!a;: TROUBLE'
i CODES
Figure 8D-?. ECC Control Head
-------
CADILLAC 1981
DFI DIAGNOSTICS
r
VENTER INTO
DIAGNOSTICS
d
CO
O
CO
O
-n '
0
ENTER DIAGNOSTICS BY SIMULTANEOUSLY PUSHING OFF
AND WARMER BUTTONS
» EXIT DIAGNOSTIC MODE BY PUSHING ANY CL!MA7L:
CONTROL BUTTON EXCEPT REAR DEFOG
« CLEAR TROUBLE CODES. AND RETURN TO 70 BY
SIMULTANEOUSLY PUSHING OFF AND HI BUTTONS ON
CLIMATE CONTROL
RESET FROM 90. 95, 96. OR 97 AND RETURN TO 70 BY
SIMULTANEOUSLY PUSHING OFF AND HI BUTTONS ON ECC
CLIMATE CONTROL-
DEPRESS INSTVAVG BUTTON
THROTTLE SW, + ENG. OFF
*r»r AFTER START
ACTUATOR
CYCLING
DEPRESS BRAKE
*
"HROTTLE SVV. + ENG. RUNNING
1 WIN. AUTO
TIME OUT
3 SFC
- /-/-/
/ /
CYLINDER
SELECT
8
G
4
CYL. IN.ST./AVG.
CYL. RESET
CYL. ACTIVE CYL.
CRUISE SWITCH ON/OFF
ENGINE
DATA
INST./AVG. TO INCR.
-------
ELECTRONIC DIAGNOSIS^COMPUTER CONTROLLED 8D-5
During any diagnostic interrogation,'it is necessary to
determine if the diagnostic code or codes are hard failures
or intermittent failures. To make this determination,
proceed as follows:
1. Enter diagnostics and note stored trouble codes.
2. If one code exists and the "Check Engine" light is
on (engine running) follow the appropriate trouble tree. If
"Check Engine" light is off (engine running), clear trouble
codes. If more than one code exists, clear trouble codes.
3. Exit diagnostics by turning the ignition switch off for
10 seconds.
4. Turn the ignition on, wait 5 seconds, and then start
the engine.
5. Accelerate the engine to approximately 2000 RPM
for a few seconds.
6. Return the engine to idle speeds.
7. Shift the transmission into drive.
8. Shift the transmission back into park.
9. If the "check engine" light comes on, enter
diagnostics, read, and record the trouble codes. This will
reveal only "hard failures" codes. The Cruise Control codes
60 through 68 never set a check engine light; therefore, treat
them as hard failures. Codes 13, 44, 45, 24 and 25 may
require a road test to reset a "hard failure" after the trouble
codes have been cleared.
If the light does not come on, then all stored codes are
intermittent failures except for codes 13, 33, 44, and 45. If
the intermit lent code is a code 33, a special procedure must
be followed. Refer to diagnostic chart 33A, "Intermittent
MAP/BAKO Correlation Test". If the intermittent code.is
code 13, 44, or 45, use the diagnostic chart for code 13, 44,
or 45 Ixv.-'.use these panicular charts have been designed to
account for intermittent*.
If the vehicle exhibits performance problems and has
no codes set, refer to the performance diagnosis charts. A
component which is cheeked by the trouble codes will rarely
cause a performance problem when no trouble codes are set.
10. fierjii the diagnosis with the lowest code number
which is displayed. Ifcod.es 51 or 16 are present, begin the
diagnosis with code 51 and then proceed to code 16.
CODE 70
Code 70 is a decision point. When code 70 is displayed,
the technician should select ihe diagnostic feature that he
wants to display. The following choices are available:
A. Switch tests
B. Engine data display
C. Output cycling tests
D. Exit diagnostics or clear codes and exit diagnostics.
SWITCH TESTS PROCEDURE
Code 70 must be displayed on the Electronic Climate
Control panel before the switch tests can begin. To perform
the switch tests, proceed as follows:
1. Depress and release the brake pedal; the switch tests
begin as the display switches from code 70 to code 71,.see
Figure KD-3. (If the display doesn't advnr.ce to code 71,
refer to ihe diagnosis chart, code 71, because the ECM. is
not processing the brake signal.)
2. With code 71 displayed, depress and release the brake
pedal af.ain to lest the Cruise Control brake circuit, see
Figure oD-4. When this check is complete, tlio display will
automatically sequence to code 72. If this check is not
performed within 10 seconds, the display will auiomaticaHv
sequence to code 72.but code 71 will be stored in the ECM's
memory as a failure.
3. With code 72 displayed, depress the throtik- from
the idle position to the wide open throttle position and then
release the throttle. While .this action is being performed.
the ECM checks the throttle switch for proper operation.
When this check is complete, the display will automatically
sequence to code 73. If this check is not performed within
10 seconds, the display will automatically sequence to code
73 but code 72 will be stored in the ECM's memory as a
failure.
4. With code 73 displayed, shift the transmission lever
into drive and then neutral. This action checks the operation
of the drive switch. When this check has been completed.
(lie display will automatically sequence to code 74. If tins
check is not performed formed within 10 seconds, code 73
will be stored in the ECM's memory as a failure.
5. With code 74 displayed, shift the transmission lever
to reverse and then to park. This action checks the operation
of the reverse switch. If the transmission is not shifted within
10 seconds, a code 74 will be stored as a failure. When the
check is completed, the panel will automatically .sequence
to code 75.
On cars without Cruise Control, codes 75, 76 and
77will be displayed during this switch test. When these
codes are displayed during the switch test, allow the
code to reach its 10 second time out. After tin's time out
has elapsed, the display will advance to the next code.
Allow codes 75, 76 and 77 to time out t series within the 10 seconds time out to us-
s 1.1 re test accuracy.
6. With code 75 displayed, switch the Cruise Control
instrument panel switch from off to on and
to off.
When this check is complete, the display will automatically
sequence to code 76. If this check is not performed within
10 seconds, the display will automatically sequence to code
76 but code 75 will be stored in the ECM's memory as a
failure.
7. With code 76 displayed and with the cruise
instrument panel switch in the on position, depress and
release the set/coast but ton to verify the operation of this
switch. When this check is complete, the display will
automatically sequence to code 77. If this check is not
completed within 10 seconds, the ECM will store code 76
as a failure.
8. With code 77 displayed and with the cruise
instrument panel switch in the on position, depress and
release llie resume/ acceleration switch to ch-.-ek the
operation of this switch. If this check is not completed
within 10 seconds, the ECM will store code 77 as a failure.
The display will advance to code 78.
9. With code 7S displayed, depress and release the
"average" button on tlic MPG panel. When this check is
complete, the display will automatically cycle to code 79.
This must be completed within 10 seconds or a code 7S will
be set as a failure.
10. With code 79 displayed, depress and release the
"reset" button on the MPG pane! within 10 seconds to test
the operation of this switch. The panel will aui.'maiically
cvcle to code SO.
-------
GD-6 ELECTRONIC DIAGNOSIS - COMPUTER CONTROLLED
11. With code SO displayed, depress and release the rear
defogger button on the ECC panel. This action checks the
ECM's ability to recognize and process the air conditioning
clutch signal. Ho\ve\cr, the compressor cycling switch
leading to the compressor drive circuit of the ECC power
module must be closed in order to energize the A/C
compressor clutch. Sometimes, the engine may need to be
running and the ECC may need to be operating in auto and
60 to close the contacts of the compressor cycling switch.
This procedure must be completed within 10 seconds to
avoid setting code SO as a failure. This is the. end of the
switch tests.
On cars without rear defogger, code 80 will be
displayed during the switch test. When code 80 is displayed,
momentarily supply 12 volts to the blue wire in the six wire
weather pack connector on the ECC power module (engine
compartment) to pass code SO.
12. When the switch tests are completed, the ECM will
now go back and display the switch codes which did not test
properly. Each code which did not pass will be displayed
beginning with the lowest number. The codes will not
disappear until the affected switch circuit has either been
repaired or retestecl. Refer to the appropriate diagnosis chart
for each trouble code.
13. After the switch tesis are completed and all circuits
pass, the ECC panel d; SWITCH TEST CODES:
70 SYSTEM READY
71 CRUISE CONTROL BRAKE SWITCH
72 ISC THROTTLE SWITCH
73 DRIVE (ADL) SWITCH
74 BACKUP LAMP SWITCH
*75 CRUISE OFF/ON
*76 CRUISE SET/COAST
*77 CRUISE RESUM/ACCEL.
78 AVG. MPG SWITCH
79 RESET MPG SWITCH
*80 A/C CLUTCH (PRESS REAR DEFOG SWITCH)
-A-NEW FOR 1981
_J
Fiyure 80-4 Switch Test Series
-------
- 1981 DIAGNOSTIC ROUTINE
ENGINE DATA SERIES
VARIOUS ENGINE SENSOR AND ENGINE CONTROL VALUES CAN BE
DISPLAYED AT THE TECHNICIAN'S OPTION
I
n n
lU
ENGINE
DATA
i
ENGINE DATA DISPLAY
PARAMETER
. NO.
01
.02
. 03
04
05
06
07
08
09
10
11
PARAMETER
IPS- (THROTTLE ANGLE)
MAP
BARO
COOLANT
MAT
INJECTOR PULSE
WIDTH
O2 SENSOR
SPARK ADVANCE
IGNITION CYCLES
OPEN/CLOSED-LOOP
INDICATOR
BATTERY VOLTAGE
VALUE
XX
XX
XX
XX
XX
X.X
.XX
XX
XX
X
X.X
1
1
UNITS
DEGREES
kPa
kPa
0 = -40:C 99 =-- 150°C
0 = -40CC 99 = 150°C
MSEC
VOLTS
DEGREES
KEY CYCLES
0 = OPEN LOOP
1 = CLOSED LOOP
VOLTS WILL NOT
DISPLAY
10'S DIGIT
Figuro 8D-5 Engine Data Display
01 The throttle angle is displayed in degrees.
02 The MAP value is displayed as a number between
1 p.ncl 99. A pressure reading of 100 and 101 is displayed
as a 99 because it is not possible to display more than 2 digits
on the ECC panel.
03 The BARO value is displayed in the same manner
as the MAP value.
04 The coolant temperature is a sealed number which
reads between 0 and 99. The value of 0 corresponds to -40°C,
and the value of 99 corresponds to 150"C, sec Figure SD-6
for additional conversion values.
05 The manifold air temperature value is displayed in
the same manner as the coolant temperature.
06 The injector pulse width is displayed in milliseconds.
A decimal point will not appear but it has to be assumed
between the two digits, (i.e. - 32 means 3.2 milliseconds)
07 The oxygen sensor voltage is displayed in volts and
the decimal point lias to be assumed before the two digit's.
(i.e. - 60 means .60 volts)
OS The spark advance value is displayed in degrees.
09 The ignition cycle value is the number of times that
the ig!iiii;>r. has been cycled since the trouble code was --ct.
10 The open closed loop indicator tells the tec':ini;:an
whether the F.CM is operating the system in closed l.:op
operation or in open loop opera'.ion. A value of 1 indicuies
closed loop operation; a value of 0 indicates open loop
operation.
11 The battery voltage is read in volts; however, the iO's
digit will not display and a decimal point has to be assumed
between the two numbers (23 should be read as 12.3 \o';s).
When the engine data display is initiated, the ECC v-i!l
display 01 for one second to indicate the first parair.eier
check and then a two digit number will be displayed for five
seconds to indicate the first parameter value. A single digit
parameter value will be displayed as a "blank X". The ECC
will continue to repeal his sequence of events until ;!ie
technician decides to move to the next parameter, see Figure
8D-5.
-------
OUTPUT CYCLING TESTS PROCEDURE
T.his series of tests can be initiated after 95 is displayed
on the ECC panel. The display of 95 can be reached by the
following methods:
1. Depress the instant/average button while code 70 is
displayed on the ECC panel, see Figure 8D-3. If the display
doesn't adv.mce to code 95, refer to code 78 of the switch
tests..
2. Depress the instant/average button while parameter
iill of the engine data display series is being displayed.
The output cycling tests consist of two separate
operations:
A. With the engine running, the cylinder select test,
code 97, operates the modulated displacement solenoids.
B. With the engine off, the actuator cycling test, code
96, turns the ECM's outputs on and off.
To enter the actuator cycling tests, proceed as follows:
A. The engine must be running.
B. Turn the engine off and within 2 seconds, turn the
ignition on.
C. Enter diagnostics and display code 95. See Figure
8D-7.
D. Depress the accelerator pedal to the wide open
throttle position (throttle switch open) and release it
(throttle switch closed). Code 96 will appear on the display.
E. Turn the cruise instrument panel switch to the on
position so that the Cruise Con.trol outputs will cycle.
P. The actuator cycling test will end automatically after
1 minute-; of cycling and the display will switch from code
96 to code 95.
The group A outputs will cycle on and off for 3 seconds .
and then the group B outputs will cycle on and off for 3
seconds. The Cruise Control power valve operates
continuously. Group A will continue to alternate with
Group B until the 2 minute automatic shut off occurs.
To enter the cylinder select tests, proceed as follows:
A. The engine must be running.
B. Enter diagnostic-; and display code 95, sec Figure
8D-7.
C. Depress the accelerator pedal to the wide open
throttle position (throttle switch open) and release it
(throttle switch closed). Code 97 will appear on the display.
D. With no button of the MI'G panel depressed, the
ECM will continue to control the cylinders automatically.
E. Depressing the instant/average button of the MI'G
panel \\ill force the engine to operate in 8 cylinder mode as
long as the button is depressed.
COOLANT
TEMPERATURE CONVERSION
CODE
0
8
12
16
21
25
30
35
40
45
50
52
54
56
58
60
62
64
66
68
70
72
73
75
80
85
90
99
°F
-40
-12
-f 1
15
32
46
64
81
98
115
133
140
147
153
160
167
174
181
188
195
202
209
212
219
236
254
271
302
CC
-40
-25
-17
_ g
-f 0
8
18
27
37
46
56
60
64
67
71
75
79
83
87
90
94
98
100
104
113
123
133
150
Figure 8D-6 Temperature Conversion Table
F. Depressing the reset button of the MPG panel will
force the engine to operate in 6 cylinder mode until the
button is released.
G. Depressing the active cylinder button of the MPG
panel will force the engine to operate in 4 cylinder mode
until the button is released.
The switch tests, the engine data displays, and the
output cycling tests can be used to isolate intermittent
failures.
-------
o TH1STE
USING
1S81
OU1
EST SERIES ENABLES TECHNIC
ECM COMMAND SIGNALS
THROTTLE SWITCH
AND ENGINE OFF
L/u
ACTUATOR
CYCLING
DIAGNOSTIC ROU
FPUT CYCLING SEfl
IAN TO ACTIVATE \
or
1 ! ~'
\ OUTPUT
J CYCLING
TINE
IES
/ARIOUS ENGINE CONTROL SO
I THROTTLE SWITCH A
j ENGINE RUNNING
I q~j
$ it-
\ CYLINDER
\ SELECT
i
LENOIDS
!
i
i
i
'
SJD
!
i
ci
i
i .
i
3 SEC.
ALLOWS MANUAL SELECTION OF
8. 6 OR 4 CYLINDER OPERATION
IN ADDITION TO NORMAL
AUTOMATIC MODE
8 CYL. INST/AVG.
6 CYL. RESET
4 CYL. ACTIVE CYL.
AUTOMATIC NO BUTTONS
COOLANT LIGHT
CRUISE POWER VALVE
CRUISE VACUUM VALVE
AIR SWITCHING VALVE
ISC EXTEND
CRUISE ON/OFF SWITCH
CANISTER PURGE SOLENOID
EGR VALVE SOLENOID
AIR DIVERT VALVE
ISC RETRACT
Figure 8D-7 Output Cycling Tests
yv~^i;^
-------
Jj.
ATTACHMENT 4
Test Vehicle Description
Model/Year
Make
Emission Control System
Engine Configuration
Bore x Stroke
Displacement
Rated Horsepower
Transmission
Chassis Type
Tire Size
Inertial Weight
Vin
AHP
Engine Family
Fuel Type
Compression Ratio
Differential
1981
Cadillac Seville
EGR, air injection, closed loop TBI, dual bed
catalytic converter
V-8 modulated displacement
3.8 inches x A.06 inches
368.0 cubic inches
140
A-3
Sedan
P 205/75 R 15
4250 Ibs.
1G6AS6991BE692250
10.0
16T5ADB
Unleaded - IND HO
8.2:1
4MG
-------
Attachment 5
Dilute Sample Testing
Date
Feb 81
Feb 81
Feb 81
Feb 81
Feb 81
Feb 81
Feb 81
Feb 81
. Feb 81
Feb 81
Mar 81
Test Numbers
80-7654-55
80-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
80-7673-74
80-7675-76
80-7677-7917
H£
.299
.292
.491
.867
.310
.765
14.797
7.410
.279
1.283
.267
C£
3.01
2.69
10.39
27.62
4.12
1.72
204.92
256.91
2.14
19.64
1.19
FTP
CO?
621.
623.
604.
610.
910.
642.
557.
688.
807.
589.
601.
NOx
0.71
0.76
0.71
0.39
3.94
2.82
0.24
0.11
3.90
0.38
0.86
15.
14.2
14.1
14.3
13.5
9.7
13.7
9.6
7.9
10.9
14.0
14.7
H£
.063
.078
.244
.159
.082
.036
3.524
3.075
.054
.461
.062
CO
0.73
1.63
7.65
4.29
2.75
0.05
56.87
102.36
1.16
15.14
0.33
HFET
CO?
399.
421.
408.
383.
435.
462.
492.
394.
417.
390.
398.
NOx
0.83
0.79
0.91
1.10
0.56
2.24
0.14
0.03
1.16
0.48
0.98
FE
22.2
.2Q.9
21.1
22.7
20.2
19.2
15.0
15.7
21.2
21.4
22.2
ComrtientB
Baseline
Baseline
ECO Disconnected
ECO Shorted
TPS Disconnected
CIS Disconnected
MAP Disconnected
PROM 'Errors
TPS Shorted
MAT Disconnected
Baseline
U)
ro
-------
Attachment 6
I/M Testing Before Catalyst
Four Mode Idle
Two Mode Loaded
Date
4 Feb 81
6 Feb 81
11 Feb 81
12 Feb 81
13 Feb 81
19 Feb 81
20 Feb 81
24 Feb 81
26 Feb 81
27 Feb 81
3 Mar 81
Test Numbers
80-7654-55
80-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
80-7673-74
80-7675-76
80-7677-7917
50 Cruise
HC/CO
125/.5
75/.3S
100/.14
200/2.5
80/.4
60/.13
140/2.0
160/7.2
90/.37
120/.45
115/.43
Idle
HC/CO
400/.8
300/.7
325/1.2
250/.3
250/.75
150/.12
900/10+
100/3.8
25/.4S
400/.5
300 /. 7
2500
HC/CO
95/.6S
70/.55
ISO/. 4
ISO/. 35
45/.S
40/.18
650/10+
70/2.2
30/.40
70/.45
100/.6
Idle
HC/CO
400/.85
250/.8
400/.5
400/.9
300/.8
ISO/. 15
1100/10+
100/3.5
30/.45
- 400/.5
280/.85
Drive
HC/CO
275/.90
27S/.8
200/.2
250/.2
250/1.0
100/.10
550/9.5
280/10
135/.75
200/.5
280/.85
30 MPH
HC/CO
120/.6
200/1.0
160/.9
rso/.4
ISO/. 9
75/.10
165/5.0
200/8.0
90/.45
115/.5
100/.5
Idle
HC/CO
100/.8
400/.7
47S/.5
600/.5
275/1.2
175/.12
250/10+
70/1.4
30/.35
200/.5 .
300/.55
Comments
Base line
Baseline
EGO Disconnected
ECO Shorted
TPS Disconnecter
CTS Disconnecter
MAP Disconnecte.
PROM Errors.
TPS Shorted
MAT Disconnecter
Base 1ine
NOTE: Before catalyst idle emissions fluctuated considerably in most tests.
The values recorded represent the mean value of the emissions based on
observation of the analog meter on the analyzer.
-------
I/M Testing After Catalyst
Four Mode Idle
Two Modn Londed
Date
4 Fcb 81
6 Fob 81
11 Feb 81
12 Feb 81
13 Feb 81
19 Feb 81
20 Feb 81
24 Feb 81
26 Feb 81
27 Feb 81
3 Mar 81
Test Numbers
80-7654-55
8.0-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
80-7673-74
80-7675-76
80-7677-7917
50 Cruise
HC/CO
45/.03
60/.10
35/.05
25/.01
25/.03
30/.03
110/2.0
150/6.4
25/.03
10/.02
3S/.22
Idle
HC/CO
40/.03
60/.03
135/.1
40/.01
40/.04
25/.03
800/10+
100/3.5
15/.03
40/.03
25/.02
2500
HC/CO
35/.03
45/.03
40/.03
35/.01
30/.04
20/.03
580/10+
50/1.9
20/.04
25/.03
35/.02
Idle
H'C/CO
40/.03
SO/. 03
50/.04
35/.01
25/.04
25/.03
1000/10+
100/3.8
20/.03
50/.03
25/.02
Drive
HC/CO
30/.03
40/.03
40/.04
35/.01
30/.04
25/.03
500/9.0
260/9.8
20/.03
35/.03
35/.02
30 MPH
HC/CO
20/.03
70/.03
60/.7
40/.01
30/.04
25/.03
150/4.8
190/8.0
25/.04
35/.03
25/.02
Idle
HC/CO
10/.03
45/.03
20/.03
35/.01
50/.03
20/.02
220/10
70/1.1
25/.03
25/.03
20/.02
Coraacnta
Baseline
Rase 1i ne
ECO Disconnected
ECO Shorted
TPS Disconnected
CIS Disconnected
MAP Disconnected
PROM Errors
TPS Shorted
MAT Disconnected
Baseline
-------
Date
Teat Numbers
4 Fob 81
6 Fob 81
11 Feb 81
12 Feb 81
13 Feb 81
19 Keb 81
20 Feb 81
24 Feb 81
26 Feb 81
27 Feb 81
3 Mar 81
80-7654-55
80-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
8O-7673-74
80-7675-76
80-7677-7917
RPM
580
600
600
600
500
775
600
1700
2170
600
600
Attachment 7
Results of Propane Injection Diagnostic Procedure
4CFH Propane Neutral
ICO
.03
.03
.02
.02
.03
.03
10+
1.7
.02
.03
.02
CODE
a
a
a
a,c
b
a
e
e
e
a
a
RPM
635
640
645
625
470
840
630
640
RPM
600
600
625
620
490
775
600
1700
2170
600
610
ICO
.03
.03
2.5
1.7
.03
.03
10+
2.8
.02
.03
.02
CODE RPM RPH ICO CommentB
b 570 600 .03 Baseline
b 560 595 .03 Baseline
b 590 600 .02 ECO Disconnected
b 590 600 .02 ECO Shorted
a.c 550 500 .03 TPS Disconnected
a 860 760 .03 CIS Disconnected
a 620 600 10+ MAP Disconnected
e 1700 1.9 PROM Errors
e 2170 .02 TPS Shorted
b 540 600 .03 MAT Disconnected
b 560 600 .02 Baseline
-------
ATTACHMENT 7, continued
4CFH Propane Drive
Date
Test Numbers
RPM
ICO
CODE
CODE
RPM
RPM
ICO
4 Feb 81
6 Feb 81
11 Feb 81
12 Feb 81
13 Feb 81
19 Feb 81
20 Feb 81
24 Feb 81
26 Fe.b 81
27 Feb 81
3 Mar 81
80-7654-55
80-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
80-7673-74
80-7675-76
80-7677-7917
490
495
500
500
490
645
500
900
1160
490
495
.03
.04
.01
.02
.03
.03
9.8
9.0
.02
.03
.02
a
b
e
a
a
a
b
e
e
a
a
510
470
510
500
650
490
500
510
495
490
500
498
490
640
490
900
1160
500 '
500
.03
.03
1.7
1.5
.03
.03
10 +
10 +
.02
.03
.02
b
a
b
b
b
b
a
e
e
b
b
470
510
490
490
480
620
510
460
560
495
500
500
500
495
640
500
900
1160
500
600
.03
.03
.0!
.02
.03
.03
9.4
9.2
.02
.03
.02
Comment 8
Baneline
Base 1ine
ECO Disconnected
ECO Shorted
TPS Disconnected
CIS Disconnected
MAP Disconnected
PROM Errors
TPS Shorted
MAT Disconnected
Base 1inc
-------
Attachment 8
Roeults of On-Board Diagnostic Check
Dace
A Fob 81
6 Feb 81
11 Feb 81
12 Feb 81
13 Feb 81
19 Feb 81
20-Feb 81
24 Fob 81
26 Feb 81
27 Kc-b 81
3 Mar 81
Test Numbers
80-7654-55
80-7656-57
80-7658-59
80-7661-62
80-7663-64
80-7665-66
80-7667-68
80-7669-70
80-7673-74
80-7675-76
80-7677-7917
Trouble Code. Output
88
88
88,13
88,44
88.22,30
88,15
8.8,32
88,21,30
88,38
88
Trouble Code Identification
88 System operational verification
13 " ECO sensor not ready
44 » ECO censor lean
22 Open IPS circuit
30 " Idle speed control circuit
15 " Open CTS fienoor circuit
32 Open map sensor circuit
.. " Diagnoseics inoperative
21 Shorted IPS circuit
33 Open cot ocnoor circuit
Closed Loop
Yes
Yes
No
NO
Yes
No
Yes
?
Yea
Ye 8
No
Comments
Baseline
Baseline
ECO Disconnected
RCO Shorted
IPS Disconnected
CTS Disconnected
HAT Disconnected
PROM Errors
TI'S Shorted
HAT Disconnected
Baselinc
U)
------- |