PONTIAC FIERO 1988 Service Repair Manual

6E2-C7-2 DRlVEABlLlTV AND EMISSIONS - 5.OL
EGR VALVE AIR BLEED
EXHAUST GAS HOLE
1 INTAKE
AIR SMALL SPRING
1 VACUUM PORT LARGE SPRING
DIAPHRAGM
45 01 13-61
Figure C7-2 - Negative Backpressure EGR Valve
EGR VALVE IDENTIFICATION
@ Negative backpressure EGR valves will have an
"N" stamped on the top side of the valve after the
part number (Figure
C7-3).
@ Positive backpressure EGR valves will have a "P"
stamped on the top side of the valve, after the part
number.
@ Port EGR valves have no identification stamped
after the part number.
When replacing an EGR valve, always check for
correct part number in the parts catalog or
supplemental bulletin.
RESULTS OF INCORRECT OPERATION
Too much EGR flow (at idle, cruise, or cold
operation) and may result in any of the following
conditions:
- Engine stops after cold start.
- Engine stops at idle after deceleration.
- Car surges during cruise.
- Rough idle.
Too little or no EGR flow allows combustion
temperatures to get too high during acceleration and
load conditions. This could causes:
- Spark knock (detonation).
- Engine overheating.
- Emission test failure.
Figure C7-3 - EGR Valve Identification
DIAGNOSIS
Diagnosis of the ECM controlled EGR system on
the
5.OL is covered in CHART C-7 at the end of this
section. If the vehicle has
a stored Code 32 see that
chart first.
ON-CAR SERVICE
ECR VALVE
Remove or Disconnect
1. Air cleaner.
2. EGR valve vacuum hose at valve.
3. Bolts.
4. EGR valve from manifold.
EGR Manifold Passage
inspect
If EGR passages in the inlet manifold indicate
excessive build-up of deposits, the passages should be
cleaned. Care should be taken to ensure that all loose
particles are completely removed to prevent them
from clogging the EGR valve or from being ingested
into the engine.
Clean
1. With a wire wheel, buff the exhaust deposits from
the mounting surface and around the valve.
2. Look for exhaust deposits in the valve outlet.
Remove deposit build-up with a screwdriver.
3. Clean mounting surfaces of intake manifold and
valve assembly.

DRIVEABILITY AND EMISSIONS - 5.OL (VIN E) 6EZ-C7-3
EGR CONTROL SOLENOID
Install or Connect
1, EGR valve on intake manifold using new gasket.
2. Bolts and tighten to 22 N . m (16 lb. ft.).
3. Vacuum hose to valve.
4. Air cleaner.
EGR VALVE
GASKET
13] BOLT (2) 85 4417-6
Figure C7-4 - EGR to Manifold Mounting 5.OL
( EGR SOLENOID ( BOLT 14-20 Narn (10-14 FT. LBS.)
Remove or Disconnect
1. Negative battery cable.
2. Air cleaner.
3. Electrical connector at solenoid,
(Figure
C7-4)
4. Vacuum hoses.
5. Nut and solenoid.
a lnstall or Connect
1. Solenoid and bracket. Tighten nut to 24 N . m
(17 lb. ft.).
2. Vacuum hoses.
3. Electrical connector.
4. Air cleaner.
5. Negative battery cable.
PARTS INFORMATION
PART NAME GROUP
...................... Valve, EGR 3.670
.......... Solenoid, EGR Cont Vlv Rly 3.670
................. Gasket, EGR Valve 3.680
Figure C7-5 - EGR Control Solenoid 5.OL

6E2-C7-4 DRIVEABILITY AND EMISSIONS - 5.OL (VIN E)
TO EGR VALVE
EGR SOLENOID
CHART C-7
EXHAUST GAS RECIRULATIOM (EGR) CHECK
5.QL (VIN E) "F" "SERIES (TBI)
Circuit Description :
The ECM operates a solenoid to control the exhaust gas recirculation (EGR) valve. This
solenoid is
normally closed. By providing a ground path, the ECN energizes the solenoid which then allows vacuum to pass
to the EGR valve. The
ECM control of the EGR is based on the following inputs:
@ Engine coolant temperature - above 25°C.
@ TPS - off idle
@ MAP
If Code 24 is stored, use that chart first.
Test Description: Numbers below refer to circled
numbers on the diagnostic chart.
1. Checks for solenoid stuck open.
2. Checks for solenoid always being energized.
3. Grounding test terminal will energize the solenoid
and vacuum will drop.
4. Negative backpressure valve should hold vacuum
with engine
"OFF".
5. When engine is started, exhaust backpressure
should cause vacuum to bleed off and valve to fully
close.
6. 5.OL engines have a manifold vacuum source
which should have at least
7 hg at idle.

DRIVEABILITY AND EMISSIONS - 5.OL (WIN E) 6E2-C7-5
SHOULD BE AT LEAST (7") HG VACUUM AT 2000 RPM.
SIDE OF EGR SOLENOID.
APPLY VACUUM AND OBSERVE VALVE.
OBSERVE EGR
DIAPHRAGM WHILE
APPLYING VACUUM.
DIAPHRAGM SHOULD
MOVE FREELY AND
HOLD VACUUM FOR AT
LEAST
20 SECONDS.
@ START ENGINE AND IMMEDIATELY
OBSERVE VACUUM GAGE ON
VACUUM PUMP.
@ VALVE IS GOOD IF DIAPHRAGM
HAS MOVED TO SEATED POSITION
(VALVE CLOSED) AND VACUUM
DROPPED WHILE STARTING
M HOSE BETWEEN
EGR VALVE IS OK.
ESTRICTIONS) IF FOUND, THE EGR

6E2-C7-6 DRIVEABILITY AND EMISSIONS - 5.OL (VIN E)
BLANK

DRIVEABILITY AND EMISSIONS - 5.0L (VIM E) 6E2-C8-1
SECTION C8
"FRANSMISSIBN CONVERnEW CLUTCH (TCC) SYSTEM
CONTENTS
GENERAL DESCRIPTION ............... C8-1 RESULTS OF INCORRECT TCC
PURPOSE
........................ C8-1 OPERATION ..................... C8-2
......................... OPERATION ...................... C8-1 DIAGNOSIS CS-2
.................... CIRCUIT DESCRIPTION ....e.e..eea..e C8-1 ON-CAR SERVICE C8-2
................. PARTS INFORMATION C8-2
GENERAL DESCRIPTION
PURPOSE
The transmission converter clutch (TCC) system
is designed to eliminate power loss by the converter
(slippage) thus increasing fuel economy. By locking
the converter clutch,
a more effective coupling to the
flywheel is achieved. The converter clutch is operated
by an ECM controlled solenoid.
OPERATION
Engagement of the TCC is accomplished by a
solenoid operated valve within the transmission. The
solenoid is activated when an internal switch in the
ECM is grounded. Although the ECM may command
the TCC
"ON", the converter clutch will not apply
until internal transmission fluid pressure require-
ments are met. See Section
"7A".
Before the ECM activates the TCC apply solenoid,
several inputs must be monitored:
e Vehicle Speed. Must be above a certain value
before the TCC can be applied.
Coolant Temperature. The engine coolant
temperature must be above a certain value
before the TCC can be applied.
@ Throttle Position Sensor. After the TCC is
applied, during low engine load condition, the
ECM uses the information from the TPS to
release the clutch when the car is accelerating
or decelerating at a certain rate.
CIRCUIT DESCRIPTION
When the brake pedal is not depressed (switch
closed), battery voltage will be fed to the TCC
solenoid. If the ECM has determined that conditions
are correct, the circuit from the TCC solenoid will be
completed to ground through the ECM and the TCC
solenoid will be activated.
Figure C8-1 - TCC Solenoid
Some transmission use other internal switches in
addition to the TCC solenoid.
@ 700-R4. transmissions normally use a 4th gear
switch to send
a signal to the ECM telling it
when the transmission is in
4th gear. The
ECM uses this information to vary the
conditions under which the clutch applies or
releases. However, the transmission does not
have to be in
4th gear in order for the ECM to
turn the clutch
"ON"
The 12 volt power supply for the solenoid in the
transmission is provided through
a normally closed
switch located on the brake pedal linkage. When the
brake pedal is depressed (switch open), the power
supply to the TCC solenoid is interrupted and the TCC
is disengaged regardless of any other conditions.

6Ef-C8-2 BRlVEABlLlYV AND EMISSIONS - 5.OL (VIN E) ----
RESULTS OF INCORRECTTCC OPERATION
An engine stall will result if the converter clutch
remains applied at all times.
If the converter clutch does not apply, fuel
economy may be lower than expected.
The transmission converter clutch
(TCC) system
has different operating characteristics than an
automatic transmission without TCC.
If the driver
complains of a "chuggle" or "surge" condition, the car
should be road tested and compared to a similar car to
see if a real problem exists. Another TCC complaint
may be
a downshift felt when going up a grade,
especially with cruise control. This may not be
a
downshift, but a clutch disengagement due to the
change in TPS to maintain cruising speed. The
Owner's Manual section on TCC operation should be
reviewed with the driver.
DIAGNOSIS
The diagnosis of the TCC system is covered in
ClIART C-8. If the ECM detects a problem in the VSS
system, a Code
24 should set. In this case see Code 24
Chart.
If the ECM doesn't switch the TCC "ON" when
driving, but will turn it
"ON" when the "test"
terminal is grounded with ignition "ON" and engine
stopped, the sensors such as coolant, speed, and
throttle position should be checked.
ON-CAW SERVICE
@ See Section "7" for TCC Solenoid.
@ See Section "SH" for VSS (HP mounted) and brake
system.
PAR- SNFORMATBIQN
PART NAME GRQUQ
.......................... Sensor, VSS 9.761
........................ Solenoid, TCC 4.122

DRIVEABILITY AND EMiSS88NS - 5.0% (VIN E) 6E2-C8-3

6EZ-C8-4 DRIVEABILITY AND EMISSIONS - 5.OL (VIN E)
I5 WAY (FRONT VIEW)
SPEED INPUT
4rH GEAR SIGNAL
422 TANIBLK
ALDL CONNECTOR
CHART C-8A
TRANSMISSION CONVERTER CLUTCH (TCC)
ELECTRICAL DIAGNOSIS
(Page 1 of 2)
5.OL (VIN E) "F" "SERIES (TBI)
Circuit Description:
The purpose of the automatic transmission torque converter clutch is to eliminate the power loss of the
torque converter, when the vehicle is in a cruise condition. This allows the convenience of the automatic
transmission and the fuel economy of a manual transmission.
Fused battery ignition is supplied to the TCC solenoid through the brake switch. the ECM will engage
TCC
by grounding CKT 422 to energize the solenoid.
TCC will engage when:
- Vehicle speed above 24 mph - Engine at normal operating temperature (above 70°C, 156°F)
- Throttle position sensor output not changing, indicating a steady road speed
- Brake switch closed
Test Description: Numbers below refer to circled solenoids
and relays before installing a
numbers on the diagnostic chart. replacement ECM. Replace
any solenoid or relay
1. Confirms 12 volt supply as well as continuity of that
measures less than 20 ohms.
TCC circuit.
2. Grounding the diagnostic terminal with engine Diagnostic Aids:
"OFF", should energize the capability of the ECM An
engine coolant thermostat that is stuck open or
to control the solenoid. opens
at too low a temperature, may result in an
3. Solenoid coil resistance must measure more than inoperative TCC.
20 ohms. Less resistance will cause early failure
of the ECM
drive^.". Using an ohmmeter, check
the solenoid coil resistance of
all ECM controlled

DRIVEABILITY AND EMISSIONS - 5.8L (VIN E) 6EZ-C8-5
TRANSMlSSlON CONVERTER CLUTCI-I (KC)
@ GROUND DIAGNOSTIC 22 SHORTED TO
I EQUIPPED WITH I I THE CORRECT o WITH TEST LIGHT I PROM. TO CHECK I CONNECTED I 4TCI GEAR SWITCH I I (700-R4ONLY),SEE I CHART C-8 (2 OF 2). 1 L ------------ A