1988 PONTIAC FIERO battery replacement

6E3-Cl-4 2.8L (VIN S) DRIVEABILITY AND EMISSIONS
BarWNeutral Switch (Auto Only)
The ParWNeutral (PIN) switch indicates to the
ECM when the transmission is in Park or Neutral.
This information is used for the TCC and the IAC
valve operation.
Important
Vehicle should not be driven with ParWNeutral
switch disconnected as idle quality will be affected
and a possible false Code
24 (VSS).
See Section "$A" for more information on the PIN
switch, which is part of the neutrallstart and backup
light switch assembly.
NC '"n" Signal
This signal tells the ECM that the A/C selector
Switch is turned on, and that the pressure cycling
switch is closed. The ECM uses this to adjust the idle
Speed when the air conditioning is working.
If this signal is not available to the ECM, idle may
be rough, especially when the
A/C compressor cycles.
The voltage at ECM terminal "B8" should equal
battery voltage when
AIC is requested and the
pressure cycling switch is closed.
The signal at
B8 will cause the ECM to turn on the
A/C clutch by energizing the A/C relay.
Distributor Reference Signal
The distributor sends a signal to the ECM to tell it
both engine RPM and crankshaft position. See EST
System for further information.
To read the codes, use a "Scan" tool or ground the
diagnostic terminal with the engine not running and
the ignition on. The "Service Engine Soon" light will
flash Code 12 three times and
then flash each code
stored in memory three times. All codes stored in
memory would have been read when Code 12 was
flashed again. No new codes can be stored when in the
Diagnostics Mode (diagnostics lead grounded).
This
eliminates confusion while the system is being worked
on. To clear the codes from memory:
@ Ignition off
@ Remove fuse located in a weather proof holder
located near the battery for 30 seconds.
Since the ECM can have
a failure which may
effect only one circuit, following the Diagnostic
Procedures in this section will determine which circuit
has a problem and where it is. If
a diagnostic chart indicates that the ECM
connections or ECM is the cause of
a problem and the
ECM is replaced, but does not correct the problem, one
of the following may be the reason:
€9
connections. - The diagnostic chart will say "ECM
connections or ECM. The terminals may have to be
removed from the connector in order to check them
properly.
@ The ECM or PROM is not correct for the
application.
- The incorrect components may cause a
malfunction and may or may not set a code.
@ The problem is intermittent. - This means that
the problem is not present at the time the system is
being checked. In this case, refer to the "Symptoms"
portion of the manual and make a careful physical
inspection of all portions of the system involved.
@ Shorted solenoid, relay coil, or harness. -
Solenoids and relays are turned "ON" and "OFF" by
the
ECM,using internal electronic switches called
"Drivers". Each driver is part of
a group of four called
"Quad-drivers". Failure of one driver can damage any
other driver in the set.
Solelloid and relay coil
resistance must measure more than 20 ohms. Less
resistance will cause early failure of the ECM
"driver". A shorted solenoid, relay coil, or harness,
with a GMP4 computer, will not damage the ECM, but
will cause the component to be inoperative.
Before replacing an ECM, be sure to check the coil
resistance of all solenoids and relays controlled by the
ECM. See ECM wiring diagram for the
solenoid(s)
and relay(s) and the coil terminal identification.
534636 or BT 8405 testers or equivalent provide
a fast, accurate means of checking for a shorted coil or
a short to battery voltage.
@ The PROM may be faulty. - Although these
rarely fail, it operates as part of the ECM. Therefore,
it could be the cause of the problem. Substitute a
known good PROM.
@ The replacement ECM may be faulty. - After the
ECM is replaced, the system should be rechecked for
proper operation. If the diagnostic chart again
indicates the ECM is the problem, substitute
a known
good ECM. Although this is a rare condition, it could
happen.
ECM
A faulty ECM will be determined in the diagnostic
charts or
by a Code 55.
PROM
A faulty PROM may result in a Code 51.

6E3-C1-6 2.8L (VIM O) DRlVEABlLlTY AND EMISSIONS
amportant
When replacing the production ECM with a
service ECM (controller), it is important to
transfer the Broadcast code and production
ECM number to the service ECM label. Please
do not record on ECM cover. This will allow
positive identification of ECM parts
throughout the service life of the vehicle.
amportant
To prevent internal ECM damage, the ignition
must be "OFF" when disconnecting or
reconnecting power to ECM (for example,
battery cable, ECM pigtail, ECM fuse, jumper
cables,
etc.).
ECM AND COMPONENTS REPLACEMENT
PROM OR ECM
Code 51 indicates a faulty PROM, possibly caused
by bent pins, or incorrect installation.
mmportant
It is possible to install a PROM backwards. If the
PROM
is installed backwards and the ignition key
turned to "ON," the PROM circuitry will be destroyed,
requiring PROM replacement.
NOTICE: The ignition should always be off when
installing or removing the ECM
connectors or internal components.
memove or Disconnect
1. Negative battery cable.
2. Right hand hush panel.
3. Connectors from ECM.
4. ECM mounting hardware.
5. ECM from passenger compartment.
6. ECM access cover (see Figure
C1-6).
7. Remove PROM assembly.
amportant
Using the rocker-type PROM removal tool,
enga& one end of t-hk PROM carrier with the
hook end of the tool (see Figure
C1-8). Press on
the vertical bar end of the tool and rock the
engaged end of the PROM carrier up as far as
possible. Engage the opposite end of the
PROM carrier in the same manner and
rock
this end up as far as possible. Repeat this
process until the PROM carrier and PROM are
free of the PROM socket.
The PROM carrier
with PROM in it Should lift off of the PROM
socket easily. PROM carrier should only
he
removed by using the pictured PROM removal
tool. Other methods could cause damage to the
PROM or PROM socket.
( ECM HARNESS
PROM CARRIER CONNECTORS TO ECM
1 PROM ACCESS COVER
Figure C1-6 PROM Access Cover
PROM CARRIER
PROM REMOVAL TOOL
Figure C1-7 PROM Removal Tool
Hnspect
1. New PROM for same part number as old.
Do not remove PROM from carrier to check PROM
number
2. For correct reference of PROM in carrier, Figure
C1-8.
3. CALPAK Assembly
Using the removal tool, pictured in Figure C1-9,
grasp the carrier
at the narrow ends. Gently rock the
carrier
from end to end while applying a firm upward
force and remove the CALPAK and carrier. Use of
unapproved
CAL,PAK removal tools or methods will
cause
damage to the CAI,PAK or CALPAK socket.

DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-C1-7
REFERENCE END
PROM PROM CARRIER
4S 81165-6E
Figure C1-8 PROM in PROM Carrier
mnstall or Connect
1. New PROM carrier in PROM socliet.
2. CALPAK in CALPAK socket.
mmportant
Small notch of carrier shoiild he aligned with
small notch in socket. Press on PROM carrier
until it is firmly seated in the socket. Do not press
on PROM; only the carrier.
3. Access cover on ECM.
4. ECRil in passenger compartment.
5. Connectors to ECM.
b A,' I
;,* fd I
: GRASP CALPAK 1% ,/w 1' CARRIERAT
[ZJ REMOVAL TOOL
Figure C1-9 Removing CALPAK
B. If Trouble Code 51 occurs or if the "Service
Engine Soon" light is on constantly with no
codes, the PROM is not fully seated, installed
backwards, has bent pins, or is defective. If
Code
52 occurs, the CALPAK is not fully
seated, installed backwards, has bent pins, or
is defective.
If not fully seated,
press firmly on PROM
or CALPAK carrier
a, If it is necessary to remove the PROM or
CALPAK, follow instructions in steps "A"
and
"B".
@ If installed backwards, REPLACE THE
PROM. The CALPAK may be removed
and reinstalled correctly.
@ If pins bend, remove PROM or CALPAK,
straighten pins, and reinstall. If
bent pins
break or crack during
straightening,
discard PROM or CtILPAK and replace it,.
am port ant
Any time the PROM in installed backwards and the
ignition switch turned
"ON," the f'I CALPAK see figure C1-9 or refer to step 3 of
PROM and ECM replacement.
COOLANT SENSOR
NOTICE:
Care must be taken when handling
coolant sensor.
Damage to coolant sensor
will affect proper operation of the Fuel
Injection
system.
B Remove or Disconnect
1. Negative buttery cable.
2.
Electricril connector.
3. Carefully back out coolant sensor.
a ln,aIl
1. Sensor in
or Connect
engine.
2. Electrical connector.
3. Negative battery cable.
MAF SENSOR
Functional Check
Replacement of the iL'IAF xcnsor is shown in
Figure C1-10. When
replacing the MAF sensor,
1. Turn ignition on.
replace cla~llps with special hcrew type cla~rlps
2. Enter diagnostics (see Diagnostic Circuit Check (Service Part).
for procedure).
A. Code 12 should flash at least four times. (Yo MAF SENSOR POWER & BURN-OFF RELAY
other codes present). This indicates the PIIOM
and CALPAK is installed properly.
Refer to Figure C 1- 1 1 for relay location. 'rhe MAF
power relay is to the right ofthe radiator

6E3-CZ-4 Z.8L (WIN 5) DRIVEABILITY AND EMISSIONS
FUEL INJECTOR
1 INTAKE MANIFOLD
1 INTAKE VALVE
1 ELECTRICAL TERMINAL
151 "0" RING
1 FUEL RAIL 4.5 101ME
Figure C2-4 Fuel Injector
The pressure regulator is mounted on the fuel rail,
and is replaced as an assembly.
If the pressure is too low, poor performance could
result. If the pressure is too high, excessive odor and a
Code
45 may result. CHART A-7 has information on
diagnosing fuel pressure conditions.
IDLE AIR CONTROL (IAC) VALVE
The purpose of the idle air control (IAC) valve
(shown in Figure C2-5), is to control engine idle speed,
while preventing stalls due to changes in engine load.
The IAC valve, mounted in the throttle body,
controls bypass air around the throttle valve. By
moving a conical valve IN
(to decrease air flow) or
OUT (to increase air flow), a controlled amount of air
can move around the throttle plate. If rprn is too low,
more air is bypassed around the throttle valve to
increase rpm. If rprn is too high, less air is bypassed
around the throttle valve to decrease rpm.
The IAC valve moves in small steps called
"counts," which can be measured by some test
equipment which plugs into the ALDL.
During idle, the proper position of the IAC valve is
calculated by the ECM based on battery voltage,
coolant temperature, engine load, and engine rpm.
If
the rprn drops below a specified rpm, and the throttle
plate is closed, the ECM senses a near stall condition.
SINGLE TAPER VALVE
DUAL TAPER VALVE
BLUNT
PINTLE
Figure C2-5 IAC Valve Designs
The ECM will then calculate a new valve position to
prevent stalls.
If the IAC valve is disconnected and reconnected
with the engine running, the idle rprn may be wrong.
In this case, the IAC can be reset by starting the
engine momentarily and then turning the ignition
"OFF".
Different designs are used for the IAC valve. Re
sure to use the correct design when replacement is
required.
The IAC valve affects only the idle characteristics
of the vehicle. If it is open fully, too much air will be
allowed into the manifold and idle speed will be high.
If it is stuck closed, too little air will be allowed in the
manifold, and idle speed will be too low. If it is stuck
part way open, the idle may be rough, and will not
respond to engine load changes.
FUEL PUMP ELECTRICAL CIRCUIT
When the ignition is first turned "ON" without
the engine running, the ECM will turn the fuel pump
relay
"ON" for two seconds. This builds up the fuel
pressure quickly. If the engine is not started within
two seconds, the ECM will shut the fuel pump
"OFF"
and wait until the engine starts. As soon as the
engine is cranked, the ECM will turn the relay
"ON"
and run the fuel pump.

6E3-C2-6 2.8L (VIN 5) DRIVEABILITY AND EMISSIONS
FUEL RAIL ASSEMBLY
Figure C2-6 Plenum and Fuel Rail Removal
Important
At any time the fuel system is opened for service,
the O-ring seals used with the related
component(s) should be replaced.
Remove or Disconnect
1. Negative battery cable.
2. Plenum.
3. Fuel lines.
4. Cold start valve.
5. Vacuum line at pressure regulator.
6. Fuel rail retaining bolts
7. Injector harness connectors.
8. Rail and injectors.
install or Connect
1. Coat injector "On-rings with engine oil.
2. Rail and injectors.
3. Injector harness.
4. Fuel rail retaining bolt.
5. Vacuum line at pressure regulator.
6. Cold start valve.
7. Fuel lines.
8. Plenum.
9. Negative cable
10. Cycle the ignition on and off several times and
inspect fuel system for leaks.
FUEL RAIL SERVICE
Names of component parts will be found on the
numbered list that accompanies the exploded view
(Figure C2-9). Numbers used to identify parts on the
exploded view will identify the same parts in other
illustrations of this section.
An eight digit identification number is stamped
on the side of the fuel rail assembly, as shown in
Figure C2-7. Refer to this number if servicing or part
replacement is required.
Figure C2-7 Fuel Rail Assembly [dentification
UNIT SERVICE PROCEDURES
Important
When servicing the fuel rail assembly,
precautions must be taken to prevent dirt and
other contaminants from entering the fuel
passages. It is recommended that fittings be
capped, and holes be plugged, during servicing.

ELECTRONIC VACUUM REGULATOR VALVE
Remove or Disconnect
1. Negative battery cable.
2, Electrical connector at regulator valve
3. Vacuum hoses.
4. Nut and regulator valve.
Install or Connect
1. Regulator valve and bracket, tighten nut to
24 N . m (17 lb. ft.).
2. Vacuum hoses
3. Electrical connector
4. Negative battery cable
EVRV FILTER REPLACEMENT
The EVRV filter should be replaced every 30, 000
miles.
1. Grasp and pull filter "OFF" with a rocking motion.
2. Push A ew filter "ON", making sure cut-out for
wires is properly aligned.
PARTS INFORMATION
PARTS NAME GROUP
........................ Valve, ECR :; ri70
.................. Gasket, EGIt VaI~re ;I (i8O
................ Control, EGR Vacuium :i.i;i'O

DRIVEABILITY AND EMlSSlONS 2.8L (VIN %I 6E3-C8-1
TRANSMISSION CONVERTER CLUTCH (KC) SYSTEM
AND MANUAL
TRANSMISSION SHIFT LIGHT
CONTENTS
GENERAL DESCRIPTION ................ C8-1 DIAGNOSIS ..........ee...ee....e.e. C8-1
PURPOSE ......................... C8-1 SHIFT LIGHT (MIT) DESCRIPTION ........ C8-1
OPERATION ....................... C8-1 DIAGNOSIS ....................... .. C8-1
ON-CAR SERVICE ...................*. C8-1
GENERAL DESCRIPTION
PURPOSE
The transmission converter clutch (TCC) svstem
uses a solenoid operated valve in the automatic
transmission to couple the engine flywheel to the
output shaft of the transmission thru the torque
converter. This reduces the slippage losses in the
converter, which increases fuel economy.
OPERATION
For the converter clutch to apply, two conditions
must be met:
o Internal transmission fluid pressure must be
correct. For information on internal transmission
operation, see Section
"7A". This section will cover
only the electrical operation of the TCC system.
@ The ECM grounds a switch internally to turn on a
solenoid in the transmission. This moves a check
ball, which will allow the converter clutch to
apply, if the hydraulic pressure is correct, as
described above.
The ECM controls the TCC apply solenoid by
looking at several sensors:
@ Speedo Buffer Sensor (also called vehicle speed
sensor
(VSS). Speed must be above a certain value
before the clutch can apply.
@ Coolant Temperature Sensor. Engine must be
warmed up before clutch can apply about
65OC
(149°F').
Throttle position sensor ('I'PS). After the
converter clutch applies, the
HCM uses the
information from the TPS to release thc clutch
when the car is accelerating or decelerating at a
certain rate.
@ 'I'he brake switch is also part of the 'I'CC circuit as
it will remove battery voltage to the 'KC solenoid
when the brake pedal is depressed.
@ Gear Select Switch. The 4th gear switch is used 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.
IIowever, the
transmission does not have to be in fourth gear in
order for the ECM to turn the clutch on.
If the converter clutch is applied at all times. the
engine will stall immediately, just as in
u manual
transmission with the clutch applied.
If the converter clutch does not apply, fuel
ecomony
may be lower than expected. If the vehicle
speed sensor fails, the TCC will not apply. If the 4th
gear switch does not operate, the TCC may not apply
at the right time.
DIAGNOSIS
The diagnosis of the TCC system is covered in
CHART C-8
. If the ECM detects a problem in the
system,
a Code 24 should set. In this case see Code 24
CHART.
SHIFT LIGHT (MiT) DESCRIPTION
'The purpose of the shift light is to provide a
display which indicates the optimum fuel economy
point for up
shifling the manual transmission based
on engine speed
and load. 'I'he display is a lamp on the
instrument panel. Activation of the ECM driver turns
the lamp
on.
'I'he shift light circuit can he checlted using
CHAR?' C-8C.
ON-CAR SERVICE
@ See Section "8B" if the shift light bulb needs
replacement.
@ See Section "6E" to repair wiring problem.
@ See Section "6C" if ECM is to be replaced.

6E3-A-8 5.OL (VIN F) & 5.7L(VIN 8) DRIVEABILITY AND EMISSIONS
DIAGNOSIC CIRCUIXCHECK
The Diagnostic Circuit Checlc is an organized approach to identifying a problem created by an Electronic
Engine Control System malfunction. It
must be the starting point for any driveability complaint diagnosis,
because it directs the Service Technician to the next logical step in diagnosing the complaint.
The "Scan Data" listed in the table may be used for comparison, after completing the Diagnostic Circuit
Check and finding the on-board diagnostics functioning properly and no trouble codes displayed. The "Typical
Values" are an average of display values recorded from normally operating vehicles and are intended to
represent what a normally functioning system would typically display.
A "SCAN" TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM
SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY "SCAN" CAN RESULT
IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.
Only the parameters listed below are used in this manual for diagnosing. If a "Scan" reads other parameters,
the values are not recommended by General Motors for use in diagnosing. For more description on the values
and use of the "Scan" to diagnosis ECM inputs, refer to the applicable diagnosis section in Section C.
If all values
are within the range illustrated, refer to symptoms in Section
B.
"SCAN" DATA
Idle / Upper Radiator Hose Hot / Closed Throttle / Park or Neutral /Closed Loop /Acc. off
"SCAN" Position Units Displayed Typical Data Value
Desired RPM RPM ECM ~dle command (vanes w~th temp.)
RPM RPM
+ 100 RPM from desired RPM ( k 50 ~n drive)
Coolant Temp.
CO 85" - 105"
MAT Temp. CO 10" - 90" (depends on underhood temp.)
MAF G
m/Sec 4-7
Air Flow
Gm/Sec 4 - 7
BPW (base pulse width)
M/Sec 1 - 4 and varying
02 Volts 1 - 1000 and varying
TPS Volts 46 - .62
I AC Counts (steps)
5 - 50
INT (Integrator) Counts
Vanes
BLM (Block Learn) Counts 118- 138
Open/Closed Loop Open/Closed Closed Loop (may go open with extended idle)
BLM Cell Cell Number
0 or 1 (depends on Air Flow & RPM)
VSS MPH 0
TCC
On/Off Off/ (on wlth TCC commanded)
Battery Volts 13.5
- 14.5
PPSW
Volts 13.5- 14.5
LV8 Counts 30
- 60
Knock Retard Degrees
of Retard 0
Spark Advance
# of Degrees Varies
PIN
Swltch PIN and RDL ParkINeutral (PIN)
A.I. R. Control
Normal/Divert Normal
A.I.R. Switch
PortIConverter Converter
NC Request Yes/No No (yes, wlth NC requested)
Fan Request
Yes/No No (yes, with NC high pressure)
EGRDC 0- 100%
0 at idle
EGR Diagnostic
On/Off off
Fan
OnIOff Off (below 108°C)
CCP duty cycle 0
- 100% 0
Knock Signal
YesINo No (yes, when knock is detected)
Shift Light
(MIT) On/Off Off
4th Gear
Yes/No No (yes, when in 4th gear)