PONTIAC FIERO 1988 Service Repair Manual

6E3-6 2.8L (VIN S). 5.OL (&BIN F) & 5.7L (WIN 8) BRllVEABlhlPY AND EMISSIONS
......... Fuel Pump Electrical Circuit C2-5
DIAGNOSiS ......................... CZ-5
.............. FUEL CONTROL SYSTERA C2.5
............ IDLE AIR CONTROLVALVE CZ-5
......... FUEL SYSTEM PRESSURE TEST C2-5
ON-CAR SERVICE ..................... C2-5
PORT FUEL INJECTION COMPONENTS .... Cf-5
FUEL PRESSURE RELIEF PROCEDURE ..... C2-5
Plenum ......................... C2-5
................ FUEL RAILASSEMBLY CP-6
FUEL RAIL SERVICE ................... C2-7
................... IDENTIFICATION C2-7
........... UNIT SERVICE PROCEDURES C2-7
COLD START .TUBE & VALVE ASSEMBLY ... ~2-7
PARTS INFORMATION ............... CZ-9
.... FUEL PRE5Si.J RE COPdNECl'ION ASSY C2-10
FUEL INJECTORS (Rail Removed) ........ C2-10
PRESSURE REGULATOR (Ball Removed) ... C2-10
COLD START FUEL INJEClION SWITCH ... C2-1%
THROTTLE BODY ................... CZ-11
VWROTTLE BODY SERVICE IDENTIFICATION . C2-12
............ UNIT REPAIR PROCEDURES Cf-112
TPS Adjcistment .............. C2-12
MiNIRilUM IDLE SPEED CHECK ........... CE-'I2
................. PARTS INFORMATION C2-15
IDLE AIR C'NT' L VALVE ASSY (3r: GASKET . . C2-15
CLEAN AIR COVER & GASKET .......... C2-15
SECTION C4 . 5.0h (VIN F) & 5.7L (VIN 8)
lGNITlON SYSTEMIEST
................ GENERAL DESCRIPTION C4-1
......................... PURPOSE C4-1
OPERATION ....................... C4-1
RESULTS OF INCORRECT OPERATION .... C4-1
......................... DIAGNOSIS C4-1
CODE 12 .......................... C4-1
ON-CAR SERVICE ..................... C4-2
SETTING TIMING .................... C4-2
HOW CODE 42 IS DETERMINED ......... C4-2
................. PARTS INFORMATION C4-2
lgn~tion System Check
Chart C-4
......................... C4-4
SECTION C5 . 5.0L (VIM F) & 5.7L JVIN 8)
ELECTRONIC SPARK CONTROL (ESC) SYSTEM
................ GENERAL DESCRIPTION C5-1
......................... PURPOSE C5-1
.............. GENERAL DESCRIPTION C5-1
......................... DlAGNOSiS C5-1
..................... ON-CAR SERVICE C5-1
....................... ESCSENSOR 65-1
.......... E4C MODULE AiYD BRACKET 165-2
................. PARTS INFORMATXBM C5-2
Electronic Spark Control
Chiirt C-5 ......................... C5-4
IDLE AIR CBi\~TROVCOOLANl'CVR . AS57 0
Throlrle Body Reinovecl Froti.1 Engine . .
FUEL PUlVlP RELAY ..................
................ OIL PRESSURE 5WETCI-I
P/%RVS INFORMATION .................
Irilector Halarlce Test
Chart
C-2A ........................
Idle Air Control
Chart
C-%C ........................
C2-I 5 SECYlOM Ct; . 5.0L (VlN F) & 5.7L (VIN 8)
62-1 5 A8W INJECTION REACTION (A.I.R.) SYSTEM
C2-16 GENERAL DESCRbPTION ............... CG-I
C2-16 PURPOSE ....................... C6-1
C2-76 OPE RATION ...................... C6-1
AIR COPJTROL PEDES VALVE ......... C6-I
C2-'18 RESULTS OF INCORRECT OPERATION .... C6-2
DIAGNOSIS ........................ C6-2
............. Cf -20 OPERATIONAL CHECKS C6-2
SbCTIBN C3 . 5.0L (VIN F) h 5.7L (V1N 8)
I:itAPORAIIVE EMISSlON CONTROL (EECS) SYSTEM
LZNERA. L DESCRIP'rION ............... C3-'!
PURPOSE ........................ C3-1
VAPOR CANISTER
.............. $3-1
EVAF'OFt/?ITIVE EMISSION SYSTEM .me.e. C3-4
FUEL TANK PRESSURE CONTROL VALVE . . C3-2
IN-'TANK PRESSURE CONTROL VALVE . . 63-2
RESULTS OF IRiCORRECT OPERATIGN .... C3-2
DIAGNOSIS ........................ C3-2
VISUAL CHECK OF CANIS'rkR .......... C3-2
FUNCPIONAL TEST
Vapor
Can~saer Purge Valve ........ C3-9
Tank Pressure Control Valve ..... C3-2
ON-CAR SERVICE ................. C3-3
FUEL VAPOR CANISTER ............ C3-3
CANISTER HOSES.
................... C3-3
PARTS INFORiblAT%BN ................ C3-3
Canister Purge Valve Check
Chart
C-3 ......................... C3-4
...................... Air Pump C6-2
................. Hoses and Pipes C6-3
.................... Check \/alve C6-3
.................... ON-CAR SERVICE C6-3
...................... DRIVE BELT C6-3
AIR INJECTION PUMP ............... C6-3
AIR INJECTION CONTROL
.................. (PEDES) VALVE C6-3
AIR ~NJECTION CIIECK VALVE ......... ~6-4
................ PARTS INFORMATION C6-4
AIR Management Check (PEDES)
........................ Chart C-6 C6-6
SECTlON C7 . 5.OL (VlN F) & 5.7L (VIN 8)
EXHAUST GAS RECIRCULATION {EGR) SYSTEM
GENERAL DESCRIPI'ION ..............*. C7-1
......................... PURPOSE C7-I
OPERATION
....................... C7-1
EGR
CONTROL .................... C7-1
NEGATIVE BACKPRESSURE EGR VALVE . . C7-2
EGR \/ALVE IDEhITIFICATION ........... C7-2

DRIVEABILITY AND EM10010NS 2.8L (WIN S). 5.8L (VIN F) & 5.7L (VlN 8) 6E3-7
RESULTS OF INCORRECT OPERATION ..... C7-2
DIAGNOSIS
....................... C7-2
EGRVALVE ...................... 0-3
EGR Manifold Passage ............... C7-3
EGR CONTROL SOLENOID ............ C7-3
PARTS INFORMATION
................. C7-3
Exhaust Gas Recirculation Check
Chart C-7
......................... C7-4
SECTION
C8 . 5.01 (VIN F) & 5.7L (VIN 8)
TRANSMISISON CONVERTER CLUTCH (TCC) SYSTEM
AND MANUAL TRANSMISSION SHIFT LIGHT
GENERAL DESCRIPTION
................ C8-1
PURPOSE ......................... C8-1
OPERATION ....................... C8-1
DIAGNOSIS ......................... C8-1
SHIFT LlGHT(M1T) DE5CRlPTlON ........ C8-1
DIAGNOSIS ......................... C8-1
ON-CAR SERVICE
..................... C8-1
Automatic Transmission
Converter Clutch
(TCC) (1 of 2)
Chart C-8A ........................ C8-2
MIT Shift Light Check
Chart C-8B
........................ C8-6
SECTION C12 . 5.OL (WIN F) & 5.7L (WIN 8)
eoOLlNe FAN CONTROL
GENERAL DESCRIPTION ................ C12-1
OPERATION ....................... C12-1
DIAGNOSIS ................... .. .... C12-1
ON-CAR SERVICE ..................... C12-1
PARTS INFORMATION .*............... ~12-1
Cooling Fan Control Circuit (I of 2)
Chart C-12 ........................ C12-2
Cooling Fan Control Circuit (2 of 2)
Chart C- 12 ........................ C9 2 -4
SECTION C13
. 5.OL (VIN F) & 5.7L (VIN 8)
POSITIVE CRANKCASE VENTILATION (PCV)
GENERALDESCRIPTION ................ 643-1
RESULTS OF INCORRECT OPERATION .... 613-9
DIAGNOSIS ......................... C13-1
FUNCTIONAL CHECK OF PCV VALVE .... C13-4
ON-CARSERVICE ..................... C13-2
PARTS INFORMATION ................. C13-2

6E3-8 2.8L (VIM $1, 5.OL (VIN F) & 5.7L(VlN 8) BRlVEABILlTY AND EMISSIOMS
ALL NEW GENERAL MOTORS VEHICLES ARE CERTIFIED BY THE UNITED STAEES
ENVIRONMENTAL PROTECTION AGENCY AS CONFOWMlNG TO "THE REQUIREMENTS QF THE
REGULATIONS FOR THE CONTROL OF AIR POLLUTION FROM NEW MOTOR VEHICLES. THIS
CERTlFlCATlON IS CONTINGENT ON CERTAIN ADJUSTMENTS BEING SET TO FACTORY
STANDARDS. IN MOST CASES, THESE ADJUSTMENT POINTS EITHER HAVE BEEN
PERMANENTLY SEALED ANDIOR MADE
INACCESSlBLE TO PREVENT INDISCRIMINATE OR
ROUTINE ADJUSTM&M"FIN 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 QF THE DESIGN.
INTRODUCTION
GENERAL BESCRIPT18N DIAGNOSIS PROCEDURE
This section applies to engines which have a fuel
injector in the intake manifold near the intake valve
for each cylinder. It is commonly referred to as "Port
Fuel Injection".
These engines have controls to reduce exhaust
emissions, while maintaining good driveability and
fuel economy.
An engine control module
(ECM) is the heart of
this control system and has sensors used to provide
information about engine operation and the various
systems it controls. Details of basic operation,
diagnosis, functional checks, and on-vehicle service
are covered in Section "C", "Component Systems".
The ECM has the ability to do some diagnosis of
itself, and of other parts of the system. When it finds a
problem, it lights a "Service Engine Soon" light on the
instrument panel and
a trouble code will be stored in
the ECM memory. This does not mean that the engine
should be stopped right away, but that the cause of the
light coming
"ON" should be checked as soon as
reasonably possible. The
following
sections(s) are written for specific
engine applications and are clearly indentified. Be
sure to use only the section which applies to the
engine family being diagnosed.
Before using this section of the manual, you
should be familiar with the information and the
proper diagnosing procedures as described in Section
"GE". If the proper diagnosis procedures are not
followed, as described in Section
"6EM, it may result in
unnecessary replacement of good parts.
Trouble tree charts incorporate diagnosis
procedures using an ALDL "SCAN" tool where
possible.
The "SCANJ' tool has the ability to save time
in diagnosis and prevent the replacement of good
parts. The
key to using the "SCAN" tool
successfully for diagnosis lies in the technician's
ability to understand the system he is
trving to
diagnose. as well as an understanding of the
"SCAN" tool's limitations. See Section "6E" for
more information.

DRIVEABILITY AND EMISSIONS f.8b (VIN S) 6E3-A-1
Cold Oxygen Sensor
The "Diagnostic Circuit Check" verifies the On some engines.
the oxygen sensor will cool off
system is functioning correctly . some special after only a short period of operation at idle . This will
considerations to keep in mind while making the put the system into "Open Loop" . To restore "Closed
"Diagnostic Circuit Check" are: Loop"
operation. run the engine
at part throttle
several minutes and accelerate from idle to part
Blocking Drive Wheels throttle a few times .
The vehicle drive wheels should always be blocked Basic Procedure
while checking the system . If you have not reviewed the basic information on
how to
use the diagnostic procedures. go to the
introduction of this section
.
ENGINE COMPONENTS /WIRING DIAGRAMS / DIAGNOSTIC CHARTS
ComponentLocations ........................................................ PageA-2
Wiring Diagrams (1 of 3) ...................................................... Page A.3.4. 5
ECM Connector Terminal End View
.............................................. Page A-6
Diagnostic Circuit Check
...................................................... Page A-8
No "Service Engine Soon" bight
. Chart A-1 ........................................ Page A-10
No
ALBL or Won't Flash Code 12 . "Serv~ce Engine Soon" Light On Steady . Chart A-2 ........ Page A-12
. Engine Cranks But Won't Run Chart A-3 (1 of 2) .................................... Page 8-14
. Fuel System Diagnosis Chart A-7 (1 of
2) .......................................... Page A-18
Cold Start Valve
. Chart A-9 .................................................... Page A-22
Code 13 Oxygen Sensor Circuit (Open Circuit)
...................................... Page A-24
Code 14 Coolant Temperature Sensor Circuit (High Temp
. Indicated) ..................... Page A-26
Code 15 Coolant Temperature Sensor Circuit (Low Temp
. Indicated) ..................... Page A-28
Code 21 Throttle Position Sensor (TPS) Circuit (Signal Voltage High)
...................... Page A-30
Code 22 Throttle Position Sensor (TPS) Circuit (Signal Voltage Low)
...................... Page A-32
Code 23 Manifold Air Temperature (MAT) Sensor Circuit (Low Temp
. Indicated) ............ Page A-34
Code 24 Vehicle Speed Sensor (VSS) Circuit
........................................ Page A-36
Code
25 Manifold Air Temperature (MAT) Sensor Circuit (High Temp . Indicated) ............ Page A-38
Code 32
EGR System Failure .................................................... Page A-40
Code 33 Mass Air Flow (MAF) Sensor Circuit
(GMISEC High) ............................. Page A-42
Code 34 Mass Air Flow (MAF) Sensor Circuit
(GMISEC bow) ............................. Page 8-44
Code
41 Cylinder Select Error .................................................. Page A-46
Code 42 Electronic Spark Timing Fault
................... .... .................... Page 8-48
Code 44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
.............................. Page A-50
Code
45 Oxygen Sensor Circuit (Rich Exhaust Indicated) ............................... Page A-52
Code 54 Fuel Pump Circuit
(Lowvoltage) .......................................... Page A-54
Code
51 PROM Error (Faulty or Incorrect PROM) ..................................... Page A-56
Code 52 CALPAK Error (Faulty or Incorrect CALPAK)
................................. Page 44-56
Code 53 System Over Voltage .................................................. Page A-56
Code55ECMError ............................O.~o.~.~e.~e~e.~e....... .. PageA-56

6E3-A-2 2.88, (VIM S) DRIVEABILITY AND EMISSIONS
'Fa SERIES
COMPUTER HARNESS
C1 Electronic Control Module (ECM)
C2 ALDL diagnostic connector
C3 "SERVICE ENGINE
SOON" light
C4 ECM powerlfuel pump fuse
C5 ECM harness ground
C6 Fuse panel
C8 Fuel pump test connector
(ALDL"G")
C9 MAFfuse
CONTROLLED DEVICES
1 Fuel injector
2
Idle air control motor
3 Fuel pump relay
5 Trans. Conv. Clutch connector
6a Remote ignition coil
8 Engine coolant fan relay
9 Air control solenoid (M.T. only)
12 Exhaust Gas Recirculation solenoid
0 INFORMATION SENSORS
B Exhaust oxygen
C Throttle position D Coolant temperature
F Vehicle speed
K Mass Air Flow
S Power steering pressure switch
T Manifold Air Temperature
U AIC pressure fan switch
13 AIC compressor relay
,..,a :'"' NOT ECM 'ONNECTED 15 Fuel vapor canister solenoid N1 Crankcase vent valve (PCV) 17 bass air flow sensor relay N4 Engine temp. switch (telltale)
N5 Engine temp. sensor (gage) Exhaust Gas Recirculation valve
N6 Oil press. switch (telltale)
N7 Oil press, sensor (gage)
N8 Oil press. swich (fuel pump)
N10 Cold start fuel injection switch
N11 Cold start valve 7-29-87 N12 Deceleration Valve (MIT only)
N13 Fan Override Switch *5S 2127-6E
Figure Al-l - Component Locations 2.8L "F" Series

BRlVEABlLlTY AND EMISSIONS 2.8L (VIN 5) 6E3-A-3
ENGINE GND'S BACK VIEW
OF
CONNECT OR
TO VSS BUFFER
OXYGEN SENSOR
ENGINE GND.
MANIFOLD AIR
TEMPERATURE
4 WAY INJ.
JPR. CONN.
7-14-87
Figure A1-2 -Wiring Diagram 2.8L "F" Series (1 of 3)

6E3-A-4 2.8L (VIN S) DRIVEABILITY AND EMISSIONS
ECMIIGN
I I
I
1
I
I
I I
I
PRIMARY COIL I
I
I
I
I
FUEL PUMP
CONNECTOR FUEL
FUEL PUMP SIGNAL

DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-A-5
ECM
BRAKE SWITC
BACK
VIEW OF
AIR DIVERT SOLENOID
MANUALITRANS
IGNITION 12V
TANMIHT 250 ALTERNATOR
Figure A1-4 - Wiring Diagram 2.8L "F" Series (3 of 3)

DRIVEABILITY AND EMISSIONS f.8L (VIM 9) 6E3-A-7
BLANK