PONTIAC FIERO 1988 Service Repair Manual

6E3-C12-6 2.8L (VIN 5) DRIVEABILITY AND EMISSIONS
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DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-C13-1
SECTION C13
POSITIVE CRANKCASE VENTILATION (PC\/)
.... GENERAL DESCRIPTION ................ C13-1 FUNCTIONAL CHECK OF PCV VALVE C13-1
RESULTS OF INCORRECT OPERATION .... C13-1 ON-CAR SERVICE ..................... C13-2
DIAGNOSIS
......................... C13-1 PARTS INFORMATION ................. C13-2
GENERAL DESCRIPTION 4. Turn "OFF" the engine and remove PCV valve.
Shake valve and listen for the rattle of check
A "closed" crankcase ventilation (PCV) system is needle inside
the valve. If valve does not rattle,
used to provide more complete scavenging of replace
v4 ~1 1 ve.
crankcase vapors. Fresh air from the air cleaner is With this
system, any blow-by in excess of the
slipplied to the crankcase, mixed with blow-by gases system capacity (from a badly-worn engine, sustained
and then passed through a positive crankcase heavy load, etc.) is exhausted into the air cleaner and
ventilation
(PCV) valve into the intake manifold isdrawn into theengine.
(Figure C13-1).
The primary control is through the PCV valve
(Figure
(213-2) which meters the flow at a rate
depending on manifold vacuum.
To maintain idle quality, the PCV valve restricts
the flow when intake manifold vacuum is high. If
abnormal operating conditions arise, the system is
designed to allow excessive amounts
of I,low-by gases
to back flow through the crankcase vent tube into the
engine air inlet to be consumed by normal combustion.
RESULTS OF INCORRECT OPERATION
A plugged valve or hose may cause:
@ Rough idle.
@ Stalling or slow idle speed.
@ Oil leaks.
@ Sludge in engine.
A leaking valve or hose would cause:
@ Rough idle.
@ Stalling.
@ Iiigh idle speed.
DIAGNOSIS
FUNCTIONAL CHECK OF PCV VALVE
If an engine is idling rough, check for a clogged
PCV valve or plugged hose. Replace as required. Use
the following procedure:
1. Remove PCV valve from rocker arm cover.
2. Run the engine at idle.
3. Place your thumb over end of vi~lcce to check for
vacuum. If there is
no vacuum at valve, chcck for
plugged hoses or
lrlanifold port, or 1'CV valve.
Replace plugged or dcterioratcd hoses.
a CLEAN AIR
VOLATILE OIL FUMES
---e- MIXTURE OF AIR AND FUMES
PCV VALVE
1 TO THROTTLE BODY
CRANKCASE VENT HOSE
1 PCV VALVE HOSE
150 INTAKE MANIFOLD
Figure C13-1 PCV Flow

6E3-C13-2 2.8L (VIN 5) DRIVEABILITY AND EMISSIONS
Proper operation of the PCV System is dependent ON-CAR SERVICE
upon a sealed engine. If oil sludging or dilution is
noted, and the PCV System is functioning properly,
An engine which is operated without any
check engine for possible cause and correct
to ensure crankcase ventilation can be damaged. Therefore, it is
that system will function as intended.
important to replace the PCV valve at
intervals
shown in Section
"OB".
Periodically, inspect the hoses and clamps and
replace any showing signs of deterioration.
I I PARTS INFORMATION
PART NAME GROUP
Figure C13-2 PCV Valve Cross Section
......................... Air Cleaner 3.402
............... Valve Asm, C/Case Vent 1.745
.................... Tube, C/Case Vent 1.762
................ Hose, C/Case Vent V 1 v 1.762
.................. Breather, NC and Sil 3.410

DRIVEABILITY AND EMISSIONS 5.OL (VIM F) & 5.7L(VIN 8) 6E3-A-1
DIAGNOSIC CIRCUIT CHECK 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:
I. oop" 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 must be blocked while Basic Procedure
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
.
SECTION A
ENGINE COMPONENTS
/WIRING DIAGRAMS 1 DIAGNOSTIC CHARTS
........................................................ Component Locations Page A-2
...................................................... Wiring Diagrams. (1 of 4) Page
A-3
ECMTerminal EndView ...................................................... PageA-7
.................................................. Scan Diagnostic Circuit Check Page
A-8
........................................ . No "Service Engine Soon" Light Chart A-I Page A-10
No ALDL Data
. "Service Engine Soon" Light On Steady (Won't Flash Code 12) . Chart A-2 ..... Page A-12
................................... . Engine Cranks But Won't Run Chart A.3, (1 of 2) Page A-14
......................................... Fuel System Diagnosis . Chart A.7, (1 of 2) Page
A-18
.................................................... . Cold Start Valve Chart A-9 Page A-22
..................................................... Code 13 O2 Sensor Circuit Page
A-24
.................................. Code 14 Coolant Temperature Sensor Circuit (High) Page
A-26
.................................. Code 15 Coolant Temperature Sensor Circuit (Low) Page
A-28
................................. Code 2 I Throttle Position Sensor (TPS) Circuit (High) Page
A-30
.................................. Code 22 Throttle Position Sensor (TPS) Circuit (Low) Page
A-32
......................... Code 23 Manifold Air Temperature (MAT) Sensor Circuit (Low) Page
A-34
........................................ Code 24 Vehicle Speed Sensor (VSS) Circuit Page
A-36
......................... Code 25 Manifold Air Temperature (MAT) Sensor Circuit (High) Page
A-38
..................................... Code 32 Exhaust Gas Recirculation (EGR) Circuit Page
A-40
................................... Code 33 Mass Air Flow (MAF) Sensor Circuit (High) Page
A-42
................................... Code 34 Mass Air Flow (MAF) Sensor Circuit (Low) Page
A-44
................................. Code 36 Mass Air Flow (MAF) Sensor Burn-Off Circuit Page
A-46
................................................... Code 41 Cylinder Select Error Page
A-48
...................................... Code 42 Electronic Spark Timing (EST) Circuit Page
A-50
...................................... Code 43 Electronic Spark Control (ESC) Circuit Page
A-52
............................................ Code 44 Oxygen Sensor Circuit (Lean) Page
A-54
............................................. Code 45 Oxygen Sensor Circu~t (Rich) Page
A-56
......................................... Code 46 Vehicle Anti Theft System (VATS) Page
A-58
Code51
MEM.CAL ........................................................... PageA-62
........................................................ Code52CALPAKError PageA-62
................................................... Code 53 System Over Voltage Page
A-62
................................................ Code 54 Fuel Pump Circu~t (Low) Page
2-60

6E3-A-2 5.OL (VIN F) & 5.7L(VIN 8) DRIVEABILITY AND EMISSIONS
COMPUTER HARNESS [7 CONTROLLED DEVICES 0 INFORMATION SENSORS
C1 Electronic Control Module (ECM) 1 Fuel injector €3 Exhaust oxygen
C2 ALDL diagnostic connector 2 Idle air control motor C Throttle position
C3 "SERVICE ENGINE SOON" light
3 Fuel pump relay D Coolant temperature
C4
ECMpower 5 Trans. Converter Clutch connector F Vehicle speed
C5 ECM harness ground
7 Electronic Spark Control module J ESCknock C6 Fuse panel
C8 Fuel pump test connector (ALDL "G") Primary fan relay K Mass Air Flow
C9 Fuel pump1ECM fuse 9 Air injection converterldivert solenoid T Manifold Air Temperature
10 Air injection port solenoid
U AIC pressure fan switch . ., .. .. NOT ECM CONNECTED 12 EGR vacuum solenoid w EGR temp. diagnostic switch
N1 Crankcase vent valve (PCV) 15 Fuel vapor canister solenoid
N5 Engine temp. sensor (gage overheat)
16 MAF sensor power relay
N7 Oil pressure sensor (gage) 17 MAF sensor burn-off relay
N8 Oil pressure switch (fuel pump) 18 Primary cooling fan
N10 Cold start valve
N11 Cold start fuel injection switch
N12 Secondary cooling fan
N13 Cooling fan temperature switch
N14 Secondary cooling fan relay 7-13-87
*8S 4274-6E
Figure A-I - Component
Locations - 5.OL (WIN F) & 5.7L (WIN 8) "F" Series

DRIVEABILITY AND EMISSIONS 5.OL (VIN F) & 5.7L (VIN 8) 6E3-A-3
- ORN 461
T
TO MAF AND FUEL
PUMP RELAY AND
FAN CONTROL
SWITCH
ALDL CONN
I ENGINE
ENGINE GROUND
GROUND
-
OXYGEN SENSOR
TAN 413
MANIFOLD AIR TAN 472
TEMPERATURE SENSOR
GRY
416
K BLU 417
BLK 452
COOLANT
TEMPERATURE
SENSOR
YEL4lO
PICK-UP COlL
PRIMARY COlL I ..
- WHT
PPWHT
TANJBLK
BLWRED SERIAL
DATA
DIAGNOSTIC TEST
SYSTEM GROUND
SYSTEM GROUND
BACK
SYSTEM GROUND OF
CONNECTOR
OXYGEN SENSOR
SIGNAL
OXYGEN SENSOR
GROUND
24 PIN
A-0 CONNECTOR
MAT SENSOR
SIGNAL
BACK
VIEW OF
CONNECTOR
+ 5V REF.
TPS SIGNAL
5V RETURN
COOLANT TEMP.
SIGNAL
32 PIN C-D
CONNECTOR
EST
REFERENCE
BY-PASS
DISTRIBUTOR GROUND
8s 4240
7-13-87

6E3-A-4 5.OL (VIN F) & 5.7L (VIN 8) DRIVEABILITY AND EMISSIONS
I
LT BLUNVHT 441 IAC COIL "A" HI
SPARK
RETARD
TO
VSS BUFFER
TO
A/C HARNESS 4
INJ. 1,3,5,7 -
BACK VlEW OF
CONNECTOR
24 PIN A-B
CONNECTOR
BACK
VlEW OF
CONNECTOR
32 PIN C-D
CONNECTOR
2-27-87
Figure A-3 - Wiring Diagram - 5.OL (VIN F) & 5.7L (VIN 8) "F" Series (2 of 4)

DRIVEABILITY AND EMISSIONS 5.OL (VIN F) & 5.7L(VIN 8) 6E3-A-5
MAF SENSOR
POWER RELAY ECM
12v
FUEL
PUMP
RELAY DRIVE
(12W)
SYSTEM GND.
BACK VlEW
OF
CONNECTOR
FUEL PUMP
SIGNAL
24 PIN A-B
SYSTEM GND. CONNECTOR
BACK
VlEW OF
CONNECTOR
32 PIN C-D
CONNECTOR
SYSTEM GND.
ANALOG GROUND
MAF SIGNAL INPUT
BURN-OFF
CONTROL
Figure A-4 - Wiring Diagram - 5.OL (VIN F) & 5.7L (VIN 8) "F" Series (3 of 4)

BRAKE SWITCH
TANIBLK 456
DK GRNIY EL 428
TEMP.SWITCH
TANNVHT 250

DRIVEABILITY AND EMISSIONS 5.BL (VIN F) & 5.7L(VlN 8) 6E3-A-7
PORT FUEL INJECTION ECM CONNECTOR IDEN"II"IFICATI0IV
This ECM voltage chart is for use with a digital voltmeter to further aid in diagnosis. The voltages
you get may vary due to low battery charge or other reasons, but they should be very close.
B + in Chart refers to system voltage.
THE FOLLOWING CONDITIONS MUST
BE MET BEFORE TESTING:
@ Engine at operating temperature @ Engine idling in "Closed Loop" (for "Engine Run" column) in
park or neutral
e Test terminal not grounded @ "Scan" tool not installed
VOLTAGE
CONNECTOR
CONNECTOR
* Lessthan .5 volts.
1. Varies from .60 to battery voltage depending on position of drive wheels.
3. 12V First two seconds.
Figure
A-6 - ECM Connector Terminal End View - 5.OL (VIN F) & 5.7L (VIN 8) "F" Series