1988 PONTIAC FIERO ignition coil

6E3-C2-20 5.0L (VIN F) & 5.7L (WIN 8) DRIVEABILITY AND EMISSIONS
CONNECTOR - 441 BLUMlHT C5 IAC C0lL1'A" HI - 442 BLUIBLK C6 IAC COIL "A" LO - 443 GRNMlHT C4 IAC COIL "B" HI - 444 GRNIBLK C3 lAC COIL "B" LO v
START VALVE
CHART C-2C
IDLE AIR CONTROL (IAC) SYSTEM CHECK
S.OL (VIN F) & 5.7L (VIN 8) "F'" SERIES (PORT)
Circuit Description:
The ECM will control engine idle speed by moving the IAC valve to control air flow around the throttle
plates. It does this by sending voltage pulses to the proper motor winding for each IAC motor. This will cause
the motor shaft and valve to move
"IN" or "OUT" of the motor a given distance for each pulse received. ECM
pulses are referred to as "counts".
@ To increase idle speed - ECM will send enough counts to retract the IAC valve and allow more air to flow
through the idle air passage and bypass the throttle plates until idle speed reaches the proper rpm. This
will increase the ECM counts.
e To decrease idle speed - ECM will send enough counts to extend the IAC valve and reduce air flow through
the idle passage around the throttle plates. This will reduce the ECM counts.
Each time the engine is started and then the ignition is turned "OFF", the ECM will reset the IAC valve.
This is done by sending enough counts to seat the valve.
The fully seated valve is the ECM reference zero. A
given number of counts are then issued to open the valve, and normal ECM control of IAC will begin from this
point. The
number of counts are then calculated by the ECM. This is how the ECM knows what the motor
position is for a given idle speed.
The ECM uses the following information to control idle speed.
@ Battery voltage @ Engine speed @ Coolant temperature @ Throttle position sensor @ PIN switch e A/C clutch signal
Don't apply battery voltage across the IAC motor terminals. It will permanently damage the IAC motor
windin s. Test 6escription: Numbers below refer to circled
numbers on the diagnostic chart.
1. Continue with test, even if engine will not idle. If
idle is too low, "Scan" will display 80 or more
counts, or steps. If idle is high, it will display
"0"
counts.
Occasionally an erratic or unstable idle
[nay occur. Engine speed may vary 200 rpm or more up
and down. Disconnect IAC. If the condition is
unchanged, the IAC is not at fault.
There is a
system problem. Proceed to "Diagnostic Aids"
below.
2. When the engine was stopped, the IAC valve
retracted (more air) to
a fixed "Park" position for
increased air flow and idle speed during the next
engine start. A "Scan" will display 140 or more
coiints. 3. Be sure to disconnect the IAC valve prior to this
test.
The test light will confirm the ECM signals
by a steady or flashing light on all circuits.
4. There is a remote possibility that one of the
circuits is shorted to voltage which would have
been indicated by a steady light. Disconnect ECM
and turn the ignition "ON" and probe terminals to
check for this condition.
Diagnostic Aids:
Engine idle speed can be adversely affected by the
following:
@ ParMNeutral switch - If ECM thinks the car is
always in neutral, then idle will not be controlled
to the specified rpm when in drive range.
@ Leaking injector(s) will cause fuel imbalance and
poor idle quality due to excess fuel. See CHT.
A-7. @ Vacuum or crankcase leaks can affect idle. @ Whenthethrottleshaftorthrottlepositionsensor
is binding or sticking in an open throttle position,
the ECM does not know if the vehicle has stopped
and does not control idle.
@ Check A.I.R. management s stem for intermittent
air to orts while in "~losed~oo~". @ In ad&tion to electrical control of EGR, be sure to
examine the EGR valve for proper seating.
@ Faulty battery cables can result in voltage
variations. The ECM will try to compensate,
which results in erratic idle speeds.
@ 'I'he ECM will com ensate for A/C com ressor
clutch loacls. [.ass ofthe NC request sign8 would
he 11lost apparent, in neutral. @ Contalninatecl fuel can adverse1 affect idle. @ Perform i~!jector balance test C~ART C-2A. If ,111 OK, refer to "Rough, Unstable, Incorrect Idle or St ,tllinqW SJ tnptcfinsiin S~'ction "11''.

6E3-C4-4 5.OL (VIN F) & 5.7L (VIN 8) DRIVEABILITY AND EMISSIONS
"C" /
DISTRIBUTOR CONNECTOR
CONNECTOR
430 PPLNVHT
424 TANIBLK
- - - GRY. CONN.
2-F3-87
7-27-87
SS 1356-6E
CHART C-4
IGNITION SYSTEM CHECK
(INTEGRAL COIL)
5.0b (VIN F) & 5.7L (VIN 8) "F" SERIES (PORT)
Test Description: Numbers below refer to circled
numbers on the diagnostic chart.
1. Checks for proper output from the ignition system.
The spark tester requires a minimum of 25,000
volts to fire. This check can be used in case of an
ignition miss because the system may provide
enough voltage to run the engine but not enough
to fire a spark plug under heavy load.
IA. If spark occurs with EST connector disconnected,
pick-up coil output is too low for
EST operation.
2. Normal reading during cranking is about
8-10
volts.
3. Checks for a shorted module or grounded circuit
from the ignition coil to the module. The
distributor module should be turned
"OFF", so
normal voltage should be about 12 volts. If the
module is turned
"ON", the voltage would be low,
but above
1 volt. This could cause the ignition coil
to fail from excessive heat. With an open ignition
coil primary winding,
a small mount of voltage
will leak through the module from the battery to
the tach. terminal.
4. Checks the voltage output with the pick-up coil
triggering the module.
A spark indicates that the
ignition system has sufficient output, however,
intermittent no-starts or poor performance could
be the result of incorrect polarity between the
ignition coil and the pick-up coil
.
The color of the pick-up coil connector has to be
yellow, if one of the ignition coil leads is yellow. If
the ignition coil has a white lead, any pick-up coil
connector color, except yellow, is
OK.
5. Checks
for an open module or circuit to it. 12 volts
applied to the module
"P" terminal should turn
the module
"ON" and the voltage should drop to
about
7-9 volts.
6. This should turn "OFF" the module and cause a
spark. If no spark occurs, the fault is most likely
in the ignition coil, because most module problems
would have been found before this point in the
procedure.
A module tester could determine
which is at fault.

INDEX
SECTION PAGE
Cooling Fan Control
................. General Description C12-1
........................ Diagnosis C12-2
........................... Cuts Out B-5
................... Cylinder Select Error A-48
.................... Deceleration Mode C2-3
......................... Detonation B-4
..................... Dieseling. Run On B-6
............. Distributor Reference Signal C1-4
...................... ECM Terminals A-7
.................. ECM Wiring Diagram A3-A6
EGR Control Valve
................. General Description C7-1
................. Valve Identification C7-2
................... Diagnosis. Service C7-2
A-40
.................. EGR Control Solenoid C7-3
......................... EGR Check C7-4
Electronic Control Module
................. General Description C1-1
......................... Diagnosis C1-4
............................ Service C1-5
..................... Function Check C1-7
Electronic Spark Control (ESC) System
................. General Description C5-1
................... Diagnosis. Service C5-4
Electronic Spark Timing EST
............. A-50
A-52
Engine Cranks But Won't Run
............ A-14
........................ Engine Knock C5-4
.......................... ESC Module C5-2
.......................... ESC Sensor C5-1
.................... ESC System Check C5-4
................... ESTllgnition System C4-1
Evaporative Emission Control System
................. General Description C3-1
.......................... Diagnosis C3-2
Exhaust Emissions Excessive (Odors)
....... B-7
Exhaust Gas Recirculation (EGR) System
.... C7-1
Exhaust System Check Restricted
......... B-8
Fuel Control System
................. General Description C2- 1
......................... Diagnosis C2-5
..................... Fuel Cutoff Mode C2-3
SECTION PAGE
Fuel Injectors ........................
Fuel Pressure Connection Assy ............
Fuel Pressure Relief Procedure ...........
Fuel Pump Electrical Circuit .............
Fuel Pump Relay ......................
Fuel Rail
General Description
.................
........................... Service
Fuel System Diagnosis
..................
Fuel System Pressure Test ...............
Fuel Tank Pressure Control Valve .........
.......................... Hard Start B-2
.......... HE1 High Energy Ignition System C4-1
.......................... Hesitation
B-3
............ Idle Air Control System Check C2-20
.................. Idle Air
Control Valve C2-4
......................... Diagnosis C2-5
.................... Ignition System EST C4-1
........ Ignition System Check Integral Coil C4-4
........................ Incorrect Idle B-6
.................. Information Sensors C1.2. 9
.................. Injector
Balance Test C2-18
........................ lntermittents B-2
........................ Knock Sensor C1-3
........................ Lack Of Power B-4
......... Light. Manual Transmission Shift C8-6
.............. Light. Service Engine Soon A-10
MAF Sensor
.................. General Description C1-2
.......................... Diagnosis C1-5
A.42.44. 46
............................ Service C1-8
... Manual Transmission Electrical Diagnosis C8-10
MAT Sensor
.................. General Description C1-2
......................... Diagnosis C1-5
A.34. 38

6E-12 DRIVEABILITY AND EMISSIONS - FUEL INJECUION
and MPH) for abbreviations used in this Section, but
all types are acceptable.
NA/F - AI WFUEL (NF RATIO)
A.I.R.
- AIR INJECTOR REACTION SYSTEM - Air
flow from pump is directed into engine exhaust
manifold
and/or converter to reduce exhaust
emissions.
ALDL - ASSEMBLY LINE DIAGNOSTIC LINK - Used
at assembly to evaluate Computer Command Control,
and for service to flash the "Service Engine Soon"
light
if there are trouble codes. It also is used by
"Scan" tools to obtain ECM serial data.
BARO - BAROMETRIC ABSOLUTE PRESSURE
SENSOR
- Reads atmospheric pressure.
B + - Battery Positive Terminal (12 Volts) or
system voltage with the engine running
(approximately 13.8
v.)
CALPAK - A device used with fuel injection to
allow fuel delivery in the event of a PROM or ECM
malfunction.
CALIBRATOR - (PROM) - An electronic component
that can be
specifically programmed to meet engine
operating requirements for a
specific vehicle model.
It plugs into the Engine Control Module
(ECM).
CCC - COMPUTER COMMAND CONTROL - has an
electronic control module to control airlfuel and
emission systems.
CLCC - CLOSED LOOP CARBURETOR CONTROL -
Used to describe oxygen sensor to ECM to MIC
solenoid circuit operation.
C3I - Computer Controlled Coil Ignition. Produces
the ignition spark without the aid of an ignition
distributor.
CCP - CONTROLLED CANISTER PURGE - ECM
controlled solenoid valve that permits manifold
vacuum to purge the evaporative emissions from the
charcoal canister.
CID - CUBIC INCH DISPLACEMENT - Used to
describe engine size.
UL OR ULOOP - "CLOSED LOOP" - Describes ECM
fuel control when using oxygen sensor information.
COOLANT TEMPERATURE SENSOR - Device that
senses the engine coolant temperature, and passes
that information to the engine control module.
CONV. - CATALYTIC CONVERTER, THREE-WAY -
EXHAUST CONVERTER. Containing platinum and
palladium to speed up conversion of
HC and CO, and
rhodium to accelerate conversion of NO,.
CO - CARBON MONOXIDE - One of the pollutants
found in engine exhaust.
6V - CRANKCASE VENTlhaflON - Prevents fumes
in crankcase from passing into the atmosphere, by
drawing them into the intake manifold and burning
them in the the combustion process.
DIAGNOSTIC CODE - Pair of numbers obtained
from flashing "Service Engine Soon" light or
displaying on a "Scan" tool. This code can be used to
determine the system malfunction.
DIAGNOSTIC TERM. - Lead of ALDL Connector
which is grounded to get a Trouble Code.
It is
grounded with the engine running to enter the "Field
Service Mode".
DIS - Direct Ignition System. Produces the
ignition spark without the aid of an ignition
distributor.
DVM (10 Meg.) - Digital Voltmeter with 10 Million
ohms resistance
- used for measurement in electronic
systems.
DWELL - The amount of time (recorded on a dwell
meter in degrees of crankshaft rotation) that current
passes through a closed switch; for example, ignition
contact points or internal switch in an electronic
control module.
EAC - ELECTRIC AIR CONTROL - Used on A.I.R.
system to direct air flow to air switching valve or to
atmosphere.
EAS - ELECTRIC AIR SWITCHING - used to direct air
flow to catalytic converter or exhaust ports of the
engine.
ECM - ENGINE CONTROL MODULE (ELECTRONIC) -
A metal case (located in passenger compartment)
containing electronic circuitry which electrically
controls and monitors airlfuel and emission systems
on computer command control, and turns
"ON" the
"Service Engine Soon" light when a malfunction
occurs in the system.
EFI - ELECTRONIC FUEL INJECTION - Computer
Command Control using throttle body fuel injection.
EGR - EXHAUST GAP REClRCUbATlON - Method of
reducing NO, emission levels by causing exhaust gas
to be added to airlfuel mixture in combustion
chamber, thus cooling combustion.
EECS - EVAPORATIVE EMISSIONS CONTROL
SYSTEM
- Used to prevent gasoline vapors in the fuel
tank from entering the atmosphere.
EFE - EARLY FUEL EVAPORATION - Method of
warming the intake manifold during cold engine
operation. Provides efficient airlfuel mixing.
ENERGIZEIDE-ENERGIZE - When current is passed
through a coil (energized) such as the canister purge
solenoid, the plunger is pulled into the solenoid.

DRIVEABILIW AND EMISSIONS - FUEL INJECTION 6E-13
When the voltage to the solenoid is turned off, (de-
energized), a spring raises the plunger.
ESC - ELECTRONIC SPARK CONTROL - Used to
sense detonation and retard spark advance when
detonation occurs.
EST - ELECTRONIC SPARK TIMING - ECM
controlled timing of ignition spark.
EVRV - ELECTRONIC VACUUM REGULAWR
VALVE - Controls EGR vacuum.
FED - FEDEWL - VehicleIEngine available in all
states except California.
GROUND - The negative (-) side of the battery.
Also could be a wire (conductor) shorted to ground.
HC - HYDROCARBONS - One of the pollutants
found in engine exhaust.
HIGH IMPEDANCE VOLTMETER - Mas high
opposition to the flow of electrical current.
Good for
reading circuits with low current flow, such as found
in electronic systems because it allows tests to be
made without affecting the circuit.
HE1 - HIGH ENERGY IGNITION - A distributor that
uses an electronic module and pick-up coil in place of
contact points.
Hg - MERCURY - A calibration material used as a
standard for vacuum measurement.
IAC - IDLE AIR CONTROL - A valve installed in the
throttle body of fuel injected systems and controlled by
the ECM to regulate idle speed.
IDEAL MIXWRE - The airlfuel ratio which provides
the best performance, while maintaining maximum
conversion of exhaust emissions. Typically it is
14.7:1.
ID1 - INTEGRATED DIRECT IGNITION - Produces the
ignition spark without the aid of an ignition
distributor or spark plug wires.
IDLE AIR BLEED VALVE - Controls the amount of
air let into the idle fuel mixture prior to the mixture
entering the carburetor idle system, when the
MIC
solenoid is energized.
ILC - IDLE LOAD COMPENSATOR - Device used to
control throttle angle during long deceleration, such
as coasting down a long grade; it extends at wide open
throttle position or to prevent engine stalls at idle.
INPUTS - Information from sources (such as
coolant temperature sensors, exhaust oxygen sensor,
etc.) to the ECM that indicate how the systems are
performing.
INTERMITTENT - Occurs now and then; not
continuously. In electrical circuits, refers to
occasional open, short, or ground.
I.P. - INSTRUMENT PANEL
ISC - IDLE SPEED CONTROL - Regulates throttle
valve position to control idle speed. Idle speed is
controlled by the ECM and is not adjustable.
KMIHR - KILOMEnR PER HOUR - A metric unit
measuring speed needed to travel distance of one
kilometer (1000 meters) in one hour.
L - LITER - A metric unit of capacity.
L4 - FOUR CYLINDER IN-LINE ENGINE
MAF - MASS AIR FLOW - Sensor which measures
the amount of air entering the engine.
MALFUNCTION - A problem that causes the
system to operate incorrectly. Typical malfunctions
are wiring harness opens or shorts, failed sensors or
circuit components.
MANIFOLD VACUUM SENSOR - Indicates vacuum
in the intake manifold by measuring the pressure in
intake manifold in relation to barometric pressure. It
is also called a differential pressure sensor because
it
measures the difference between the two pressures. It
puts out a voltage which is highest when the vacuum
is highest. The maximum voltage is between 4 and 5
volts.
MAP - MANIFOLD ABSOLUTE PRESSURE SENSOR -
Reads pressure changes in intake manifold with
reference to zero pressure. It puts out a voltage which
is highest when the pressure is highest. The
maximum voltage is between
4 and 5 volts.
MAT - Manifold Air Temperature Sensor.
Measures temperature of air in the intake manifold.
MIC - MIXTURE CONTROL
MEM-CAL
- MEMORY CALIBRATOR - Contains
specific calibrations to meet the requirements of a
specific engine.
MFI - MULTlPORT FUEL INJECnON - Individual
injectors for each cylinder are mounted in the intake
manifold. The injectors are fired in groups rather than
individually.
MIXTURE CONTROL (MIC) SOLENOID - Device,
installed in carburetor, to regulate the airlfuel ratio.
MODE - A particular state of operation.
MPH - MILES PER HOUR - A unit measuring speed
needed to travel distance of one mile (5280 feet) in one
hour.
N.C. - NORMALLY CLOSED - State of relay contacts
or solenoid plunger when no voltage is applied.
N-rn - NEWTON METER (Torque) - A metric unit
describing force.

SYMBOLS
CIRCUIT BREAKER
SWITCH CONTACTS THAT
MOVE TOGETHER
DASHED LlNE SHOWS
A MECHANICAL
CONNECTION BETWEEN SWITCH
CONTACTS
~26 IN THE SAME
CONNECTOR
DASHED
LlNE SHOWS
A PHYSICAL
CONNECTION BETWEEN PARTS
(SAME
CONNECTORl
ELECTRONIC
CONTROL
MODULE
(ECM) SOLlO STATE
STATE1 .,, ,,,--=----,-a
"SOLIO STATE" IDENTIFIES
MODULE AS ELECTRONIC.
SIMPLIFIED COMPONENTS
WITHIN THE MOOULE
SHOW HOW EACH CIRCUIT
IS COMPLETED. DO NOT
MEASURE RESISTANCE
OF CIRCUITS
INSIDE SOLlO STATE MODULES. HEAT
HEATING
ACTUATED ELEMENT CONTACT
RELAY SHOWN
WlTH NO
CURRENT FLOWING
THROUGH
COIL
NORMALLY
WHEN CURRENT FLOWS CLOSE0
THROUGH COIL, CONTACT CONTACT
MOVES TO NORMALLY OPEN POSITION
NORMALLY
OPEN
CONTACT
FUSIBLE
LINK
I I
SCREW TERMINAL,
SHOWN SEPARATED
I BAAKE I INDICATOR I AN INDICATOR (RED, ! WHICH DISPLAYS
3 BLK
INDICATES THAT
THE CIRCUITRY IS
NOT SHOWN IN
COMPLETE DETAIL
BUT
IS COMPLETE IN
150 THE INOICATED CELL
SEE GROUND OlSTRlBUTlON
GZOO . -
WlRE CHOICES
FOR OPTIONS
GAGES OR DIFFERENT
SHOWN
AN0 LABELED
COLOR OF
- FUSE BLOCK - - - - - - - . . CONNECTOR
INOICAT / POWER IS SUPPLIED I $ I / WlTH IGNITION SWITCH IN ACCY /' AN0 RUN POSITIONS
LABEL OF FUSE
BLOCK CONNECTOR
CAVITY
DIODE CURRENT CAN
FLOW ONLY IN
N- THE DIRECTION
OF THE ARROW
3 CONNECTORS ARE
SHOWN CONNECTED
TOGETHER AT A
JUNCTION BLOCK.
FOURTH
WIRE IS
SOLDERED TO COMMON
CONNECTION ON BLOCK.
CONNECTOR NUMBER
LETTERS FOR EACH
CAVITY

POWER DISTRIBUTION
COMPONENT LOCATlON Page-Figure
Fusible Link A (VIN S)
............ Lower RH side of engine. at Starter Solenoid ....
Fusible Link B (VIN E) ............ Lower RH side of engine. at Starter Solenoid ....
Fusible Link B (VIN F) (VIN 8) ..... Lower RH side of engine. at Starter Solenoid ....
............ Fusible Link B (VIN S) Lower
RH side of engine. at Starter Solenoid ....
Fusible Link D .................. Front lights harness. near LH side of dash ......
Fusible Link E ................... Front lights harness. near LH side of dash ......
Fusible Link G .................. Front lights harness. near LH side of dash ......
Fusible Link H (VIN E) ........... RH front of engine compartment. at Junction
Block
...................................
Fusible Link N (VIN F) (VIN 8) ..... LN front of engine compartment. behind battery
Fusible Link H (VIN S)
............ Lower RH side of engine. at Starter Solenoid ....
J (VIN E) ............ Lower RH side of engine, at Starter Solenoid ....
J (VIN F) (VIN 8) ..... Lower RH side of engine, at Starter Solenoid ....
J (VIN S) ............ RH side of radiator support. at Junction Block ..
.................. Fusible Link K RN front of engine compartment. at Junction
Block
...................................
Gear Selector Switch ............. In console, at base of gear selector ............
Hatch Fuse ..................... Attached to side of Fuse Block
Hatch Pull-Down Unit
............ Center of end panel, in cargo compartment .....
Headlight Door Module ........... LH front of dash ...........................
Ignition Coil (VIN S) .............. Rear RH side of engine ......................
Ignition Switch .................. Behind IIP. on top side of steering column ......
In-Line Fuse (VIN F)(VIN 8) ....... On LH side of radiator support. forward of
................................. battery
.................. Junction Block RH front of engine compartment. behind
................................ headlight
Lights Monitoring Module
......... Behind IIP. at base of steering column
Mass Air Flow (MAF) Relay (VIN
F)
........................ (VIN 8) LH rear corner of engine compartment, on relay
................................. bracket
Mass Air Flow (MAF) Relay (VIN S)
. Front of engine compartment. on RH side of
radiator bracket
..........................
Mass Air Flow In-Line Fuse ........ RN side of engine compartment, on inner fender
panel
...................................
Remote Dimmer ................. RH side of steering column. on IIP retainer .....
Starter Solenoid (VIN E) .......... Lower RH side of engine ....................
Starter Solenoid (VIN F) (VIN 8) .... Lower RH side of engine ....................

MULTI-PORT FUEL INJECTION: V6 VIN S
COMPONENT LOCATION
AIC Compressor Control Relay ..... LH rear corner of engine compartment, on relay
................................. bracket
AIR Select Valve (VIN S)
.......... Lower RN side of engine, behind AIR pump
Assembly Line Diagnostic Link
(ALDL) Connector
.............. On bottom of IIP hush panel, to right of steering
column
Brake Switch.
................... Above brake pedal, on brake pedal support .....
Canister Purge Solenoid Valve (VIN
............................ .. S) Lower RH front
corner of engine compartment
Cold Start Injector (VIN S)
........ Top LH rear of engine ......................
Cold Start Switch (VIN S) ......... Top of engine
Coolant Temperature Sensor (VIN S) Top LN front of intake manifold.
.............
Electronic Control Module (ECM) ... Behind RH side of IIP ......................
Electronic Spark Timing (EST)
......................... Distributor (VIN S) ............. Top rear of engine.
Electronic Vacuum Regulator Valve
(EVRV)
....................... TopRHrearofengine ......................
Fan Pressure Switch (VIN S) ....... Lower RH front of engine compartment, on AIC
line ....................................
Fuel Injectors ................... Top of engine, at each intake cylinder
Fuel Pump In-Line Fuse.
.......... RH side of engine compartment, on inner fender
panel
...................................
Fuel Pump Relay (VIN S) .......... LH rear corner of engine compartment, on relay
................................. bracket
Fuel Pump Switch (VIN S)
......... Lower LH side of engine ....................
Fuel Tank Unit .................. Top center of fuel tank ......................
Fuse Block. ..................... Behind LH side of IIP, below light switch. ......
Gear Selector Switch ............. In console, at base of gear selector ............
Idle Air Control Stepper Motor (VIN
S)
............................ Topcenterofengine ........................
Ignition Coil (VIN S). ............. Rear RH side of engine. .....................
Ignition Switch. ................. Behind IIP, on top side of steering column ......
Manifold Air Temperature (MAT)
................. Sensor (VIN S) RH front of engine compartment, on air cleaner
............................... assembly. Page-Figure