1988 PONTIAC FIERO spark plugs replace

DWI\/EABILITV AND EMISSIONS 2.8L (VIN 5) 6E3-B-5
CU"T SUP, MISSES
Definition: Steady pulsation or jerking that follows engine
speed, usually more pronounced as engine load increases. The
exhaust has a steady spitting sound at idle or low speed.
@ Perform careful visual check as described at
start of Section
"B".
@ Check for missing cylinder by:
1. Disconnect IAC valve. Start engine.
Remove one spark plug wire at a time
using insulated pliers.
2. If there is an rpm drop on all cylinders
(equal to within
50 rpm), go to "ROUGH,
UNSTABLE, OR INCORRECT IDLE,
STALLING" symptom. Reconnect IAC
valve.
3. If
there is no rprn drop on one or more
cylinders, or excessive variation in drop,
check for spark on the suspected
cylinder(s) with J 26792 (ST-125) Spark
Gap Tool or equivalent.
If no spark, see
Section
"6D" for intermittent operation or
miss. If there is spark, remove spark
plug(s) in these cylinders and check for:
- Cracks
- Wear
- Improper gap
- Burned electrodes
- Iieavy deposits
@ Perform compression check on questionable
cylinder(s) found above. If compression is low,
repair as necessary. See Section
"6".
@ Disconnect all injector harness connectors.
Connect
5-34730-2 injector test light or
equivalent 6 volt test light between the
harness terms, of each injector connector and
note light while cranking. If test light fails to blink
at any connector, it is a faulty injector drive
circuit harness, connector, or terminal.
@ Perform the injector balance test. See CHART C-
2A.
s CHECK:
- Spark plug wires by connecting ohmmeter to
ends of each wire in question. If meter reads over
30,000 ohms, replace wire(s1.
- Fuel System - Plugged fuel filter, water, low
pressure. See
CHART A-7.
- Valve timing.
- Secondary voltage using a shop ocilliscope or a
spark tester 5-26792 (ST-125) or equivalent.
@ Visually inspect distributor cap and rotor for
moisture, dust, cracks, burns, etc. Spray cap and
plug wires with, fine water mist to check for
shorts.
@ A miss condition can be caused by EM1
(Electromagnetic Interference) on the reference
circuit.
EM1 can usually be detected by
monitoring engine rpm with a "Scan" tool. A
sudden increase in rpm with little change in
actual engine rpm change, indicates
EM1 is
present. If the problem exists, check routing of secondary
wires, check all distributor ground circuits.
@ Remove rocker covers. Check for bent pushrods,
worn rocker arms, broken valve springs, worn
camshaft lobes. Repair as necessary. See Section
"6A".
BACKFIRE
Definition: Fuel ignites in intake manifold, or
in exhaust system, making a loud popping noise.
CHECK:
- Loose wiring connector or air duct at MAF
sensor.
- Compression - Look for sticking or leaking
valves.
- EGR operation for being open all the time. See
CHART C-7.
- EGR gasket for faulty or loose fit .
- Valve timing.
- Output voltage of ignition coil using a shop
ocilliscope or spark tester 5-26792 (ST-125) or
equivalent.
- Spark plugs for crossfire also inspect (distributor
cap, spark plug wires, and proper routing of plug
wires).
- Ignition system for intermittent condition. (See
Section
"6D").
- Engine timing - see Emission Control
Information label.
- Perform fuel system diagnosis check, CIIART A-
7A.
- Perform injector balance test, CHART C-2A.
- Deceleration valve (2.8L ~nanualltrans) - See
Section
"C6".
- A.I.R. system check valves - See Section "C-6".

6E3-A-14 5.0L (VIN F) & 5.7L (VIN 8) DRIVEABILITY AND EMISSIONS
CHART A-3
(Page 1 of 2)
ENGINE CRANKS BUT WON'T RUN
5.OL (VIN F) & 5.7L (VIN 8) "F" SRIES (PORT)
Circuit Description :
This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in
the tank.
Test Description: Numbers below refer to circled Diagnostic Aids:
numbers on the diagnostic chart.
1. A "Service Engine Soon" light "ON" is a basic test @ An EGR valve sticking open can cause a low
to determine if there is a
12 volt supply and airlfuel ratio during cranking. Unless
engine
ignition
12 volts to ECM. No ALDL may be due to enters
"Clear Flood" at the first indication of a
an ECM problem and CHART
A-2 will diagnose flooding
condition, it can result in a no start.
the ECM. If TPS is over
2.5 volts the engine may @ Check for fouled plugs.
be in the clear flood mode which will cause
@ A defective cold start circuit or water in fuel line
starting problems. The engine
will not start can
cause a no start in cold weather. See
CHART
without reference pulses and therefore the "Scan" A-9.
should read rpm (reference) during crank. @ A defective MAF Sensor may cause a no start or a
2. No spark may be caused by one of several stall
after start. To determine if the sensor is
components related to the Ignition System. causing
the problem, disconnect it. The
ECM will
CHART C-4 will address all problems related to then
use a default value for the sensor, and if the
the causes of a no spark condition. condition
is corrected and the connections are
OK,
3. The test light should blink, indicating the ECM is replace the sensor.
controlling the injectors ok. How bright the light
@ rllso check that injectors on both sides of engine
blinks is not important. However, the test light
will cause a test light to "blink". If not OK, check
should be a
5-34730-3 or equivalent. injector fuses.
4. Use fuel
pressure gage 5-34730-1 or equivalent. If al~ove are all OK, refer to "Symptoms" it1
Wrap a shop towel around the fuel pressure tap to Scction "R". Ilard Start.
absorb any small amount of fuel leakage that may
occur when installing the gage.

6E3-B-2 5.OL (VIN F) & 5.7L (VIN 8) DRIVEABILITY AND EMISSIONS
Problem may or may not turn "ON" the "Service Engine Soon" light, or store a code.
DO NOT use the Trouble Code Charts in
An intermittent "Service Engine Soon" light
Section A for intermittent problems. The fault must
with no stored code may be caused by:
be present to locate the problem. If a fault is
@ Ignition coil shorted to ground and arcing at
intermittent, use of Trouble Code Charts
may result
spark plug wires or plugs.
in replacement of good parts.
"Service Engine Soon" light wire to
ECM
@ Most intermittent problems are caused by
shorted to ground. (CKT 419).
faulty electrical connections or wiring. Perform
Diagnostic "Test" Terminal wire to ECM,
careful check as described at start of Section
shorted to
ground.(CKT 451)
"B". Check for:
@ ECM power grounds. See ECSI wiring
@ Poor mating of the connector halves, or diagrams.
terminals not fully seated in the connector
@ Loss of trouble code memory. To check,
body (backed out). disconnect TPS and idle engine until "Service
@ Improperly formed or damaged terminals.
Engine Soon" light comes on. Code 22 should be
All connector terminals in problem circuit
stored, and kept in memory when ignition is
should be carefully reformed or replaced to turned "OFF". If not, the ECM is faulty.
insure proper contact tension.
@ Check for an electrical system interference
@ Poor terminal to wire connection. This caused by a defective relay, ECM driven
requires removing the terminal from the
solenoid, or switch. They can cause a sharp
connector body to check. See "Introduction"
electrical surge. Normally, the problem will
to Section
"6E". occur when the faulty component is operated.
@ If a visual check does not find the cause of the @ Check for improper installation of electrical
problem, the car can be driven with a voltmeter
options, such as lights,
%way radios, etc.
connected to
a suspected circuit. A "Scan" tool
EST wires should be kept away from spark plug
can also be used for monitoring input signals to wires, distributor wires, distributor housing,
the ECM to help detect intermittent conditions. coil, and generator. Wire from
ECM to
An abnormal voltage, or "Scan" reading, when distributor
(CKT 453) should be a good
the problem occurs, indicates the problem
may connection.
be in that circuit. If the wiring and connectors
@ Check for open diode across AIC compressor
check OK and a Trouble Code was stored for a
clutch, and for other open diodes (see wiring
circuit having a sensor, except for Codes
43, 44, diagrams).
and 45, substitute a known good sensor and
recheck.
HARD START
Definition: Engine cranks OK, but does not start for a long
time. Does eventually run, or may start but immediately dies.
Perform careful check as described at start of
Section
"B".
@ Make sure driver is using correct starting
procedure.
@ CHECK:
- TPS for sticking or binding or a high TPS
voltage with the throttle closed (should read
less than
.700 volts).
- High resistance in coolant sensor circuit or
sensor itself. See Code 15 chart or with
a
"Scan" tool compare coolant temperature with
ambient temperature on a cold engine.
- Fuel pressure CHART A-7.
- Water contaminated fuel.
- EGR operation. Be sure valve seats properly and
is not staying open. See CHART C-7.
- Both injector fuses (visually inspect).
- Ignition system - Check distributor for:
Proper Output with ST-125.
Worn shaft.
Bare and shorted wires.
Pickup coil resistance and connections.
Loose ignition coil ground.
Moisture in distributor cap.
@ If problem exists in cold weather, check cold start
valve. See CHART A-9.

DRIVEABILITY AND EMISSIONS 5.OL (VIN F) & 5.7L (VIN 8) 6E3-8-3
@ A faulty in-tank fuel pump check valve will @
allow the fuel in the lines to drain back to the
tank after the engine is stopped. To check for
this condition:
e
Perform Fuel System Diagnosis, CHART A-7.
@ Remove spark plugs. Check for wet plugs,
cracks, wear, improper gap, burned electrodes,
@
or heavy deposits. Repair or replace as
necessary. If
engine starts but then immediately stalls
open distributor by-pass line. If engine then
starts and runs OK, replace pickup coil.
If engine starts and stalls disconnect MAF
sensor. If engine then
r~lns and sensor
connections are OK, replace
thr. )t.ft+rl'.
Basic engine problem.
HESITATION, SAG, STUMBLE
Definition: Momentary lack of response as the accelerator i., pl,ihcc! dowt-
Can occur at all car speeds. Usually most severe when first tryine, lo m,tlir. LII~.
car move, as from a stop sign. May cause the engine to sta!! 1, e er., riu~~~!~
s Perform careful visual check as described at
start of Section
"B".
@ CHECK:
- Fuel pressure. See CHART A-7. Also, check
for water contaminated fuel.
- Air leaks at air duct between MAF sensor and
throttle body.
- Spark plugs for being fouled or faulty wiring.
- Mem-Cal number. Also check service bulletins
for latest Mem-Cal.
- TPS for binding or sticking. Voltage should
increase at
a steady rate as throttle is moved
toward WOT.
- Ignition timing. See emission control
information label.
- Generator output voltage. Repair if less than 9
or more than 16 volts.
- HE1 ground, CKT 453.
- Canister purge system for proper operation.
See CHART C-3.
- EGR - See CHART C-7.
e Perform injector balance test CHART C-2A.
SURGES AND/OR CHUGGLE
Definition: Engine power variation under steady
throttle or cruise. Feels like the car speeds up and
slows down with no change in the accelerator pedal.
@ Be sure driver understands transmission
converter clutch and
AJC compressor operation
in owner's manual.
Perform careful visual inspection as described
at start of Section
"B".
e CHECK:
- Loose or leaking air duct between MAF sensor
and throttle body.
- Generator output voltage. Repair if less than 9
or more than 16 volts.
- EGR - There should be no EGR at idle. See
CHART C-7.
- Vacuum lines for kinks or leaks.
- Ignition timing. See emission control
information label.
- In-line fuel filter. Replace if dirty or plugged.
- Fuel pressure while condition exists. See
CHART A-7.
@ Inspect oxygen sensor for silicon contamination
from fuel, or use of improper RTV sealant. The
sensor may have a white, powdery coating and
result in a high but false signal voltage (rich
exhaust indication). The ECM will then reduce
the amount of fuel delivered to the engine,
causing a severe driveability problem.
@ Remove spark plugs. Check for cracks, wear,
improper gap, burned electrodes, or heavy
deposits. Also check condition of distributor
cap, rotor, and spark plug wires.
@ To help determine if the condition is caused by a
rich or lean system, the car should be driven at
the speed of the complaint. Monitoring block
learn at the complaint speed will help identify
the cause of the problem.
If the system is lean
(block learn greater than
1381, refer to
"Diagnostic Aids"
on facing page of Code 44. If
the system is running rich (block learn less than
1181, refer to "Diagnostic Aids" on facing page
of Code
45.

DRIVEABILITY AND EMISSIONS S.OL (VIN F) & 5.7L (VIN 8) 6E3-B-5
Definition: Steady pulsation or jerking that follows engine
speed, usually more pronounced as engine load increases. The
exhaust has
a steady spitting sound at idle or low speed.
@ Perform careful visual check as described at blink
at any connector, it is a faulty injector drive
start of Section
"B". circuit harness, connector, or terminal.
@ Check for missing cylinder by: @ Perform the Injector Balance Test. See CHART
1. Disconnect IAC valve. Start engine. C-2A.
Remove one spark plug wire at a time
@ CHECK:
using insulated pliers. - Spark plug wires by connecting ohmmeter to
2. If there is an rpm drop on all cylinders ends
of each wire in question. If meter reads over
(equal to within
50 rpm), go to "ROUGH, 30,000
ohms, replace wire(s).
UNSTABLE, OR INCORRECT IDLE, - Fuel System - Plugged fuel filter, water, low
STALLING" symptom. Reconnect IAC pressure. See CHART A-7.
valve.
- Valve timing.
3. If there is no rpm drop on one or more - Secondary voltage using a shop ocilliscope or a
cylinders, or excessive variation in drop, spark tester 5-26792 (ST-125)
or equivalent.
check for spark on the suspected
@ Visually inspect distributor cap and rotor for
cylinder(s) with J 26792 (ST-125) Spark moisture, dust, cracks, burns, etc. Spray cap and
Gap Tool or equivalent. If no spark, see plug wires with fine water mist to check for
Section 6D for Intermittent Operation or shorts.
Miss. If there is spark, remove spark
@ A miss condition can be caused by EM1
plug(s) in these cylinders and check for: (Electromagnetic Interference) on the reference
- Cracks circuit. EM1 can usually be detected by
- Wear monitoring engine rpm with a "Scan" tool. A
- Improper Gap sudden
increase in rpm with little change in
- Burned Electrodes actual engine rpm change, indicates EM1 is
- Heavy Deposits present.
@ Perform compression check on questionable If
the problem exists, check routing of secondary
cylinder(s) found above. If compression is low, wires, check
all distributor ground circuits.
repair as necessary. See Section
"6". @ Remove rocker covers. Check for bent pushrods,
@ Disconnect all injector harness connectors. worn
rocker arms, broken valve springs, worn
Connect
5-34730-2 Injector Test Light or camshaft
lobes. Repair as necessary. See Section
equivalent 6 volt test light between the
"6A".
harness terms, of each injector connector and
note light while cranking. If test light fails to
BACKFIRE
Definition: Fuel ignites in intake manifold, or
in exhaust system, making a loud popping noise.
@ CHECK: - Spark plugs for crossfire also inspect (distributor
- Loose wiring connector or air duct at MAF
cap, spark plug wires, and proper routing of plug
sensor. wires).
- Compression - Look for sticking or leaking - Ignition system for intermittent condition. (See
valves. Section
"6D").
- EGR operation for being open all the time. See - Engine timing - see emission control information
CHART C-7. label.
- EGR gasket for faulty or loose fit. - Perform fuel system diagnosis check, CHART A-
- Valve timing. 7A.
- Output voltage of ignition coil using a shop - Perform injector balance test CI-IART C-2A.
ocilliscope or spark tester 5-26792 (ST-125) or
- A.I.R. system check valves - See Section "C-6".
equivalent.

RADIO SYSTEMS AND ANTENNAS 9A-1
SECTION 9A
0 SYSTEMS AND ANTENNAS
CONTENTS
............................................. General Description .................................... 9A-1 Radio Operation 9A-4
Radio
............................................................ 9A-1 ETR AM/FM Stereo (UM-7) ....................... 9A-4
Antennas
........................................................ 9A- 1 ETR Stereo Cassette (UM-6) ......................... 9A-5
Fixed Antenna
.......................................... 9A- 1 ETR Stereo/Cassette/Eaualizer
Diagnosis ........................................................
Radio ....................... .. ................................
Static and Noise .................................... .....
........................................ Popping Noise
Preliminary Diagnostics
.............................
Antenna ................................. .. ................
Tape Player .................. .... .......................
Service Procedures ....................................
Radio and Speakers ........................... .............
Radio Noise Suppression Equipment ............
Stereo Cassette Tape Player ..........................
Tape & Tape Player Care ........................
(UX-1) ..................................................... 9A-6
Advanced ETR
Stereo/Cassette/Equalizer Touch
Control
.................................... ... .............. 9A-7
On-Car Service .............................................. 9A-9
Radio Receiver
............................................ 9A-9
Radio Steering Wheel Controls
..................... 9A-9
Audio Amplifier
........................................... 9A-9
Radio Suppression
..................................... 9A-9
Front Speaker
................................................. 9A-9
............... Rear Speaker; Sub Woofer Speaker
9A-9
Antenna
..................... .. ............................. 9A- 10
GENERAL DESCRIPUION
RADIO ANTENNAS
For radios and radio use see the "Radio Fixed Antenna
Operation" section. ETR means 'Electronically Tuned The
fixed antenna on the right front fender
Receiver'. cannot be adjusted up or down. It may provide
improved reception in rural areas.
- The fixed antenna is designed to withstand most
car washes without damage. If the antenna becomes
slightly bent, you can straighten it by hand. The
antenna can be replaced if severely bent (by vandalism,
etc.). Antennas must be kept clean for good
performance.
RADIO
Because radio problems are normally repaired at
authorized warranty repair stations, the tendency is to
remove the set when a problem is reported, without any
preliminary diagnosis. This results in a large number
of radios being "No Trouble Found" units when
received by the warranty repair stations. Often the
trouble can be corrected without radio removal. wire.
If equipped with
A/C, the blower motor has a
built-in capacitor. Extra electrical equipment added to
the static if not properly grounded or wiring was
improperly routed.
Weak
FM station reception will be affected by
nearby buildings, car speed and direction. These
"flutter" and "fading" conditions are characteristic of
weak FM signals.
ETR radios require clock and button reset if the
battery is disconnected.
Popping Noise
Static and Noise Operating devices such as turn signals, pushing in
cigarette lighter, operating stop lights, etc., may cause
Ground strap connections must be clean and
a popping noise on distant (weak) AM signals.
tight, spark plug cables must be TVRS type and in
good condition and resistance-type spark plugs used.
Preliminary Diagnostics
Capacitors are used in the generator, heating/air
conditioning system, and fuse panel to reduce noise
The inconvenience of driving without a radio
entering the radio through the feed wires. If the car has
while the set is being serviced can often be avoided if
a heater only, the capacitor is in the blower motor feed
the following quick checks are used to eliminate