1988 PONTIAC FIERO oil filter

DRIVEABILITY AND EMISSIONS - 5.OL (\/IN El 6EZ-CZ-5
sent to the ECM. The ECM then increases the injector
base pulse width, permitting increased fuel flow.
As the throttle valve rotates in response to
movement of the accelerator pedal, the throttle shaft
transfers this rotational movement to the
'I'PS. A
potentiometer (variable resistor) within the TPS
assembly changes its resistance (and voltage drop) in
proportion to throttle movement.
By applying a reference voltage (5.0 volts) to the
TPS input, a varying voltage (reflecting throttle
position) is available at the TPS output. For example,
approximately 2.5 volts results from a 50% throttle
valve opening (depending on TPS calibration). The
voltage output from the TPS assembly is routed to the
ECM for use in determining throttle position.
FUEL PUMP
The fuel pump is a turbine type, low pressure
electric pump, mounted in the fuel tank. Fuel
is
pumped at a positive pressure (above 62
kPa or 9 psi)
from the fuel pump through the in-line filter to the
pressure regulator in the TBI assembly Excess
fuel is
returned to the fuel tank through the fuel return line.
The fuel pump is attached to the fuel gage sender
assembly. A fuel strainer is attached to the fuel pump
inlet line and prevents dirt particles from entering the
fuel line and tends to separate
water from the fuel
Vapor lock problems are reduced when using an
electric
pump because the fuel is pushed from the tank
under pressure rather than being pulled
under
vacuum, a condition that produces vapor.
An inoperative fuel pump would cause
a. no start
condition. A fuel pump which does not provide enough
pressure can result in poor performance. (See "Fuel
System Pressure Test" procedure).
FUEL PUMP ELECTRICAL CIRCUIT
When the key is first turned "ON" without the
engine running, the ECM turns 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 shuts the fuel pump "OFF" and
waits until the engine starts. As soon as the engine is
cranked, the ECM turns the relay
"ON" and runs the
fuel pump.
As a backup system to the fuel pump relay, the
fuel pump can also be turned on
by the oil pressure
switch. The oil pressure sender has two circuits
internally. One operates the oil pressure indicator or
gage in the instrument cluster,
itnd the other is
anormally open switch which closes when oil pressure
reaches about 28
kPa (4 psi). If the fuel pump relay
fails, the oil pressure switch will run the fuel pump. An
inoperative fuel pump relay can result in long
cranking times, particularly if the engine is cold. The
oil pressure switch will turn on the fuel pump as soon
as oil pressure
reaches about 28 kPa (4 psi).
FUEL CONTROL
Always start with the "Diagnostic Circuit Check"
in Section
"6E2-A". This will reduce diagnosis time
and prevents unnecessary replacement of parts. The
information in this check will direct diagnosis
concerning "Engine
Crunlis But Won't Run" and the
"Fuel Control System," Section
"6E2-C2", including
diagnosis of an injector, pressure regulator,
fuel pump,
fuel
pump relay, and oil pressure switch.
Idle Air Control (IAC) Valve
A "Scan" tool reads IAC position in steps, calletl
"Counts." "0" steps indicates the ECM is commanding
the
IAC to be driven in, to a fully seiltetl position
(minimum idle air).
The higher the number steps, the
more idle air being allowed to pass
by the IAC valve.
cnose Refer to CHART C-2C for information to cliil,
the function of the IAC valve.
Driva bility
Refer to Section "B" for driveability symptoms
related to the fuel control.
ON-VEHICLE SERVICE
GENERAL SEWVICE INFORMATION
CAUTION:
e To prevent personal injury or damage to the
vehicle
as the result sf an accidental start,
disconnect and reconnect the negative
battery cable before and after service is
performed.
@ Also, catch any fuel that leaks out when
disconnecting the fuel lines, by covering the
fittings with
a shop cloth. Place the cloth in
an approved container when work is
complete.
The 'FBI unit repair procedures cover component
replacement with the unit on the vehicle,
tIowever,
throttle body replacement requires that the complete
unit
be removed from the enginc.

DRIVEABILITY AND EMISSIONS 5.OL (VIN E) 6EZ-C6-3
CAUTION: Do Not Oil A.I.R. Pump
Hoses and Pipes
inspect
1. Hose or pipe for deterioration or holes.
2. All hoses or pipe connections, and clamp tightness.
3. Hose or pipe routing. Interference may cause
wear.
4. If a leak is suspected on the pressure side of the
system or if a hose or pipe has been disconnected
on the pressure side, the connections should be
checked for leaks with a soapy water solution.
With the pump running, bubbles will form if a
leak exists.
Check Valve
a inspect
1. A check valve should be inspected whenever the
hose is disconnected form a check valve or
whenever check valve failure is suspected.
(A
pump that had become inoperative and had shown
indications of having exhaust gases in the pump
would indicate check valve failure).
2. Blow through the check valve (toward the cylinder
head) then attempt to suck back through the check
valve Flow should only be in one
direction(toward the exhaust manifold). Replace
valve which does not operate properly.
ON-CAR SERVICE
DRIVE BELT
Remove or Disconnect
1. Inspect drive belt for wear, cracks or deterioration
and replace if required. When installing new belt,
it must be seated and fully secured in grooves of
all belt driven components.
AIR INJECTION PUMP
Remove or Disconnect
1. Hold pump pulley from turning by compressing
drive belt, then loosen pump pulley bolts.
2. Drive belt and pulley.
3. Hoses, vacuum, and electrical connections from
Air Injection Control valve.
4. Air pump mounting bolts, and pump assembly
(See Figure
C6-3).
Install or Connect
1. Air pump assembly, and tighten mounting bolts.
2. Spacer and pump pulley against centrifugal filter
fan.
3. Pump pulley bolts and tighten equally to 13 N m
(10 lb, ft).
4. Check
air injection system for proper operation
(see Chart C-6).
Figure C6-3 - Air Pump Service
AIR INJECTION CONTROL (PEDES) VALVE
Remove or Disconnect
1. Battery ground cable.
2. Adapter bolts (See Figure C6-4).
3. Air outlet hoses from valve.
4. Splash guard / cover
5. Electrical connectors and vacuum hoses from
valve.
6. Control valve.
Install or Connect
1. Control valve.
2. Electrical connectors.
3. Splash guard /cover
4. Air hoses to valve.
5. Battery ground cable.
6. Check
system operation (see
CHART C-6).

DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-B-3
e A faulty in-tank fuel pump check valve will @ If engine starts but then immediately stalls,
allow the fuel in the lines to drain back to the open
distributor by-pass line. If engine then
tank after the engine is stopped. To check for starts
and runs OK, replace pickup coil.
this condition:
@ If engine starts and stalls, disconnect MAF
Perform Fuel System Diagnosis, CHART A-7. sensor. If engine then runs and sensor
@ Remove spark plugs. Check for wet plugs, connections are OK, replace the sensor.
cracks, wear, improper gap, burned
f lectrodes,
or heavy deposits. Repair or replace as
necessary.
HESITATION, SAG, STUMBLE
Definition: Momentary lack of response as the accelerator is pushed down. Can
occur at all car speeds.
Usually most severe when first trying to make the car move, as
from a stop sign. May cause the engine to stall if severe enough.
Perform careful visual check as described at
start of Section
"B".
a 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.
- PROM (2.8L) or MEM-CAL (5.OL & 5.7L)
number. Also check service bulletins for latest
MEM-CAL or PROM.
- 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.
@ 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
A/C compressor operation
in Owner's Manual.
e Perform careful visual inspection as described
at start of Section
"B".
CHECK:
- TCC and 4th gear switch operation - See
CHART C-8A.
- 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. Also check for plugged EGR
solenoid filter.
- Vacuum lines for kinks or leaks.
- Ignition timing. See Emission Control
Information label.
- In-line fuel filter. Replace ifdirty or plugged.
- Fuel pressure while condition exists. See
CHART A-7.
@ Inspect oxygen sensor for silicone 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 runnig lean
(block learn greater than
138), refer to
"Diagnostic Aids" on
facing page of Code 44. If
the system is running rich (block learn less than
118), refer to "Diagnostic Aids" on facing page of
Code 45.

&E3-B-4 %.8L (VIN S) DRIVEABILITY AND EMISSIONS
LACK OF POWER, SLUGGISH, OR SPONGY
Definition: Engine delivers less than expected power. Little or
no increase in speed when accelerator pedal is pushed down part way.
Perform careful visual check as described at
- EGR operation for being open or partly open all
start of Section
"B". the time - CHART C-7.
e Compare customer's car to similar unit. - Exhaust system for possible restriction: See
Make sure the customer's car has an actual CHART
B-1,
problem.
@ Remove air cleaner and check air filter for
dirt, or for being plugged. Replace as
necessary.
@ CHECK:
- For loose or leaking air duct between MAF
Sensor and throttle body.
- Ignition timing. See Emission Control
Information label.
- Restricted fuel filter, contaminated fuel or
improper fuel pressure. See CHART A-7.
- ECM ground circuits - See ECM wiring
diagrams.
- Inspect exhaust system for damaged or
collapsed pipes.
- Inspect muffler for heat distress or possible
internal failure.
- Generator output voltage. Repair if less than 9
or more than 16 volts.
- Engine valve timing and compression.
- Engine for proper or worn camshaft. See
Section
"6A".
- Secondary voltage using a shop ocilliscope or a
spark tester
5-26792 (ST-125) or equivalent.
DETONATION ISPARK KNOCK
Definition: A mild to severe ping, usually worse under
acceleration. The engine makes sharp metallic knocks that
change with throttle opening. Sounds like popcorn popping.
@ Check for obvious overheating problems:
- Low coolant.
- Loose water pump belt.
- Restricted air flow to radiator, or restricted
water flow thru radiator.
- Inoperative electric cooling fan circuit. See
CHART C-12.
@ CHECK:
- Ignition timing. See Vehicle Emission
Control Information label.
- EGR system for not opening - CHART C-7.
- TCC operation - CHART C-8.
- Fuel system pressure. See CHART A-7.
- PROM or MEM-CAL - Be sure it's the correct
one. (See Service Bulletins)
- Valve oil seals for leaking.
@ Check for incorrect basic engine parts such as
cam, heads, pistons, etc.
@ Check for poor fuel quality.
@ Remove carbon with top engine cleaner. Follow
instructions on can.
@ Check ESC system (5.OL & 5.7L)
See CHART C-5
o 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 runnig 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
l18), refer to "Diagnostic Aids" on facing page of
Code 45.

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".

DRIVEABILITY AND EMISSIONS 2.8L (VIN 5) 6E3-CZ-3
Fuel Cutofl Mode
No fuel is delivered by the injector when the
ignition is "OFF". This prevents dieseling. Also, fuel
is not delivered if no reference pulses are seen from
the distributor, which means the engine is not
running. This prevents flooding.
Fares Control System Components
The fuel control system is made up of the following
parts:
e Fuel Injectors
@ Throttle Body
e Fuel pump relay
@ Fuel Pressure Regulator
@ Fuel Rail
Basic System Operation
The fuel system (Figure C2-3) starts with the fuel
in the fuel tank. An electric fuel pump, located in the
fuel tank with the gage sending unit, pumps fuel to
the fuel rail through an in-line fuel filter. The pump is
designed to provide fuel at a pressure above the
pressure needed by the injectors. A pressure regulator
in the fuel rail keeps fuel available to the injectors at a
constant pressure. Unused fuel is returned to the fuel
tank by a separate line. For further information on
the fuel tank, in-line filter
, and fuel lines , see Section
"6C".
The injectors, are controlled by the ECM. They
deliver fuel in one of several modes, as described
above. In order to properly control the fuel supply, the
fuel pump is operated by the ECM thru the fuel pump
relay and oil pressure switch (see
"Fuel Pump
Electrical Circuit", Code 54).
THROTTLE BODY UNIT
The throttle body has a throttle valve to control
the amount of air delivered to the engine. The TPS
and
IAC valve are also mounted on the throttle body.
The throttle body contains vacuum ports located
at, above, or below the
throttIe valve. These ports
generate the vacuum signals needed by various
components.
FUEL RAIL
The fuel rail is mounted to the top of the engine.
It distributes fuel to the individual injectors. Fuel is
delivered to the input end of the rail by the fuel lines,
goes thru the rail, then to the pressure regulator.
Remaining fuel is then returned to the fuel tank.
Figure C2-3 Fuel System
FUEL INJECTOR
The fuel injector is a solenoid operated device
controlled by the ECM (See Figure C2-4). The ECM
turns
"ON" the solenoid, which opens a valve to allow
fuel delivery. The fuel, under pressure, is injected in a
conical spray pattern at the opening of the intake
valve. The fuel which is not used by the injectors
passes through the pressure regulator before being
returned to the fuel tank.
An injector which is stuck partly open will cause
loss of pressure after engine shut down, so long crank
times would be noticed on some engines. Also,
dieseling could occur because some fuel could be
delivered to the engine after the ignition is turned
"OFF".
PRESSURE REGULATOR
The pressure regulator is a diaphragm-operated
relief valve with injector pressure on one side and
manifold pressure on the other. The function of the
regulator is to maintain a constant pressure at the
injector at all times. The pressure regulator
compensates for engine load, by increasing fuel
pressure when it sees low engine vacuum.

6E3-C6-2 2.8L (WIN 5) DRIVEABILITY AND EMISSIONS
When the solenoid is de-energized, the pressurized
air from the air pump is allowed to enter the decel
timing chamber. This places sufficient pressure on
the metering valve diaphragm to overcome spring
tension, closing the
valve,causing air to divert to the
silencer.
At higher engine speeds, excess air is exhausted to
the silencer through the pressure relief valve. (Figure
C6-1)
Deceleration Valve
To help prevent backfiring during high vacuum
conditions a deceleration (gulp) valve is used to allow
air to flow into the intake manifold (shown in Figure
C6-2). This air enters the airlfuel mixture to lean the
rich condition created by high vacuum when the
throttle valve closes on deceleration.
The vacuum draws the deceleration valve
diaphragm down and opens the valve allowing air
inlet duct to flow into the intake manifold.
RESULTS OF INCORRECT OPERATION
@ If no air (oxygen) flow enters the exhaust stream
at the exhaust ports, HC and
CO emission levels
will be too high.
@ Air flowing to the exhaust ports at all times could
cause
a rich ECM command and increased
temperature of the converter. This may also cause
a Code
44 due to oxygen being pumped passed the
oxygen sensor. There should be no air going to the
exhaust ports while operating in the closed loop
mode.
DIAGNOSIS
The diagnosis of the AIR system is covered in
CHART C-6 at the end of this section.
OPERATIONAL CHECKS
A.I.R. Pump
1. The air pump is a positive displacement vane type
which is permanently lubricated and requires no
periodic maintenance.
Accelerate engine to approximately
1500 rpm's
and observe air flow from
hose(s). If air flow increases
as engine is accelerated, pump is operating
satisfactorily. If air flow does not increase or is not
present, proceed as follows:
Inspect
For proper drive belt tension.
2. For a leaky pressure relief valve. Air may he
heard leaking with the pump running.
DECELERATION VALVE
1 VACUUM BLEED VALVE
1 MANIFOLD VACUUM
1 DECELERATION AIR TO INTAKE
MANIFOLD
1 FILTERED AIR FROM INTAKE DUCT
/ DIAPHRAGM
05 10 84 5s 1726-6E
Figure C6-2 - Deceleration Valve
NOTICE: If the engine or underhood compartment
is to he cleaned with
steam or high-
pressure detergent, the centrifugal filter
fan should be masked "OFF7' to prevent
liquids from entering the pump.
Inspect
3. For a seized Air Injection Pump.
3. Hoses, tubes and all connections for leaks and
proper routing.
5, For air flow from controllswitching valve.
6. AIR injection pump for proper mounting and bolt
torque.
7. If no irregularities exist and the AIR injection
pump noise is still excessive, remove and replace
pump.
CAUTION: Do Not Oil Air Pump
Hoses and Pipes
Inspect
1. Hose or pipe for deterioration or holes.
2. All hoses or pipe connections, and clamp tightness.
3. Hose or pipe routing. Interference may cause
wear

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.