1988 PONTIAC FIERO Service Repair Manual

6E2-CZ-10 DRlVEABlLlTV AND EMISSIONS - 5.OL (WIN E)
FUEL METER BODY ASSEMBLY
THROTTLE BODY TO FUEL METER BODY GASKET
- 13 FUEL OUTLET NUT CASKET
1 FUEL OUTLET NUT - 1 FUEL$ETURN LlNE "Ow RING
1 FUEL INLET LlNE "Ow RlNG
FUEL INLET NUT
1 FUEL INLET NUT GASKET
1 THROTTLE BODY ASSEMBLY
FUEL
MmER BODY - TWROmLE BODY AWACHING
SCREW ASSEMBLY
Figure C2-14 - Fuel Meter Body Assembly
8. Fuel
meter body assembly from throttle body
assembly.
9. Throttle ,)ody to fuel meter body gasket and
discard.
a Install or Connect
1. New throttle hody to fuel meter body gasket.
Match cut-out portions in gasket with openings in
throttle body.
2. Fuel meter body assembly on throttle body
assembly.
3. Fuel meter body-to-throttle hody attaching screw
assemblies, coated with approriate locking
compound.
Tighten
@ Screw assemblies to 4.0 N.m (35.0 Ib. in.).
4. Fuel inlet and outlet nuts with new gaskets to
fuel meter body assembly.
Tighten
e Inlet nut to 40.0 N.m (30.0 lb. ft.).
Outlet nut to 29.0 N.m (21.0 lb. ft.).
5. Fuel inlet and return lines and new o-rings. (Use
back-up wrench J-29698-A or BT-8251-A to keep
TBI nuts from turning.)
Tighten
@ Fuel lines to 23 N.m ( 17 lb. ft.).
6. Injectors,
with new upper and lower o-rings in fuel
meter body assembly.
7. Fuel meter cover gasket, fuel meter outlet gasket,
and pressure regulator seal.
8. Fuel meter cover assembly.
9. Long and short fuel meter cover attaching screw
assemblies, coated with appropriate thread
locking compound.
Tighten
e Screw assemblies to 3.0 N.m (27.0 lb.in.1.
10. Electrical connectors to fuel injectors.
11. With engine "OFF," and ignition "ON," check for
leaks around fuel meter body, gasket and around
fuel line nuts.
12] BOLT (2)
Figure C2-15 - TPS Service
THROTTLE POSITION SENSOR (TPS)
Replacernent (Figure CZ-15)
Remove or Disconnect
1. Electrical connector.
2. Two 'I'PS attaching screw assemblies and
retainers, (if applicable).
3. TPS from throttle body assembly.
NOTICE: The TPS is an electrical component and
must not be soaked in any liquid cleaner
or solvent, as damage may result.

DRIVEABILITY AND EMISSIONS - 5.0L (VIN E) 6EZ-CZ-11
IDLE AIR CONTROL (IAC) VALVE
IAC VALVE GASKET
THROTTLE BODY ASSEMBLY
Figure C2-16 - Thread-Type IAC Valve
Install or Connect
1. TPS on throttle body assembly, while lining up
TPS lever with TPS drive lever on throttle body.
2. Two
TPS attaching screw assemblies.
Tighten
@ Screw assemblies to 2.0 N-m (18.0 in.lbs.).
3. Electrical connector.
4. Check for TPS output as follows: - Use an ALDL scanner to read TPS output
voltage.
- With ignition "ON" and engine stopped, TPS
voltage should be less than 1.25 volts. If more
than 1.25 volts, replace TPS.
IDLE AIR CONTROL (IAC) VALVE
Replacement (Figure CZ-16)
NOTICE:
The IAC valve is an electrical
component
and must not be soaked in any liquid
cleaner or solvent. Otherwise
damage
could result.
Important
All thread-mounted IAC valves on Model 220 TBI
units have a dual taper, 10 mm diameter, pintle.
Any replacement of an IAC valve must have the
correct part number with the appropriate pintle
taper and diameter for proper seating of the valve
in the throttle body.
Remove or Disconnect
1. Electrical connector.
2. IAC valve, using 32 mm (1-114") wrench.
3. IAC
valve gasket and discard.
Clean
@ Old gasket material from surface of throttle body
assembly to insure proper seal of new gasket.
NOTICE: If the IAC valve has been removed during
service, its operation may be tested
electrically with the
IACIISC Motor Tester
(Available Tool
# 5-37027, or BT-8256K).
However, if the valve pintle is extended
electrically, it must also be retracted
electrically. Under no circumstances
should the valve pintle be tampered with
by hand, screwed, or pushed in, or pulled
out, as damage could occur.
Important
No physical adjustment of the IAC valve assembly
is required after installation. The IAC valve is
reset by the ECM. When the vehicle is operated at
normal engine temperature at approximately 40
mph (64
kmlhr.), the ECM causes the valve pintle
to seat in the throttle body. The ECM then resets
the pintle to the correct position. Proper idle
regulation should result.
Install or Connect
1. IAC valve with new gasket into throttle body
NOTICE: New IAC valves that have been preset
at the factory should be installed in
the throttle
body in an "as is"
condition, without any adjustment.
Tighten
@ IAC valve assembly to 18.0 N.m (13.0 lb. ft.)
with 32 mm
(1-114") wrench.
2. Electrical connector to IAC valve.
3. Start engine and allow engine to reach operating
temperature.
Important
When the engine is turned "OFF," the IAC valve
will be reset by the ECM.
THROTTLE BODY ASSEMBLY
Replacement (Figure CZ-8)
NOTICE:
Procedures related to replacement of the
individual components below have been
described previously and should be
followed, or damage could occur.
Remove or Disconnect
1. Throttle body injection unit, described below
2. Fuel
meter body-to-throttle hodv attaching ~CI'PW
.i~~rmhlie

6E2-C2-12 DRIVEABILITY AND EMISSIONS - 5.0b (VIN E)
3. Fuel meter body assembly.
4. Throttle body-to-fuel meter body gasket. Discard
gasket.
a Disassemble
@ TPS from old throttle body, according to previous
instructions, for reuse on new throttle body. (New
IAC valve comes with new throttle body.)
Assemble
@ TPS onto replacement throttle body assembly,
according to previous instructions.
Install or Connect
1. New throttle body-to-fuel meter body gasket.
2. Fuel meter body assembly on throttle body
assembly.
3. Fuel meter body-throttle
body attaching screw
assemblies that have been coated with locking
compound.
Tighten
@ Attaching screw assemblies to 4.0 N.m
(35.0 Ib. in.).
4. TBI
unit onto engine, as described below.
MllMiMhlM IDLE SPEED CHECK
The idle stop screw, used in mechanically setting
minimum engine idle speed has been set at the factory
and should not require further adjustment. However,
to check that the setting is correct, proceed as follows:
I. Plug any vacuum ports, as required.
2. If present, remove idle stop screw plug by piercing
it with an awl, then applying leverage (Figure
C2-17).
3. Connect tachometer to engine.
4. With IAC valve connected, ground the diagnostic
terminal
(ALDL connector).
5.
Turn "ON" ignition, do not start engine. Wait at
least 45 seconds (this allows IAC valve pintle to
extend and seat in throttle body).
6. With ignition "ON," engine stopped, test terminal
still grounded, disconnect
IAC valve electrical
connector.
7, Remove ground from diagnostic terminal and
"startJ' engine. With transmission in neutral,
allow engine rpm to stabilize.
8. The tachometer should read 400 - 450 rpm. If not,
adjust the idle stop speed screw accordingly.
9. Turn ignition "OFF" and reconnect IAC valve
electrical connector.
10. Use silicon sealant or equivalent to cover
minimum idle adjustment screw hole.
11. Unplug any plugged vacuum ports.
1 BOLT - TIGHTEN TO 16 N,rn (12 FT. LBS.)
TBI UNIT
1 GASKET (MUST BE INSTALLED WITH STRIPE FACING UP) ENGINE INTAKE MANIFOLD
Figure C2-18 - Replacing TBI 220 Unit

DRIVEABILITY AND EMISSIONS - S.0L (VIN E) 6EZ-C2-13
"THROTTLE BODY INJECTION (TBI) UNIT
Replacement (Figure C2-18)
a Remove or Disconnect
1. THERMAC hose from engine fitting.
2. Electrical connectors to IAC valve, TPS and fuel
injectors.
3. Grommet with wires from throttle body.
4. Throttle linkage, return
spring(s) transmission
control cable and cruise control (wherever
applicable).
5. Vacuum hoses (noting position of hoses) and
bracket.
6. Fuel inlet and return lines (use back-up wrench
J-29698-A or BT-8251-A). Discard o-
rings from
nuts.
7. TBI mounting hardware.
8. TBI flange (manifold mounting) gasket and
discard.
NOTICE: Stuff manifold opening with a rag to
prevent material from entering
engine, and remove old gasket
material from surface of intake
manifold.
Inspect
@ Intake manifold bore for loose parts and foreign
material, etc.
@ Intake manifold sealing surface for cleanliness.
Install or Connect
1. New TBI flange (manifold mounting) gasket.
2.
TI31 with mounting hardware.
Tighten
@ Hardwareto, 16.5N-m( 12Ib. ft.).
3. New o-rings on fuel line nuts
4. Fuel inlet and outlet lines.
Tighten - @ To 23 N.m (17 lb. ft.). (Use back-up wrench
J-29698-A or BT-8251-A to keep TBI nuts
from turning.)
5. Vacuum hoses and bracket.
6. Throttle linkage, return
spring(s) transmission
control cable and cruise control (wherever
applicable).
7. Grommet with wire harness to throttle body.
8. Electrical connectors, making sure connectors are
fully seated and latched.
9. Check to see if accelerator pedal is free by
depressing pedal to the floor
and releasing while
engine is "OFF".
10. With engine "OFF," and ignition "ON," check for
leaks around fuel line nuts.
11. Start engine and check for fuel leaks.
FUEL HOSEIPIPE ASSEMBLIES
Materials
Fuel Lines. These are welded steel tubes, meeting GM
Specification 124-M, or its equivalent. The fuel feed
line is
318" diameter, and the fuel return line is 5/16"
diameter. Do not use copper or aluminum tubing to
replace steel tubing. Those materials do not have
satisfactory durability to withstand normal vehicle
vibr, ii t' lon.
Clamps. These are stainless steel, screw band type
clamps,
#249472, or equivalent.
Coupled Hose. These are not to be repaired and are
replaced
&as an assembly.
Uncoupled Hose. Use only reinforced fuel resistant
hose, made of "fluroelastomer" material.
[lo not use w
hose within 4 inches (100 mm) of any part of the
exhaust system, or within 10 inches
(254 mm) of the
catalytic converter. The hose's inside diameter nus st
match the outside diameter of the steel tubing.
Fuel Line Repair
1. Cut
a piece of fuel hose 4 inches (100 mm) longer
than the section of line to be removed. If
more
than 6 inches (152 tnm) is to be removed, use a .
combination of steel pipe and hose. The
hose
length should not be more than 10 inches total.
2. Cut a section of pipe to be replacccl, with a tube
cutter. C'se the first step of a double flaring tool to
form a bead on the ends
of the pipe and also, on the
new section of pipe, if used.
3. Slide
the hose
clanlps onto the pip2 and push the
hose
2 inches (51 mm) onto each portion of the fuel
pipe. Tighten a
clamp on each side of the repair.
4. Secure
fuel line to the frame.
FUEL PUMP RELAY
(Figure
CZ-19)
The fuel pump relay is mounted in the engine
compartment. Other than checking for loose
connectors, the only service possible is replacement.
OIL PRESSURE SWITCH
(Figure C2-20)
The oil pressure switch is li~ounted on the engine.
This switch is a parallel power supply, with the fuel
pump relay, and will provide battery voltage to the
fuel
pump, after approximately 28 kPa (4 psi) oil
pressure is reached.

SWITCH ASM
Figure C2-20 - Oil Pressure Switch
PART D INFORMA"F0N
PART NAME GROUP
Meter Kit, Fuel. . . . . . . . . . . . . . . . . . . . . . 3.734
Injector Kit, Fuel. . . . . . , . . . . . . . . . . . . . 3.774
Pump, Fuel (In Tank). . . . . . . . . . . . . . . . . 3.900
Relay, Fuel Pump. . . . . . . . , . . . . . . . . . . . 3.900
Switch, Oil Press. . . . . . . . . . . . . . . . . . . . . 1.800
Throttle Body Injection Unit. . . . . . . . . . . . 3.725
Control Kit, Idle Air Valve. . . . . . . . . . . . . . 3.820

BLANK

6E2-CZ-16 DRIVEABILITY AND EMISSIONS - 5.OL (WIN E)
CHART C-2C
IDLE AIR CONTROL (IAC) VALVE CHECK
5.OL (VIN E) "F'" SERIES (TBI)
Circuit Description:
The ECM controls idle rprn with the IAC valve. To increase idle rpm, the ECM moves the IAC valve out,
allowing more air to pass by the throttle plate. To decrease rpm, it moves the IAC valve in, reducing air flow by
the throttle plate. A "Scan" tool will read the
ECM commands to the IAC valve in counts.
The higher the
counts, the more air allowed (higher idle). The lower the counts, the less air allowed (lower idle).
Test Description: Numbers below refer to circled
numbers on the diagnostic chart.
1. Continue with test, even if engine will not idle. If
idle is to 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
may 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.
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 100 or more
counts. When performing this test, immediately
note rprn on start up, because, on a warm engine,
the rprn will decrease rapidly.
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
CKTs
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:
A slow unstable idle may be caused by a system
problem that cannot be overcome by the
IAC. "Scan"
counts will be above 60 counts, if too low,
and "0"
counts, if engine speed is too high.
If idle is too high, stop engine. Ignition "Oh'".
Ground diagnostic terminal. Wait 30 seconds for
IAC to seat, then, disconnect IAC. Lnground
diagnostic terminal and start engine. If idle speed is
above 450 rprn in drive, locate and correct vacuum
leak. If rpm is less than 450 rpm,
ad,jrlst minimum
idle speed, or correct other conditions, which may
affect idle. refer to Rough Unstable or Incorrect Idle,
in Symptoms, Section
"R".
@ System too lean (Hi.gh AirJFuel Ratio)
Idle speed may be too high or too low. Engine
speed may vary up and down, disconnecting IAC
does not help. May set Code
33.
"Scan" and/or Voltmeter will read an oxygen
sensor output less than 300 mv
(.3 volts). Check
for low regulated fuel pressure or water in
fuel. A
lean exhaust, with an oxygen sensor outpirt fixed
above 800
mv (.8 volts), will be a contaminated
sensor, usually silicone. This may also set
a Code
45.
@ System too rich (Low AirIFuel Ratio)
Idle speed too low. "Scan" counts usually above
80. System obviously rich and may exhibit black
srnoke exhaust.
"Scan" tool and/or Voltmeter will
read an oxygen
sensor signal fixed above 800
mv (.8 volts).
Check:
- High fuel pressure
- Injector leaking or sticking
@ Throttle Body. Remove IAC and inspect bore for
foreign material or evidence of
IAC valve
dragging the bore.
@ If above ;
e all OK, refer to "Rough, Unstable,
Incorrect Idle or Stalling", in Symptoms, Section
"I<".

DRIVEABILITY AND EMISSIONS - 5.OL (VIN E) 6E2-C2-17
ST TERMINAL.
ETWEEN EACH IAC