1988 PONTIAC FIERO Service Repair Manual

6E3-C2-10 2.8L (VIN 5) DRIVEABILITY AND EMISSIONS
Inspect
@ All injector O-ring seals (86).
- Replace if damaged.
+++ Assemble [7]
e New O-ring seals (86) as required, on port
i~,jectors (85).
lnstall or Connect
1. Lubricate all injector O-ring seals with engine oil.
2. Port injectors to fuel rail and pressure regulator
assembly
(11).
3. Rotate injector retainer clips (87) to locking
position (Figure C2-12).
Fuel Pressure Regulator
Important
The pressure regulator is factory adjusted and is
not serviceable. Do not attempt to remove the
regulator from the fuel rail.
PORT INJECTORS
Each port injector is located and held in position
by
a retainer clip that must be rotated to release
and/or lock the injector in place, as shown in Figure
C2-13.
FUEL RAIL
85 INJECTOR - PORT
87 CLIP-INJECTOR RETAINER
Figure C2-13 Port lnjector with Injector Retainer Clip
Remove or Disconnect
1. Rotate injector retaining clip(s) (87) to unlocked
position.
2. Injectors
(85).
inspect
@ All injector O-ring seals (86).
- Replace if damaged.
Assemble
@ New O-ring seals (86) as required, on injectors
(85).
Install or Connect
1. Lubricate all injector O-ring seals with engine oil.
2. Injectors
t,o fuel rail and pressure regulator
assembly
(1 1).
3. IZotate injector retainer clips (87) to locking
position (Figure
C2-13).
240PWESSUREREGULATORAND
BASE ASSEMBLY
Figure C2-14 Fuel Pressure Regulator
PRESSURE REGULATOR
Figure
C2-14
important
The pressure regulator is factory adjusted and is
not serviceable.
DO not attempt to remove
regulator cover.
a Remove or Disconnect
1. Front crossover tube rc1;ainer attaching screw
assembly
(235) anri c~-~):,so irer tube retainer (234j.
2. Retainer to base screlv sssembly !273) and re:i!:
crossover tube ret,ai nclr I2701
3. Separate the left hand fuel rail and plug assembly
(200) from the rigl~f, hand fuel rail and tube
assembly
(220).
4. Bracket to rail attaching screw assembly (2561,
bracket to hase attaching screw assembly (258)
and the pressure regulator and base assembly
bracket
(255).
5. Rear hracket attaching study assembly (222).
6. Base to right hancl rail screw assembly (275).

DRIVEABILITY AND EMISSIONS 2.8L (VIN 5) 6E3-CZ-1 l
7. Pressure
regulator and base assembly (240) from
right hand rail assembly (220).
8. Rotate the regulator and base assembly to remove
from the fuel outlet tube.
9. Base to rail connector (250).
Important
When removing 0-Ring seals, note locations and
sizes, to assure correct replacement and re-
assembly.
10. 0-Ring seals:
@ Connector (252).
@ Fuel outlet tube (224).
@ Rear crossover tube (267).
@ Front crossover tube (232).
Install or Connect
1. Lubricate with engine oil, and install 0-Ring
seals:
@ Connector (252).
@ Fuel outlet tube (224).
@ Rear crossover tube (267).
@ Front crossover tube (232).
2. Base
to rail connector (250) in pressure regulator
and base assembly
(240).
3. Regulator and base assembly on fuel outlet tube.
4. Rotate the regulator and base assembly to install
base to rail connector (250) into right hand rail
assembly.
5. Base
to right hand rail screw assembly
(275).
6. Pressure
regulator and base assembly bracket
(255), bracket to base attaching screw assembly
(258) and bracket to rail attaching screw assembly
(256).
7. Rear bracket attaching study assembly (222).
8. Left hand rail and plug assembly (200), with front
and rear crossover tubes (230) and
265), to right
hand rail and tube assembly (220).
9. Rear crossover tube retainer (270) and retainer to
base screw assembly (273).
10. Front crossover tube retainer
(234) and retainer
attaching screw assembly
(235).
COLD START FUEL INJECTION SWITCH
Remove or Disconned
1. Connector.
2. Switch.
n Install or Connect
1. Switch.
2. Connector.
THROTTLE BODY
(Figure
C2-15)
Remove or Disconnect
1. Air inlet duct.
2.
IAC and TPS connectors.
3. Vacuum lines.
4. Coolant hoses (2).
5. Throttle, TV and cruise control cables
6. Throttle body retaining bolts.
Install or Connect
1. Reverse procedure to reinstall.
2. Refill
radiator with lost coolant.
THROTTLE BODY ASSEMBLY
Figure C2-15 Throttle Body Service
THROTTLE BODY SERVICE IDENTIFICATION
An eight digit identification number is stamped
on the throttle body casting next to the coolant cover,
as shown in Figure C2-16. Refer to this model
identification number if servicing or part replacement
is required.
Names of component parts will be found on the
numbered list that accompanies the exploded view
(Figure C2-17). Numbers used to identify parts in the
exploded views also are used to identify the same parts
in other illustrations of this manual.
IDENTIFICATION NUMBER
Figure C2-16 Throttle Body Identification

DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-C2-13
PARTS INFORMATION
PART NAME PART #
............................................. Throttle Body Assembly 10
............................................... . Plug Idle Stop Screw 15
........................................... Screw Assembly . Idle Stop 16
.............................................. . Spring
Idle Stop Screw 17
........................................ Sensor -Throttle Position (TPS) 20
....................................... Screw Assembly . TPS Attaching 21
....................................... Retainer . TPS
Attaching Screw 22
............................................... . Cover Coolant
Cavity 40
............................... Screw Assembly . Coolant Cover Attaching 45
................................. . 0-Ring
Coolant Cover to Throttle Body 46
............................... Idle AirIVacuum Signal Housing
Assembly 60
........................ Screw Assembly . Idle AirIVacuum Signal
Assembly 65
........................ Screw Assembly . Idle AirIVacuum Signal
Assembly 66
............................... . Gasket
Idle Air/Vacuum Signal Assembly 67
................................. . Valve Assembly Idle Air Control (IAC) 70
......................................... . Gasket IAC Valve Assembly 71

6E3-CZ-14 2.8L (VIN S) DRlVEABlLlTV AND EMISSIONS
MINIMUM IDLE SPEED ADJUSTMENT
The idle stop screw (16), used to regulate
minimum idle speed of the engine, is adjusted at the
factory, then is covered with a plug
(15) to discourage
unnecessary readjustment. However,
if it is necessary
to gain access to the idle stop screw assembly, proceed
as shown in Figure C2-18.
Adjust
1. Pierce
the idle stop screw plug (15) with an awl,
and apply leverage to remove it.
2. Adjust idle
stop screw assembly (16) as required.
3. With IAC motor connected, ground diagnostic
lead.
4. Turn "ON" ignition, do not start engine. Wait at
least 30 seconds.
5. With ignition "ON," disconnect IAC electrical
connector.
6. Start engine and allow to go "Closed Loop".
7. Remove ground from diagnostic terminal.
8. Adjust idle stop screw to 550 rpm in drive, 650 rpm
in neutral on manual transmission vehicles.
9. Turn ignition "OFF7' and reconnect connector at
IAC motor.
10.
110 not adjust TPS unless setting is outside of 0.35-
0.67 limits. If adjustment is required, see
procedure in Section
"6l33-Cl".
11. Start engine and inspect for proper idle operation.
IDLE STOP
SCREW
ASSEtVIBLY
SCREW PLUG
* 55 1503-6E
Figure C2-18 Removing ldle Stop Screw Plug
UNIT REPAIR PROCEDURES
The unit repair procedures cover component
replacement with the unit on the vehicle. However,
throttle body replacement requires that the
complete unit be removed from the engine. If
removed, it may be placed on a holding fixture, such as
5-9789-118, BT-3553, or equivalent, to prevent
damage to the throttle valve.
Cleaning and Inspection
Throttle body parts, except as noted below, may be
cleaned in
a cold immersion-type cleaner such as AC
Delco X-55 or equivalent.
NOTICE: The throttle position sensor (TPS), idle air
control
(IAC) valve, throttle body with
cover and seals or gaskets in place, should
NOT be soaked in liquid solvent or
cleaner, as they may be damaged. If TPS
or IAC valve is still mounted in the
throttle body, do not immerse throttle
body.
1. Clean
all metal parts throughly and blow dry with
shop air. Be sure all air passages are free of burrs
and dirt.
2. Inspect mating casting surfaces for damage that
could affect gasket sealing.
IDLE AIR CONTROL VALVE ASSEMBLY AND
GASKET
(Figure
CZ-19)
Remove or Disconnect
1. Electrical connector at idle air control valve
assembly
(70).
2. IAC valve assembly from idle airlvacuum signal
housing assembly
(60).
3. IAC valve assembly gasket (71) and discard.
60 IDLE AIRIVACUUM SIGNAL HOUSING
70 IDLE AIR CONTROL VALVE
(IAC)
71 IAC GASKET
Figure C2-19 ldle Air Control Valve Assembly

DRIVEABILITY AND EMISSIONS 2.8L (VIN S) 6E3-CZ-15
NOTICE: Before instal ling new idle air control valve
assembly, the position of its pintle
MUST
be checked. If pintle is extended too far,
damage to the assembly may occur.
Measure
@ Distance from gasket mounting surface of IAC
valve assembly
(70) to tip of pintle, Dimension
"A" in Figure
C2-19.
Adjust
If distance is greater that 28 mm (1 118 in.), reduce -
it as follows:
a. If
IAC valve assembly has
a "collar" around
electrical connector end, use firm hand pressure
on pintle to retract it. (A slight side-to-side motion
may help.)
b. If IAC valve assembly has "no collar", compress
pintle-retaining spring toward body of the IAC
and try to turn pintle clockwise.
@ If pintle will turn, continue turning until
28mm
(1 118 in.) is reached. Return spring to
original position, with straight part of spring
end lined up with flat surface under the pintle
head.
@ If pintle will not turn, use firm hand pressure
to retract it.
Install or Connect
1. New IAC valve assembly gasket (71) on IAC valve
assembly
(70).
2. IAC valve assembly in idle airlvacuum signal
housing assembly
(60).
Tighten
IAC valve assembly to 18N.m (13 ft. Ibs.), with
wrench on hex surface only.
3. Electrical connector at IAC valve assembly (70).
Important
No physical adjustment is made to the IAC
assembly after installation.
IAC resetting occurs
after reinstallation on the vehicle, and is reset
after the engine is started and then the ignition
turned off.
IDLE AIR / VACUUM SIGNAL HOUSING
ASSEMBLY
(With
IAC Removed) (Figure C2-20)
Remove or Disconnect
1. Idle airlvacuurn signal assembly attaching screw
assemblies
(65) and (66).
2. Idle airlvacuum signal housing assembly (60).
3. Idle airlvacuum signal assembly gasket (67).
10 THROTTLE BODY ASSEMBLY
60 IDLE AIWVACUUM SIGNAL
HOUSING ASSY
65 SCREW ASSY - IDLE AIWVACUUM SIGNAL
HOUSING ASSY.
66 SCREW
ASSY
- IDLE AIWVACUUM SIGNAL
HOUSING ASSY
67 GASKET - IDLE AIR VACUUM SIGNAL ASSY 70 VALVE ASSY - IDLE AIR CONTROL (IAC) 71 GASKET - IAC VALVE ASSY
Figure C2-20 Idle AirIVacuum Signal Housing
Assembly
Tighten
@ Attaching screw assemblies (starting in center
and
moving outward) to 3.0 N.m (27.0 in. Ibs.).
COOLANT CAVITY COVER AND O-RING
(Figure
C2-21)
Remove or Disconnect
1. Coolant cover attaching. screw assemblies (45).
2. Coolant cavity cover (40).
3. Coolant cover to throttle body O-ring (46).
Inspect
@ Gasket and O-ring surfaces, for damage and
corrosion which might effect sealing.
Install and Connect
1. Lubricate coolant cover to throttle body O-ring (46)
with ethylene glycol antifreeze.
2. O-ring in throttle body assembly (10).
:3. Coolant cavity cover.
4. Coolant cover attaching screw assemblies (451,
applying pressure against throttle body (1 0).

6E3-C2-16 2.8L (VlN S) DRIVEABILITY AND EMISSIONS
10 THROTTLE BOBY ASSEMBLY
40 COOLANT CAVITY COVER
45 COOLANT COVER ATTACHING SCREW
46 COOLANT COVER TO f HROTTLE BOBY O-RING
55 1457-6E
Figure C2-21 Coolant Cavity Cover Assembly
a Tighten
@ Screw assemblies to 3.0 Nm (27.0 in. Ibs.).
61 IAWICOOLANT COVER ASSV 62 SCREW ASSV - IAW COVER ASSV TO maomE BODY 63 GASKET - IACV COOLANT COVER TO THROTTLE BODV 70 VALVE ASSV - IDLE AIR CONTROL 71 GASKET - IDLE AIR CONTROL VALVE 5s 1506-6E
Figure 62-22 Idle Air controlICoolant
Cover Assembly
Clean
@ Throttle body gasket mounting surface to
ensure
a good seal .
Sealing surface for damage that could prevent
sealing properly or cause coolant leak.
Install and Connect
1. New [ACVIcoolant cover assembly to throttle body
gasket
(63).
IDLE AIR GONTROLICBOLANT COVER 2. t~~~/coolant cover assembly (61).
ASSEMBLY 3. IACV cover assenlbly to throttle body screw
With Throttle Body Removed From Enqine assemblies (62). - (Figure C2-22) Tighten
Remove or Disconnect @ Screw assemblies to 3.0 N.m (27.0 in. lbs.).
1. Idle air control (IAC) valve assembly (70) from 4. IAC valve assembly (70). (See "Idle Air Control
IACVIcoolant cover assembly. (See "Idle Air Valve
and Gasltet" section.)
Control valve and Gasket" section.)
2.
IACV cover assembly to throttle body screw NOTICE: Before installing the IAC valve assembly
assemblies (62). the
position of its pintle MUST be
checked.
If pintle is extended too far, damage to the
3. Cover assembly (61).
4. Cover assembly to throttle body gasket (63). assembly may occur. (See "Idle Air
Control Valve and Gasket" section.)

DRIVEABILITY AND EMISSIONS 2.8L (VIN 5) 6E3-C2-17
FUEL PUMP RELAY
The fuel pump relay is mounted in the engine
compartment (see Figure C2-23). Other than checking
for loose connectors, the only service possible is
replacement.
rBRAKE BOOSTER /FUEL PUMP RELAY
/ /FAN RELAY
RELAY
Y '"ccONT"L
BULKHEAD
FORWARD
LAMP HARNESS
Figure C2-23 Fuel Pump Relay
OIL PRESSURE SWITCH
The oil pressure switch is mounted as shown in
Figure C2-24.
Remove or Disconnect
1. Electrical Connector.
2. Oil Pressure Switch.
Install or Connect
1. Make sure fittings (41) are properly aligned to
allow switch installation.
2. Oil Pressure Switch.
3. Electrical Connector.
PARTS INFORMATION
PART NAME GROUP
Injector, fuel ......................... 3.300
Pump, Fuel (In-Tank)
................... 3.900
Relay, Fuel Pump
..................... 3.900
Switch, Oil Pressure.
................... 1.800
Valve Asm, Idle Air Control
: Part
Of Control Kit, Idle Air Valve.
.......... 3.820
Regulator, Fuel Pressure
................ 3.164
Rail, Fuel Feed. ....................... 3.330
PRESSURE SWI
Figure C2-24 Oil Pressure Switch