PONTIAC FIERO 1988 Service Repair Manual

682-6 POWER HEAD ASSEMBLY
16. PRIMARY DIAPHRAGM
17. PRIMARY SUPPORT PLATE 19. HOUSING DIVIDER 20. SECONDARY
DIAPHRAGM
41. POWER PISTON ASSEMBLY
Figure 10 Assembling Primary Diaphram and Support
A, '15 h 15. DIAPHRAGM RETAINER 32. P'JSHROD
42. TOOL J28458
Figure 11 Sealing Diaphragm Retainer
3. Reaction disc (22) and reaction piston (23) from
reaction body
(25).
4.
Air valve spring (26) and reaction bumper (27)
from end of air valve pushrod (32).
5. Retaining ring (28) from air valve pushrod
assembly (32) using No. 2 Truarc pliers or
equivalent.
6. Air valve pushrod assembly (32) by inserting
screwdriver through
pushrod eyelet and pulling
straight out.
e Considerable force will be required.
7. Filter (29), retainer (30) and O-ring (3 1) from air
valve
pushrod assembly (32).
e Power piston for cracks.
e Rubber parts for cuts or nicks.
Air valve
pushrod assembly for corrosion.
Replace
part(s) if any of the preceding are found.
Clean
All parts in clean denatured alcohol.
e ~r~-with unlubricated compressed air.
22. REACTION DISC 29. FILTER 23. REACTION PISTON 30. RETAINER 24. REACTION BODY 31. O-RING RETAINER 32. AIR VALVE 25. REACTION BODY PUSHROD 26. AIR VALVE SPRING 33. POWER PISTON 27. REACTION BUMPER 28. RETAINING RING
HMO01 2.5D2-A6
Figure 12 Power Piston Assembly
Assemble
Lubricated O-ring (31) onto air valve pushrod
assembly (32).
Air valve pushrod assembly (32) into power
piston
(41).
Retainer (30) and seat using appropriate Retainer
Installer
(44).
Filter (29) over pushrod eyelet into power piston
(41).
Retaining ring (28) onto air valve pushrod
assembly (32) using No. 2 Truarc pliers or
equivalent.
Reaction bumper
(27), air valve spring (26).
Reaction piston (23) and reaction disc (22) into
reaction body
(25).
Reaction body (25).
Reaction body retainer (24).

POWER HEAD ASSEMBLY 5D2-7
30. RETAINER
41. POWER PISTON
ASSEMBLY
44, RETAINER INSTALLER HMO01 3-5D2-AB
Figure 13 Retainer Assembly
GAGING PROCEDURE
Tool Required:
J 22647 Push Rod Height Gage
(Figure 15)
e After assembly of booster, position J 22647 Gage
(43) over piston rod (12).
e If piston rod (12) height is not within GO-NO
GO limits of gage
(43), use a service-adjustable
piston rod to obtain correct height.
12. PISTON ROD 43. GAGE J22647
43 b
Figure 15 Gaging Piston Rod
41. POWER PISTON
ASSEMBLY
44. RETAINER
INSTALLER
HM0014-5D2.AB
Figure 14 Installing Retainer Into Piston

SPECIFICATIONS AND SPECIAL TOOLS
GENERAL SPECIFICATIONS
Item mm In.
Front Disc Brake Rotor
Rotor Diameter.
............................................................. 267.00 10.5
LateralRunout .............................................................. 0.13 0.005
Thicknessvariation .......................................................... 0.013 0.0005
Rotor Thickness (Maximum)
................................................... 26.5 1.043
Minimum Thickness After Refinish
.............................................. 24.84 0.980
*DiscardThickness ........................................................... 24.5 0.965
Rear Disc Brake Rotor
Rotor Diameter.
............................................................. 267.00 10.5
LateralRunout .............................................................. 0.13 0.005
Thickness Variation
.......................................................... 0.01 3 0.0005
Rotor Thickness (Maximum)
................................................... 26.47 1.042
Minimum Thickness After Refinish
.............................................. 25.04 0.986
*DiscardThickness ........................................................... 24.3 0.956
Drums
InsideDiameter ............................................................. 241.00 9.5
Maximum
Rebore Diameter. ................................................... 242.81 9.56
*Discard Diameter.
........................................................... 243.59 9.59
Runout ................................................................ 0.15 0.006
*All brake drums and rotors have a discard dimension cast into them. This is a wear dimension and not a refinish dimension.
Any drum or rotor which does not meet the specification should be replaced.
TORQUE SPECIFICATIONS
Item N-m
BrakePedaltoBracketNut .......................................... 34
Booster to Pedal Bracket Nut.
........................................ 2 1
Master Cylinder to Booster Nut
....................................... 27
Parking Brake Control Assembly to Floor Pan Bolt
........................ 10
Brake Hose to Caliper Bolt
........................................... 45
BrakePipe ....................................................... 15
Caliper Mounting Bolt.
.............................................. 50
Wheel Cylinder Bleeder Valve
........................................ 6
Backing Plate to Axle Housing Nut.
.................................... 58
Caliper Bleeder Valve.
.............................................. 13
Junction Block to Rear Axle Bolt
...................................... 27
InletTubeNut ..................................................... 17
AnchorPinNut .................................................... 140
Master Cylinder to Combination Valve Pipe.
............................. 23
Parking Brake Caliper Lever Nut
...................................... 48
Lbs. Ft. Lbs. In.

5F-2 SPECIFICATIONS AND SPECIAL TOOLS
SPECIAL TOOLS
Number Name
J7624 ............................................................................... Spannerwrench
................................................................ J 8049 Brake Spring Remover and Installer
J8057 ............................................................................. Brakespringpliers
J21177A ............................................................ DrumtoBrakeShoeClearanceGage
J21472 .............................................................................. Bleederwrench
J22647 .......................................................................... PushrodHei ghtGage
J23072 ............................................................................... Pistonlnstailer
............................................. J 23456 Power Brake Booster Disassembly and Reassembly Tool
J26267 ...................................................................... BootSeallnstaller(64mm)
J28434 ................................................................. WheelCylinderBleederWrench
J28458 ............................................................................. Retainerlnstaller
.............................................................. J 29282 Air Valve Pushrod Retainer Installer
........................................................................ J 29381 Dust Boot Seal Installer
J29532 .......................................................................... PowerBrakeBleeder
J29567 ......................................................................... Br akeBleederAdapter
J29803 .............................................................................. 1.S.O.FlaringKit
................................................................ J 29839 Brake Cylinder Retainer Remover
.................................................................. J 35856 Proportioning Valve Depressor

ENGINE GENERAL INFORMATION 6-1
SECTION 6
NE GENERAL NFORMAT
Description ............................................................... 6 TBI ...................................... .. ...... 6E2 ................ Engine Mechanical Multi Port Fuel Injection (MPFI) 6E3 -
............................................... 2.8L V-6 ....................................................... 6A2 Exhaust Systems 6F
5.OL V-8 ......................................................... 6A3 ~~~~~~l ~~f~~~~ti~~ ..................................... 6-2
............................ Engine Cooling ...................................................... 6B Engine Performance Diagnosis 6-3 ............................. Engine Fuel 6C Engine Mechanical Diagnosis
6-3 ........................................................... ................................... Engine Knock Diagnosis 6-4
Engine Electrical ................................................... 6D Compression Test ...................................... ... 6-5
................... Driveability and Emission Controls ...................... 6E Oil Leak Detection .. ..................... 6-5
ALL NEW GENERAL MOTORS VEHICLES ARE CERTIFIED BY THE UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY AS CONFORMING TO THE REQUIREMENTS OF
THE REGULATIONS FOR THE CONTROL OF AIR POLLUTION FROM NEW MOTOR VEHICLES.
THlS CERTIFICATION IS CONTINGENT ON CERTAIN ADJUSTMENTS BEING SET TO
FACTORY STANDARDS. IN MOST CASES, THESE ADJUSTMENT POINTS EITHER HAVE
BEEN PERMANENTLY SEALED AND/OR MADE INACCESSIBLE TO PREVENT
INDISCRIMINATE OR ROUTINE ADJUSTMENT IN THE FIELD. FOR
THlS REASON, THE
FACTORY PROCEDURE FOR TEMPORARILY REMOVING PLUGS, CAPS, ETC., FOR
PURPOSES OF SERVICING THE PRODUCT MUST BE STRICTLY FOLLOWED AND,
WHEREVER PRACTICABLE, RETURNED TO THE ORIGINAL INTENT OF THE DESIGN.
DESCRIPTION OF: SECTION 6
SECTION 6A - ENGINE MECHANICAL used for each carburetor. TBI units are described in
This section general contains information on the Section 6E.
mechanical parts of the engine, such as block,
crankshaft, pistons, valve train, and camshaft, that are
common to most engines. Overhaul procedures,
removal and replacement procedures, and
s~ecifications are also covered. Subsections furnish
detailed information on each specific engine. Service
SECTION 6D - ENG l N E ELECTRICAL
information is also given that relates to that engine's
use in each
Carline. Specific subsections are: Items
covered in this section are battery,
generator, starter, primary and secondary ignition,
6A2
- 2.8L V-6 Engine
engine wire harness, spark plugs and wires, and
6A3
- 5.OL V-8 Engine
ignition switch.
SECTION 6B - ENGINE COOLING
Engine cooling system components such as
radiator, water pump, thermostat, and cooling fan, are
covered in this section. Accessory drive belts are also
covered, along with cooling system capacities.
SECTION 6C - FUEL SYSTEM
This section contains information on all the parts
of the fuel system
except the carburetor, or Throttle
Body Injection unit (TBI) itself. Items covered are fuel
tank, fuel pump, and fuel lines. Specific subsections are
SECTION 6E - DRIVEABILITY AND EMISSIONS
This section covers emission control systems
general information, and diagnostic procedures which
will lead to repairing performance and driveability
related problems for gasoline engine equipped vehicles.
All emission components are covered, as well as all
removal and replacement procedures. Instructions on
use of special tools are also given. Specific sections are:
6E
- Driveability and Emissions
6E2
- Fuel Injection (TBI)

6-2 ENGINE GENERAL INFORMATION
6E3 - Fuel Injection (Ported) This section has information
on all exhaust
system parts, such as tailpipes, mufflers, and the
SECTION 6F - EXHAUST SYSTEM catalytic converter.
GENERAL INFORMAflION
CLEANLINESS AND CARE
An automobile engine is a combination of many
machined, honed, polished and lapped surfaces with
tolerances that are measured in the ten-thousandths of
an inch. When any internal engine parts are serviced,
care and cleanliness are important. A liberal coating of
engine oil should be applied to friction areas during
assembly, to protect and lubricate the surfaces on
initial operation. Throughout this section, it should be
understood that proper cleaning and protection of
machined surfaces and friction areas is part of the
repair procedure. This is considered standard shop
practice, even if not specifically stated. PREVENTING
DAMAGE AND IN
CONTRIBUTING TO RELIABLE ENGINE
PERFORMANCE.
When raising or supporting the engine for any
reason, do not use a jack under the oil pan. Due to the
small clearance between the oil pan and the oil pump
screen, jacking against the oil pan may cause it to be
bent against the pump screen resulting in a damaged
oil pick-up unit.
When working on the engine, remember that the
12-volt electrical system is capable of causing short
circuits. When performing any work where electrical terminals could possibly be grounded, the ground cable
of the battery should be disconnected at the battery.
Any time the carburetor or air cleaner is
train components are removed removed, the intake opening should be covered. This for service, they should be in order' will protect against entrance of foreign be installed in the same locations, and with the same material, which could follow the intake passage into mating surfaces, as when removed
the cylinder and cause extensive damage when the -
Battery cables should be disconnected before any engin; is started.
major work is performed on the engine. Failure to IN THE MECHANICAL PROCEDURES
disconnect cables may result in damage to wire harness DESCRIBED IN THIS SECTION, GENERALLY
or other electrical parts. NO
REFERENCES WILL BE MADE TO THE
REMOVAL OF OPTIONAL EQUIPMENT SUCH
ENGINE SERVICE AS POWER STEERING PUMP, AIR
CONDITIONING COMPRESSOR, ETC.
THE FOLLOWING INFORMATION ON SHOULD IT BECOME NECESSARY TO
ENGINE SERVICE SHOULD BE NOTED REMOVE ANY SUCH ITEM TO
PERFORM
CAREFULLY, AS IT IS IMPORTANT IN OTHER SERVICE, REFER TO THE
APPROPRIATE SECTION OF THIS SERVICE
MANUAL FOR SPECIFIC INFORMATION.
ENGINE PERFORMANCE DIAGNOSIS
INTRODUCTION interchangeably for so long, it was necessary to decide
on the most common usage and then define them. If the
Engine Performance procedures are definition is not understood, and the exact Symptom is
guides that will lead to the most probable causes of not used, the Diagnostic procedure will not work. engine performance complaints. They cover the
components of the fuel, ignition, and mechanical It
is important to keep two facts in mind:
systems that could cause a particular
complaint, and 1. The procedures are written to diagnose problems
then outline repairs in a logical sequence. on cars
that have
"run well at one time" and
that time and wear have created the condition.
It is important to determine if the
"Service ~~~i~~ soon- light is "ON,~' or has come for 2. All possible causes cannot be covered,
a short interval while driving. If the
"Service Engine particularly with regard to emission controls. If
Soon" light has come "ON," the Computer doing the work prescribed does not correct the
Command Control System or DECS should be complaint, then either the wrong Symptom was
checked for stored
"Trouble Codes" (See Diagnostic used, or a more detailed analysis will have to be
Circuit Check, Section 6E, for the engine you are made.
working on) which may indicate the cause for the All of the Symptoms can be caused by worn out
performance
complaint.Each Symptom is defined, and or defective parts such as Spark Plugs, Ignition
it is important that the correct one be selected, based Wiring, etc. If time and/or mileage indicate that
on the complaints reported or found. The definition of parts should be replaced, it is recommended that
each symptom is included with the symptom. it
be done.
The words used may not be what you are used to Refer to:
in all cases, but because these terms have been used
@ Section 6E - Driveability and Emissions

ENGINE GENERAL INFORMATION 6-3
B, Section 6E2 - Fuel Injection (TBI)
B, Section 6E3 - Fuel Injection (Ported)
ENGINE MECHANICAL DIAGNOSIS
The following diagnostic information covers common problems and possible causes. When
the proper diagnosis is made, the problem should be corrected by adjustment, repair or part
replacement as required. Refer to the appropriate section of the manual for these procedures.
EXCESSIVE OIL LOSS
B, External oil leaks. Tighten bolts and/or replace o Continuous high speed driving, and/or severe
gaskets and seals as necessary. usage
such as trailer hauling, will normally cause
decreased oil mileage.
e Improper reading of dipstick. Check oil with car PCV system malfunctioning. on a level surface and allow adequate drain-down Valve guides and/or valve stem seals worn, or time.
seals omitted. Ream guides and install oversize
service valves and/or new valve stem seals.
Improper Use S.A'E' Piston rings broken, worn, or not seateded. Allow viscosity for prevailing temperatures. See
adequate time for rings to seat. Replace broken
Owner's Manual for proper specifications.
or worn rings, as necessary.
Piston improperly installed or misfitted.
LOW OIL PRESSURE
Slow idle speed. Set idle speed to correct
specification, if not ECM controlled.
Incorrect, or malfunctioning, oil pressure switch.
Incorrect, or malfunctioning, oil pressure gage.
Replace with proper gage.
.*
Improper oil viscosity, or diluted oil. install oil of
proper viscosity for expected temperature, or
install new oil if diluted with moisture or
unburned fuel mixtures.
o Oil pump worn or dirty.
e Plugged oil filter.
e Oil pickup screen loose or plugged.
B, Hole in oil pickup tube.
e Excessive bearing clearance. Replace if necessary.
o Cracked, porous or plugged oil galleys. Repair or
replace block.
o Galley plugs missing or misinstalled. Install
plugs, or repair as necessary.
VALVE TRAIN NOISE
e Low oil pressure. Repair as necessary. (See o Broken valve spring.
preceding diagnosis for low oil pressure.)
o Sticking valves.
o Loose rocker arm attachments. Inspect and B, Lifters worn, dirty, or defective. Clean, inspect,
test and replace as necessary.
repair as necessary.
o Camshaft worn, or poor machining. Replace
o Worn rocker arm and/or pushrod. camshaft.
B, Worn valve guides.
ENGINE KNOCK DIAGNOSIS
KNOCKS COLD AND CONTINUES FOR TWO TO THREE MINUTES
INCREASES
WITH TORQUE
o Vacuum operated EFE engines may have valve o Excessive piston to bore clearance. Replace
knock. Replace EFE valve. piston.
e Flywheel contacting splash shield. Reposition
splash shield.
e Loose or broken balancer or drive pulleys.
Tighten, or replace as necessary. Cold engine piston knock usually
disappears when the cylinder is grounded
out. Cold engine piston knock which
disappears in 1.5 minutes should be
considered acceptable.

6-4 ENGINE GENERAL INFORMATION
Bent connecting rod.
HEAVY KNOCK H0"FVVI"F TORQUE APPLIED
Broken balancer, or pulley hub. Replace parts as e Exhaust system grounded. Reposition as
necessary. necessary.
Loose torque converter bolts. Flywheel
cracked.
e Excessive main bearing clearance. Replace as
Accessory belts too tight or nicked. Replace
necessary.
and/or tension to specs as necessary.
e Excessive rod bearing clearance. Replace as
necessary.
LIGHT KNOCK HOT
Detonation or spark knock. Check operation of e Loose torque converter bolts.
EST or ESC (See Section
6D or 6E). Check e Exhaust leak at manifold. Tighten bolts and/or
engine timing and fuel quality.
replace gasket.
8 Excessive rod bearing clearance. Replace
bearings as necessary.
KNOCKS ON INITIAL START-UP BUT ONLY LASTS A FEW SECONDS
Noisy mechanical fuel pump. Replace pump.
When the engine is stopped, some valves
will be open. Spring pressure against lifters
Improper oil viscosity. Install proper oil viscosity will
tend to bleed lifter down. Attempts to
for expected temperatures. See Owner's Manual. repair
should be made only if the problem
is consistent.
Hydraulic lifter bleed down. Clean, test and @ Excessive crankshaft end clearance. Replace
replace as necessary. crankshaft
thrust bearing.
@ Excessive front main bearing clearance. Replace
worn parts.
KNOCKS AT IDLE HOT
Loose or worn drive belts. Tension and/or @ Excessive piston pin clearance. Ream and install
replace as necessary. oversize pins. (VIN R and 2) or replace piston
A/C Compressor or generator bearing. Replace and
pin.
as necessary.
e Connecting rod alignment. Check and replace
rods as necessary.
Noisy mechanical fuel pump. Replace pump.
8 Insufficient piston to bore clearance. Hone bore
Valve train. Replace parts as necessary. and
fit new piston.
@ Loose crankshaft balancer. Torque and/or
Improper oil viscosity. Install proper viscosity oil
replace worn parts.
for expected temperature4 See Owner" e Piston pin offset to wrong side. Install correct
ENGINE OVERHEATS
Coolant system leak, oil cooler system leak, or
2. Belt slipping or damaged. Replace tensioner, or
coolant recovery system not operating. Check for belt, as required.
leaks and correct as required. Check coolant
3. Thermostat stuck closed. Check and replace if
recovery tank, hose and radiator cap.
required.
4. Electrical cooling fan operation. See the
ELECTRICAL TROUBLESHOOTING
MANUAL.
5. Head gasket leaking. Check and repair as
required.

ENGINE GENERAL INFORMATION 6-5
INSTRUMENT PANEL OIL WARNING LAMP "ON" AT IDLE
1. Oil cooler, or oil or cooler line restricted. Remove 2. Oil pump pressure low. See oil pump repair
restrictions in cooler or cooler line. procedures
in Section
6A.
ENGINE COMPRESSION EST
COMPRESSION TEST
Important
e Disconnect the "BAT." terminal from the - HE1 distributor or ignition module.
To determine if the valves or pistons are at fault,
a test should be made to determine the cylinder
compression pressure. When checking cylinder
compression, the throttle and choke should be open, all
spark plugs removed, and the battery at or near full
charge. The lowest reading cylinder should not be less
than
70% of the highest and no cylinder reading
should be less than
689 kPa (100 PSI). This
should be done with four
"puffs" per
cylinder.
Normal - Compression builds up quickly and
evenly to specified compression on each cylinder.
Piston Rings - Compression low on first
stroke, tends to build up on following strokes, but does
not reach normal. Improves considerably with addition
of oil.
Valves - Low on first stroke, does not tend to
build up on following strokes. Does not improve much
with addition of oil.
Use approximately three squirts from a plunger
type oiler.