1988 PONTIAC FIERO Service Repair Manual

EXHAUST SYSTEM 6F-1
SEC"B0N 6F
EXHAUST SYSTEM
CAUTION: Exhaust system components should avoid overheating and possible damage to the
have enough clearance from the underbody to passenger compartment carpets.
................................. General Description 6F- 1 Hanger ............................................................ 6F- I
..................... ....................... Exhaust Pipe .. 6F- I Clamp ............................................................ 6F- I
Muffler .......................................................... 6F- 1 Catalytic Converter ......................................... 6F- 1
.......................... Resonator ........................... .. 6F- 1
GENERAL DESGRIP"F0N
When inspecting or replacing exhaust system
components, make sure there is adequate clearance
from all points on the underbody to avoid possible
overheating of the floor pan and possible damage to the
passenger compartment insulation and trim materials.
Check complete exhaust system and nearby body
areas and trunk lid for broken, damaged, missing or
mispositioned parts, open seams, holes, loose
connections or other deterioration which could permit
exhaust fumes to seep into the trunk or passenger
compartment. Dust or water in the trunk may be an
indication of a problem in one of these areas. Any
defects should be corrected immediately. To help
insure continued integrity, the exhaust system pipe
qever a
rearward of the muffler must be replaced whe.-
new muffler is installed.
EXHAUST PlPE
The exhaust manifold to crossover pipe
connections are of the ball type, thus eliminating the
need for gaskets.
MUFFLER
The mufflers are a tri-flow design. Some muffler
installations have a slot in the inlet and/or outlet pipe
which indexes to a key (tab) welded on the exhaust
and/or tail pipe to help maintain alignment.
RESONATOR
A resonator is used on some series exhaust
systems. It allows the use of mufflers with less back
pressure and provides for optimum tuning
characteristics of the exhaust system. The
installation of exhaust system supports is
very important as improperly installed supports can
cause annoying vibrations which are difficult to
diagnose.
CLAMP
Two methods are used for connecting exhaust
system slip joins, (1) clamp and
(2) weld. When
servicing a welded connection it should be cut and the
new connection clamped when installing replacement
parts. Also, coat slip joints with exhaust system sealer
before assembling (Fig. 1).
SLOT IN PlPE
9/16 EXH. CROSSOVER TO EXH. PlPE 318 REMAINING JOINTS
EXHAUST SYSTEM U-BOLT CLAMPS
POSITION CLAMP AS SHOWN IN RELATION TO SLOT TO PREVENT GAS LEAKS ,,ooo,.,,
Fig. 1 Installation of Exhaust System Clamp
CATALYTIC CONVERTER
The catalytic converter is an emission control
device added to the exhaust system to reduce
pollutants from the exhaust gas stream.
NOTICE: THE CATALYTIC CONVERTER
REQUIRES THE USE OF UNLEADED FUEL
ONLY.
HANGER Periodic maintenance of the exhaust system is not
T~~ types of hangers are used to support the required, however, if the car is raised for other service,
exhaust system. one type is a conventional rubber it is advisable to check the general condition of the
strap and the second type is a "rubber block." The catalytic converter, pipes and mufflers.
rubber block type provides a rigid hanger along with Three
different converter designs are used in
a feature that continues to support the exhaust system combination with two different types of catalyst.
in the event a rubber insulator block is broken. Converter Designs:

6F-2 EXHAUST SYSTEM
, 1 -AIR MANAGEMENT SVSTEM 6- REAR BED
7-THREE-WAY
3-METAL
MESH 8-FRONT BED
5-OXIDATION
Fig. 2 Dual Bed Monolith
Dual Bed Monolith
Single Bed Pellet
Dual Bed Pellet
Catalyst Types:
Oxidation Catalyst
Three-Way (Reduction) Catalyst
1 - INSULATION 8- INLET GAS
2- OUTER WRAP 9- CATALYTIC PELLET
3- CONVERTER SHELL
. COMPoIJND
4- CATALYST 10- OUTLET
5- INSULATION
6- BED SUPPORT
Fig. 3 Single Bed Pellet
The oxidation catalyst is coated with a catalytic
material containing platinum and palladium which
lowers levels of hydrocarbon (HC) and carbon
monoxide (CO). The catalyst coating on the three-way
(reduction) catalyst contains platium and rhodium
which lowers levels of oxide of nitrogen (NOX) as well
as hydrocarbons (HC) and carbon monoxide
(CO).
2- OUTLET 7- INSULATION I 3- OXIDATION CATALYST 8- FlLL PLUG I 4- INLET 9- INSULATION L
5- RETAINER 10- AIR PLENUM
11- AIR INLET 12- FILL PLUG
(AIR MANAGEMENT SYSTEM)
5200W8F
Fig. 4 Dual Bed Pellet

EXHAUST SYSTEM 6F-3
1. MANIFOLD 8. INTERMEDIATE EXHAUST 13. CONVERTER ASSEMBLY 2. SEAL PIPE ASSEMBLY 14. 60 Nvrn (44 LBS. FT.)
3. CROSSOVER PIPE 9. 50 N-rn (37 LBS. FT.) 15. FRONT EXHAUST 4. 20 N-m (15 LBS. FT.) 10. HANGER PIPE
5. UNDERBODY 11. INNER BRACKET
6. 10 N-m (8 LBS. FT.) ASSEMBLY
7. MUFFLER 12. TRANSMISSION
J10001-6F-F
Fig. 5 Exhaust System - V.I.N. S

1. UNDERBODY
2. 10
N.rn (8 LBS. FT.)
3. MUFFLER
4. INTERMEDIATE EXHAUST
5. 60 Nern (44 FT. LBS.)
6. CONVERTER ASSEMBLY
7. 20
N-rn (15 FT. LBS.)
8. 50 N-rn (37 LBS. FT.)
9. TRANSMISSION
10. FRONT EXHAUST
PlPE
11. MANIFOLD
12. CROSSOVER
PlPE
13. SPACER
Fig. 6 Exhaust System - V.I.N. F, E and 8

HYDRAULIC DIAGNOSIS 700.R4-1
SECTION 700-R4
AUTOMAT C TRANSM
CONTENTS
GENERAL DESCRIPTION
The THM 700-R4 is a fully automatic
transmission for rear wheel drive vehicles which
provides four forward gear ranges and a reverse.
The major components of this transmission are:
e Torque Converter Clutch Asm.
e Vane Type Oil Pump
e 2-4 Band Asm.
e Five Multiple Disc Clutches
0 Two Planetary Gear Sets
0 One Sprag Clutch
0 One Roller Clutch
e Valve Body Asm.
The oil pressure and shift points are controlled by
throttle opening via a throttle valve cable. (See Section
7A1 for T.V. cable information).
The transmission can be operated in any one of
the following seven modes:
P
- Park position prevents the vehicle from rolling
either forward or backward. (For safety reasons the
parking brake should be used in addition to the park
position).

700-R4-2 HYDRAULIC DIAGNOSIS
R - Reverse allows the vehicle to be operated in
a rearward direction.
N - Neutral allows the engine to be started and
operated without driving the vehicle. If necessary this
position may be selected if the engine must be restarted
with the vehicle moving.
D - Overdrive is used for all normal driving
conditions. It provides four gear ratios plus converter
clutch operation. Downshifts are available for safe
passing by depressing the accelerator.
D - Drive position is used for city traffic, hilly
terrain, and trailer towing. It provides three gear
ranges. Again, downshifts are available by depressing
the accelerator.
2 - Manual second is used to provide acceleration
and engine braking. This range may be selected at any
vehicle speed.
1 - Manual Lo is used to provide maximum
engine
brlking. This range may also be selected at any
vehicle speed.
DIAGNOSIS INFORMATION
ROAD TEST PROCEDURE
e Perform the road test following the sequence
given
e MPH (KPH) shift points will vary with actual
throttle position and driver habits
e Compare the results of the test with speed shift
chart information. Use these results with the
diagnosis information contained in this
Automatic Transmission Hydraulic Diagnosis
Section to evaluate the transmission.
e This test should only be performed when traffic
and road conditions permit
e Observe all traffic safety regulations
Drive and Reverse Engagement Shift Check
1. Start engine
2. Depress brake pedal
3. Move gear selector:
- "Park" (P) to "Reverse" (R)
- "Reverse" (R) to "Neutral"
(N) to "Drive" (D)
Gear selections should be immediate and
not harsh.
Upshifts and Torque Converter Clutch (TCC)
Apply (Figure
2)
With gear selector in "Overdrive" (D)
1. Accelerate using a steady increasing throttle
pressure
2. Note the shift speed point gear engagements for:
- 2nd gear
- 3rd gear
- Overdrive
3. Note the speed shift point for TCC apply. This
should occur while in third gear or overdrive. If
the apply is not noticed, refer to the Preliminary
Torque Converter Clutch Diagnosis information
contained in this section of the Service Manual.
Important
The torque converter clutch will not engage if
engine coolant has not reached a minimum
operating temperature of approximately 54°C
(1 30°F).
Part Throttle Downshift
At vehicle speeds of 40-55 MPH (64-88
KPH) quickly depressed the accelerator to
a half open position and observe:
- TCC releases
- Transmission downshift to 3rd gear
immediately
Full Throttle (Detent) Downshift
At vehicle speeds of 48-55 MPH (77-88
KPH) quickly depress the accelerator to a
wide open position and observe:
- TCC releases
- Transmission downshifts to 2nd gear
immediately
Manual Downshift
1. At vehicle speeds of 40-55 MPH (64 to 88 KPH)
release the accelerator pedal while moving the
gear selector to "Third" gear (D) and observe:
- TCC release
- Transmission downshift to 3rd gear should
be immediate
- Engine should slow vehicle down
2. Move gear selector to "Overdrive" and accelerate
to 40-45 MPH (64-72 KPH). Release the
accelerator pedal while moving the gear selector
to "Second" gear (2) and observe.
- TCC release
- Downshift to second gear should be
immediate
- Engine should slow vehicle down
3. Move gear selector to "Overdrive" (D) and
accelerate to 25 MPH (40 KPH). Release the
accelerator pedal while moving the gear selector
to "First" gear (1) and observe:
- TCC release
- Transmission downshift to 1st gear should
be immediate
- Engine should slow vehicle down
Coastdown Downshift
1. With the gear selector in "Overdrive" (D)
accelerate to 4th gear with TCC applied.
2. Release the accelerator pedal and lightly apply
the brakes to observe:
- TCC release
- Shift points for downshifts.
Manual Gear Range Selection
MANUAL THIRD (D)
1. With vehicle stopped, place gear selector in
"Third" (D) and accelerate to observe:

HYDRAULIC DIAGNOSIS 700434-3
- The first to second gear shift point
- The second to third gear shift point
MANUAL SECOND (2)
2. With vehicle stopped, place gear selector in
"Second" (2) and accelerate to observe:
- The first to second gear shift point
3. Accelerate to 25 MPH (40 KPH) and observe:
- That a second to third gear shift does not
occur
- That TCC does not engage
MANUAL FIRST (I)
1. With vehicle stopped, place gear selector in
"First" (1) and accelerate to 15 MPH (24
KPH)
and observe:
- That no uoshift occurs
- That TCC does
REVERSE
1. With
vehicle stopped, place gear selector in
"Reverse" (R) and slowly accelerate to observe
reverse gear operation.
All possible throttle positions and corresponding
MPH shift point information has not been
provided.
TRANSMISSION PRESSURE CHECK
PROCEDURE
Inspect
e Fluid level
e TV cable adjustment
e Manual linkage
e Engine mechanical, emissions, electrical and fuel
delivery systems
not engage
Install or Connect (Figure 3)
a Oil pressure gage
a Tachometer