Functional Check Procedure 7A1-5; Preliminary Checking Procedure 7A1-5; External Controls 7A1-5; T„V. Cable System Diagnosis - Pontiac Fiero 1988 Service Manual

ON-VEHICLE
SERVICE
7A1-5
— Bushing moved forward and dam-
aged
— Garter spring missing from seal
• Converter leak in weld area.
• Case or drive sprocket support.
• Turbine shaft oil seal worn or damaged.
4. Fluid comes out vent pipe or fill tube:
• Over-filled
• Coolant in fluid
• Case porous
• Incorrect dipstick
• Plugged vent
• Drain back holes plugged
TORQUE CONVERTER CLUTCH (TCC)
DIAGNOSIS
The TCC is applied by fluid pressure which is
controlled by a solenoid located inside the automatic
transaxle assembly. The solenoid is energized or
released by making or breaking ground contact thru a
combination of external switches and sensors.
TCC Diagnosis
• For electrical diagnosis of TCC, refer to the spe-
cific carline section in Section 8A, Electrical
Diagnosis.
• For diagnosis of emission control related compo-
nents of TCC, refer to Section 6E.
• For diagnosis of TCC Hydraulic controls, refer
to Hydraulic Diagnosis.
Functional Check Procedure
[jy| Inspect
1. Install a tachometer.
2. Operate the vehicle until proper operating tem-
perature is reached.
3. Drive vehicle at
50-55
mph
(80-88
km/h) with
light throttle.
4. Lightly touch the brake pedal and check for
slight bump when the TCC releases a slight
increase in engine RPM.
5. Release the brake and check for a re-apply of
the converter clutch and a slight decrease in
engine RPM.
Preliminary Checking Procedure
The purpose of the preliminary checking proce-
dure is to isolate external (electrical) problems from
internal (electrical or mechanical) ones. Refer to
"General Service Procedures" for individual compo
nent test procedures.
U]
Important
• Use only a scale type ohmmeter. High
impediance type ohmmeters and those
with a digital readout will not work.
• An ALCL scanner may be used to verify
the ground path. Remember, a completed
ground does not indicate that a circuit
carries current.
- Do not bench test using an automotive
type battery. Accidentally crossed wires
will destroy the internal diodes of the
TCC solenoid.
External Controls
[Tl Important
• Connect voltmeter between transmission
connector and ground.
• Turn key "On".
• If 12 volts are present at the connector,
refer to the Hydraulic Diagnosis.
• If 0 or low voltage is found, refer to Sec-
tions 6E and 8A for electrical diagnosis.
T.V. CABLE S Y S T E M DIAGNOSIS
[ y j Inspect
CAUTION- To avoid possible personal
injury and/or damage to the car, brakes
must be applied at all times during the
test.
1. Install line pressure gage.
2. Install engine tachometer.
3. Warm up engine to proper operating
temperature.
4. Run engine at 1000 RPM.
5. Apply parking brake.
6. Place gear selector in "Park" and note oil
pressure.
7. Place gear selector in "Drive". Oil pressure
should be equal or not more than 10 psi (34 kPa)
higher than in "Park".
8. Increase engine speed to 1400 RPM. If oil pres-
sure does not increase, adjust T.V. cable.
NOISE AND VIBRATION DIAGNOSIS
1. Vibration with car in motion.
Iffl
Inspect
• Engine and transmission mounts damaged
or loose. Refer to Sections 6A, 7A, and
7A1.
• Tires out of balance or unevenly worn.
Snow tires, mixed sizes or mixed radial
and bias ply. Refer to Section 3E.