Fleetwood Brougham V8-350 5.7L (1991)
Throttle Position Sensor: All Technical Service Bulletins
Engine - Stalling On Coast Down
Bulletin No.: T-91-81
File in Group: 6E
Number: 86
Corp. Ref. No.: 016540
Date: May, 1991
SUBJECT:
ENGINE STALLING ON COAST DOWN AND/OR ECM
CODES E22, E26, E32, E55, OR E85
MODELS AFFECTED:
1990-1991 DE VILLES, FLEETWOODS, ELDORADOS, AND SEVILLES
Some 1990-1991 DeVilles, Fleetwoods, Eldorados, and Sevilles may experience a stall on coast down with an immediate restart. This condition may be
accompanied by an ECM code E22, E26, E32, E55, or E85. This may be caused by an erratic signal from the Throttle Position Sensor (TPS).
To repair this condition use the following procedure:
1.
Perform trouble code diagnosis. Refer to Section 8D1 of the appropriate Service Information Manual.
2.
Clean engine grounds per Service Bulletin T-90-55.
3.
Inspect the ISC harness behind the generator and the TPS wires for chafing, cuts, or poor connections and repair if necessary.
4.
Check brake switch and throttle switch operation using vehicle on-board diagnostics.
5.
Clean carbon deposits from the throttle blades and bores using a soft bristle brush (i.e., toothbrush) and GM top engine cleaner, P/N 1052626, or
AC-Delco carburetor tune-up conditioner, P/N X66-P, or equivalent. Parts are currently available from GMSPO.
IMPORTANT:
Do not use any solvent that contains methyl ethyl ketone.
6.
Replace the TPS. Refer to Section 6E-C2 of the appropriate Service Information Manual.
7.
Verify base timing is at 10~ BTDC or 6~ if regular unleaded fuel is being used.
NOTE:
The generator must be disabled when performing steps 8 and 9. To disable the generator on a DeVille or Fleetwood ground the green
generator disable lead. The generator is automatically disabled on an Eldorado or Seville by the ECM during the ISC override.
8.
Adjust Minimum Air per Section 6E-C2 of the appropriate Service Information Manual making sure that the ISC harness is disconnected when the
ISC is fully retracted.
9.
Adjust TPS and ISC Maximum Extension per Section 6E-C2 of the appropriate Service Information Manual.
NOTE:
On DeVilles and Fleetwoods, TPS jumper harness tool J-38490 and a DVM must be used to properly set the TPS.
10.
Perform idle learn:
^
Start the engine.
^
On a 1990 vehicle allow the vehicle to idle continuously for 18 minutes.
^
On a 1991 vehicle allow the vehicle to idle continuously for 13 minutes.
^
Place the transmission in drive with the brakes applied.
^
Place the vehicle climate control in the OFF position, and allow the engine to remain at idle for at least one minute.
^
Make sure the outside air temperature reading is at least 50~F.
^
Place the vehicle climate control in the AUTO position, verify A/C clutch engagement, and allow the engine to remain at idle for at least one
minute.
