Engine - Surge/Hesitation/Stalls/Idle Fluctuation

BULLETIN NO.: 94-T-15

DATE: April, 1994

GROUP/SEQ. NO.: Engine-06

CORPORATION NO.: 486001

SUBJECT:
Engine Stalls After Initial Start/Hesitates During Launch/Surges During Light Acceleration, or Has Increased, and/or Fluctuating Idle that is More Pronounced with A/C On (Install New PCM Calibration)

Due to additional subject information and a revised procedure, this bulletin cancels and supercedes (with a new bulletin number) bulletin 92-T-35 (Corporation No. 286503), which should be discarded.

MODELS AFFECTED:
1992 Saturns with DOHC (LLO) engines.

CONDITION:
Some customers of 1992 Saturns, equipped with DOHC (LLO) engines may comment that the engine exhibits one or more of the following conditions:

^ Engine stalls after initial start.
^ Hesitates during launch.
^ Surges during light acceleration.
^ Increased and/or fluctuating idle that is more pronounced with the A/C On.

CAUSE:
Due to engine sensitivity to variations in cool ambient temperatures along with the 1992 Federal regulations addressing Spring and Summer fuel grade volatility, initial start-up and warm-up driveability has been impacted.

CORRECTION:
Verify that one or more of the conditions listed above exist.

If any of these conditions exist, proceed with the steps listed under "PROCEDURE".

PROCEDURE:

1. Use the Scan tool, to check for PCM/EC or PCM/TC diagnostic trouble codes and information flags. If no diagnostic trouble codes or information flags are present go to step 2. If diagnostic trouble codes and/or information flags are present, refer to the appropriate chart in the "Electronic Engine Controls" or "Automatic Transaxle" Service Manuals, and repair the condition. After verifying that all diagnostic trouble codes and/or information flags have been repaired, refer to step 2.

2. If no diagnostic trouble codes or information flags are present or have been repaired, monitor Scan tool data and verify that all parameters are within specification. (Refer to "Scan Tool General Information Table" in the "Electronic Engine Controls Service Manual.") If parameters are not within specification, repair the condition. After verifying that all parameters are within specification, refer to step 3.

3. Download the new calibration, using the Service Stall System (SSS). (Refer to "Service Stall System User Guide" or "Electronic Engine Controls Service Manual" for download instructions.)

IMPORTANT:
Before installing a new calibration, make a note of the transaxle calibration installed, and download the same transaxle calibration with the correct engine calibration.





IMPORTANT:
Verify that the concern has been repaired. If problem still exists, refer to diagnostic procedures in the "Fuel/Air Intake/Exhaust Service Manual," and/or "Electronic Engine Controls Service Manual."

CLAIM INFORMATION:





To receive credit for this repair, submit a claim through the Saturn Dealer System as follows: