Engine Controls - MIL ON, DTC's Set, Poor Driveability
Number 86-6(Gasoline)-66 Date 10/86Subject: ENGINE CALIBRATION CHANGE: TO IMPROVE DRIVEABILITY AND ELIMINATE FALSE "SERVICE ENGINE SOON" LIGHTS
1986 FIREBIRD VEHICLES WITH 5.0L LB9 TPI ENGINE (ENGINE CODE F)
New service calibrators (Ref: Called Mem-Cal In Shop Manual) have been released for the 1986 Firebirds with the 5.0L TPI engine. These new calibrators will address the following customer comments:
1. "Rough Idle" on both hot and cold engine - the idle speed is raised to 650 plus or minus 50 RPM.
2. "Chuggle or Shudder" at low speeds - torque converter clutch (TCC) engagement speed is raised to 41 MPH.
3. "Hesitation" on light acceleration with a hot engine.
4 . "Cold Driveability" - New calibration eliminates light to moderate
sag on cold driveaway.
5. "Service Engine Soon" Lights - Eliminates the following false Codes:
A. Code 32 - EGR System Failure
B. Code 33 - Mass Airflow Sensor Voltage High
C. Code 34 - Mass Airflow Sensor Voltage Low
D. Code 43 - Electronic Spark Control
E. Code 44 - Lean Exhaust Indication
If normal engine diagnostics and repair do not correct the above conditions, it will be necessary to replace the calibrator in the ECM. Below is a listing of the new calibrators and their usages.
ON AIR CONDITIONING (C-60) FIREBIRDS
With QYZ (P215/65 R 15/N 15" Tire) Use - 1228290 Calibrator
With QAC (P235/60 VR 15N Tire) Use - 1228291 Calibrator
With QDZ (P245/50 VR 16N Tire) Use - 1228291 Calibrator
ON NON-AIR CONDITIONING (C-41) FIREBIRDS
With QYZ (P215/65 R 15/N 15" Tire) Use - 1228292 Calibrator
With QAC (P235/60 VR 15N Tire) Use - 1228293 Calibrator
With QDZ (P245/50 VR 16N Tire) Use - 1228293 Calibrator
Use Applicable Labor Time and Operation Numbers.