ENG. STALL AFTER HOT RESTART COLD START & COLD ENG. HES.
Models 1987 6000 AND 1988 GRAND PRIX Affected: EQUIPPED WITH GEN II - 2.8L ENGINE (VIN CODE W)
Some 1987 6000 models and 1988 Grand Prix models equipped with a 2.8L V-6 engine may experience a cold start stall, a stall after start with a warmed-up engine or a stall during deceleration. A 5-speed manual transmission Sunbird model may also experience a hesitation during acceleration primarily when the engine is cold (ambient temperatures of 40 to 70 degrees Fahrenheit). This hesitation may also be experienced during transmission gear shifts.
A repeated stall after hot restart may be caused by residue accumulating inside the throttle body bore, behind the throttle plate, which limits the air flow past the throttle plate in the idle position. The hesitation concern may be due to a lean Electronic Control Module (ECM) fuel calibration. The cold start stall may be due to a lean ECM calibration, low engine idle speeds, the loss of fuel pressure, or loose electrical connections at the ignition coil and/or the mass airflow sensor.
The aforementioned customer comments may be repaired as follows:
1. Perform normal service procedures as outlined in the service manual for the repair of engine stall or hesitation.
2. Verify that all electrical connections such as at the ignition coil and mass airflow sensor are secure.
NOTICE: LOOSE/POOR ELECTRICAL CONNECTIONS AT ALL SENSORS AND ECM METRI-PAK CONNECTORS CAN BE A PROBLEM ANYWHERE ON THE ENGINE. INTERMITTENT CONNECTION CAN PRODUCE STALLING.
3. Verify that there are no engine vacuum leaks at the manifold absolute pressure (MAP) sensor, positive crankcase ventilation (PCV), exhaust gas recirculation (EGR), or other systems.
4. Verify that the fuel system is functioning properly and has proper fuel pressure (reference bulletin 87-6 (Gasoline) -21).
5. Clean the throttle body bore as specified in bulletin 87-6 (Gasoline) -32.
6. Measure the minimum idle speed and throttle position, and adjust to specification if required (reference bulletin 87-6 (Gasoline) -32).
7. Replace the ECM MEMCAL (see Attachment A), using the following installation procedure:
(a) Disconnect battery power.
(b) Install new ECM MEMCAL calibration.
(c) Reconnect battery power.
(d) Start vehicle with AC/defroster off and power steering not cramped.
(e) Allow vehicle to idle in drive for 6 minutes and until thermostat has opened. This will facilitate learning of base idle.
(f) Return vehicle to service.
NOTICE: IT IS INAPPROPRIATE TO REPLACE THE MEMCAL AND RETURN THE VEHICLE TO THE CUSTOMER WITHOUT PROPERLY COMPLETING THE PREVIOUS SERVICE INSTRUCTIONS (ITEMS 1-6).
Warranty Information
Use applicable labor time and operation numbers.
1987 MODEL YEAR
TRANSAXLE EMISSION SERVICE MODEL TRANSMISSION RATIO/CODE SYSTEM MEMCAL P/N
6000 STE 5-Spd. Man. 3.61 Federal 16087148 6000 SE
6000 Wagon 5-Spd. Man. 3.61 Federal 16087122 6000 3-Spd. Auto. 2.84/7CTC Federal 01228596 6000 LE 6000 3-Spd. Auto. 3.18/7CXC Federal 01228600 6000 LE
6000 STE 3-Spd. Auto. 3.18/7CXc Federal 01228608 6000 4-Spd.Auto. 3.33 Federal 01228604 6000 LE
6000 STE 6000 SE 4-Spd.Auto. 3.33 Federal 01228612 6000 Wagon
6000 SE 5-Spd.Man. 3.61 California 16088713 6000 STE 5-Spd.Man. 3.61 California 16088714 6000 Wagon 6000 3-Spd.Auto. 2.84/7CTC California 01228598 6000 LE 6000 3-Spd.Auto. 3.18/7CXC California 01228602 6000 LE
6000 STE 3-Spd. Auto. 3.18/7CXC California 01228610
6000 4-Spd. Auto 3.33 California 01228606
6000 STE 6000 SE 4-Spd.Auto 3.33 California 01228614 6000 Wagon
1988 MODEL YEAR
Grand Prix 5-Spd. Man. 3.61 Federal 16086995
Grand Prix 4-Spd. Auto. 3.33 Federal 16087003
Grand Prix 5-Spd. Man. 3.61 California 16087007
Grand Prix 4-Spd. Auto. 3.33 California 16087012
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
