COLD START STALL/HESITATION NEW INTAKE MANIFOLD AND CALIB.
SUBJECT: COLD START STALL/HESITATION (NEW INTAKE MANIFOLD AND ENGINE CALIBRATION)
MODELS AFFECTED: 1989-91 SUNBIRD W/2.OL ENGINE (RPO LT2) AUTOMATIC ONLY
This bulletin has been revised to show that the PROM is only f or automatics. This bulletin cancels and replaces bulletin 91-6-61.
Condition: Some owners of 1989-91 Sunbird models with 2.OL engines may experience cold engine start and stall or hesitation.
Cause: The intake manifold does not give even distribution of the air-fuel mixture across all four cylinders . This causes the #1 and #4 cylinders to run lean and the #3 cylinder to run rich.
Correction: Install new intake manifold assembly and calibration PROM.
The part number for the kit is #10217463. This includes all necessary gaskets, calibration PROM and the intake manifold assembly.
Parts are currently available from GMSPO.
INSTALLATION INSTRUCTIONS:
REMOVE OR DISCONNECT
1. Air Cleaner 2. Drain Coolant 3. Serpentine belt. 4. Generator and bracket assembly at camshaft carrier. 5. Power steering bracket at intake manifold. 6. Power steering pump and tensioner bracket assembly lay aside. 7. Ignition coil and bracket assembly from camshaft carrier. 8. Throttle cable bracket from intake manifold bracket. 9. Throttle and T.V. cables from TBI. 10. Throttle cam bracket. 11. Wiring from TBI. 12. Hose, vacuum brake at fitting, cruise control and canister purge, at pipe and PCV at camshaft carrier cover. 13. Fuel lines, inlet and return where hose connects to pipe below brake booster. 14. Hoses, coolant, at:
- Water pump and intake manifold. - Inlet tube to water pump.
15. Intake manifold. 16. TBI with fuel and vacuum lines from intake manifold. 17. EGR valve from intake manifold. 18. Studs from intake manifold. 19. Coolant outlet nipple.
CLEAN -
1. Cylinder head, mating surface. 2. EGR, mating surface. 3. TBI, mating surface for intake and air cleaner.
INSTALL OR CONNECT -
1. Coolant outlet nipple to intake manifold. 2. Studs to intake manifold. 3. EGR valve to intake manifold with new gasket. 4. TBI with fuel and vacuum lines to intake manifold with new gasket
IMPORTANT: Do NOT transfer drop tube to new intake manifold.
5. Intake manifold assembly with new gasket. 6. Retaining nuts and washers. Torque to 22 N.m (16 lb.ft). 7. Hoses, coolant, at:
- Water pump and intake manifold. - Inlet tube to water pump.
8. Fuel lines, inlet and return. 9. Hose, vacuum brake, cruise control, canister purge and PCV. 10. Wiring at TBI. 11. Throttle cam bracket. Install transmission dipstick tube below spacer. 12. Throttle and T.V. cables to TBI. 13. Throttle cable at intake manifold. 14. Ignition coil and bracket assembly at camshaft carrier. 15. Power steering pump and tensioner bracket assembly. 16. Power steering bracket at intake manifold. 17. Generator and bracket assembly at camshaft carrier. 18. Serpentine belt. 19. Adjust T.V. cable if necessary. 20. Fill coolant. 21. Air cleaner.
FOR AUTOMATICS ONLY REMOVE OR DISCONNECT -
1. Right hush panel. 2. ECM mounting nuts and lower ECM. 3. Access cover from ECM. 4. PROM
NOTICE: USE PROM REMOVAL TOOL TO REMOVE PROM FROM SOCKET. OTHERWISE DAMAGE TO THE PROM OR SOCKET MAY RESULT.
INSTALL OR CONNECT -
1. New PROM into socket. 2. ECM access cover. 3. Raise ECM and install mounting nuts. 4. Install hush panel.
FUNCTIONAL CHECK -
1. Turn ignition "ON". 2. Enter diagnostic mode by grounding diagnostic test terminal in ALDL connector. A. Allow Code 12 to flash four times to verify no other codes are present. This indicates that the PROM is installed properly and the ECM is functioning.
B. If trouble Code 51 occurs or if the "Service Engine Soon" light is on constantly with no codes, the PROM is not fully seated or is defective. If not fully seated, press firmly on the ends of the PROM carrier. If it is necessary to remove the PROM, follow the previous removal instructions.
Labor Operation Number: T1813 Labor Time: 3.1 Hours A/T 2.6 Hours M/T
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.
