DIAGNOSTIC PROCEDURE COLD STARTABILITY REPAIR

MODELS AFFECTED: 1983-84 SKYHAWKS EQUIPPED WITH 2.0L ENGINE (VIN CODE P) AUTOMATIC TRANSMISSION AND FEDERAL EMISSIONS SYSTEMS

On vehicles repaired per cold startability (reference Buick Dealer Service Bulletin 84-6E-30B), normal check engine light procedures for trouble code 42 will no longer apply. This trouble code can no longer be set on these vehicles. On vehicles exhibiting the listed driveability conditions perform the following.

CONDITION

Engine cranks but will not run or engine starts but immediately stops.

Disconnect "set timing" connector. If engine starts see code chart 42 for open or short to ground in EST CKT 423.

Hard start -10 DEG F (-23 DEG C) may hear metallic "knock" during crank.

Check:

- Open circuit 906 - Open relay ground - Faulty relay (will not close during crank)

Spark knock heavy loads, loss of performance and fuel economy

Check and note timing. Disconnect "set timing" connector and again note timing. No change check: Open or short to ground in bypass CKT 424, See code 42 - Relay contacts stuck closed

If the above procedures do not repair the condition, then the cold start repairs are not the cause and normal diagnositc procedures should be used.

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.