Engine - Cold Startability Diagnostic Supplement
REISSUE84-253
6E
JUNE, 1985
Subject: DIAGNOSTICS FOR COLD STARTABILITY REPAIR (REFERENCE BULLETIN 84-221)
Model and Year: 1983-84 CAVALIER WITH 2.0L ENGINE (VIN CODE P), AUTOMATIC TRANSMISSION AND FEDERAL EMISSIONS SYSTEMS
TO: ALL CHEVROLET DEALERS
This cancels and replaces Chevrolet Dealer Service Bulletin 84-253 dated May, 1985. The reissue clarifies the procedure to be used when diagnosing Cavaliers for cold startability.
83-84 Cold Start Modification:
On vehicles repaired per cold startability (reference Chevrolet Dealer Service Bulletin 84-221), 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:
DIAGNOSTIC SUPPLEMENT
83-84 Vehicles With Cold Startability
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~F(-23~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 diagnostic procedures should be used.