Igntion - Timing Adjustment Alleviates Detonation

85-120
6D
SEPT., 1985
Subject: DETONATION ON 1.6L ENGINES (VIN CODE C)
Model and Year: 1985 CHEVETTE
TO: ALL CHEVROLET DEALERS
Some 1985 Chevettes with 1.6L engines may exhibit detonation. On vehicles where the procedure outlined in the shop manual did not eliminate the detonation, retarding the base engine timing up to 4~ is permissible. Base change timing is now 8~ BTDC. With the maximum recommended timing change, base engine timing will be 4~ BTDC. This change will alleviate the detonation.