G 20 3/4 Ton Van V8-305 5.0L VIN H 4-bbl (1984)
Spark Plug: All Technical Service Bulletins
Ignition - Spark Knock (Pre-Ignition)
Number:
85-169 (REISSUE)
Section:
6D
Date:
FEB., 1986
Subject:
SPARK KNOCK (PRE-IGNITION)
Model and Year: 1984-85 "C-K-G" 10-30 TRUCKS WITH FEDERAL EMISSIONS AND LE9 (305 VIN CODE H), LF3 (3O5 VIN CODE F) AND LS9 (350 VIN CODE L)
TO:
ALL CHEVROLET DEALERS
This revised Dealer Bulletin cancels and replaces 85-169 dated December 1985 which should be destroyed. This reissue reflects
additional engine applications.
Some 1984-85 vehicles equipped with subject V8 engines may experience induced pre-ignition or poor performance when operating
in a loaded condition or pulling a grade. As a result of the pre-ignition, the ESC retards the spark timing, and a noticeable reduction in
performance may occur. In the event the pre-ignition condition is not corrected by the ESC spark retard, continued operation under
these conditions could result in internal engine damage. To reduce the possibility of this occurrence, the spark plugs should be
changed to a colder heat range.
When these conditions exist, the original equipment (R45TS) spark plugs should be replaced with R43CTS (P/N 5613810).The
correct spark plug gap is .045".
