C 1500 Truck 2WD V8-454 7.4L (1990)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
Engine Controls - Exhaust Odor/Detonation
Number:
90-421-6E
Section:
6E
Date:
MAY 1991
Corp. Bulletin No.: 136511
Subject:
DETONATION AND/OR EXHAUST ODOR
Model and Year:
1990 C/K, R/V G AND P TRUCK WITH 7.4L ENGINE
Condition:
Some owners of 1990 trucks with the 7.4L engine may comment of either detonation at highway speeds or exhaust odor (sulfur smell)
at idle.
Cause:
The original spark advance and idle calibration may generate detonation or sulfur odor comments for a few isolated conditions.
Correction:
On trucks where these conditions can not be repaired using normal service procedures, a revised calibration PROM should be installed
(See below).
Part
Emission
PROM
SCANNER
Number
System
Trans.
Broadcast
I.D.
16165446
NA4 (above
M40 (Auto)
AYKK
5451
8600 GVW)
16165447
NA4 (above
M20 (Manual)
AYKL
5461
8600 GVW)
Parts are expected to be available on June 3, 1991. Until then, normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP
orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part
will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in
place.
Note:
These PROMs SHOULD NOT BE USED on the Chevy "S.S."
Labor Operation Number:
T0500
Labor Time:
.6 Hour
Trouble Code:
92
Parts are currently available from GMSPO.
Labor Operation Number:
T0500
Labor Time:
.8 Hours
TROUBLE CODE:
92
