Engine Controls - Driveability, Hesitation, Sag or Surge
87chevy04Number: 85-217
Section: 6E
Date: JAN., 1987
Subject: HESITATION, SAG OR SURGE-ENGINE DRIVEABILITY CONDITIONS
Model and Year: 1985 SPECTRUM
TO: ALL CHEVROLET DEALERS
Some of the subject vehicles may experience engine driveability complaints of hesitation or sag when operating under cold engine conditions and surge at warm engine operating temperatures.
In order to effect an improvement, a revised ECM was introduced. Complaint vehicles can be corrected using this ECM per the following information:
AUTOMATIC TRANSMISSION - VIN prior to F8421857
Use controller - ECM P/N 1227077, with calibrator 1227729
VIN F8421857 and later: Replace existing PROM with
calibrator, 1227729.
MANUAL TRANSMISSION - VIN prior to F8422417
Use controller - ECM P/N 1227077, with calibrator 16051549
VIN F8422417 and later: No additional correction needed.
Current Accelerator Pump Linkage:
New Accelerator Pump Linkage:
To further improve engine driveability on automatic
transmission cars, the following part should also be
obtained from GMSPO and installed: pump arm
kit-accelerator, P/N 94426520 as shown in illustration.
Use existing labor time.
Current Accelerator Pump Linkage:
New Accelerator Pump Linkage:
ACCELERATOR PUMP LINKAGE REPLACEMENT
1. Move air cleaner forward about 7" (remove vacuum hoses as required).
2. Replace accelerator pump linkage. See illustration.