Caprice Wagon V8-305 5.0L (1986)
Hot Idle Compensator (Non Comp. Controlled): Technical Service Bulletins
Idle Load Compensator (ILC) - Manual revision
Number:
87-254-6E
Section:
6E
Date:
Dec., 1987
Subject:
SERVICE MANUAL REVISION IDLE LOAD COMPENSATOR (ILC) CHECK FOR 5.0L (VIN CODE Y) ENGINE
Model and Year:
1986-87 CAPRICE WAGON
TO:
ALL CHEVROLET DEALERS
The attached information replaced the 1986 and 1987 Service Manual information published in the service manuals.
The chart C-2C has been changed to show all the components between the ILC/RVB/EGR solenoid assembly and idle load compensator. The C-2C
diagnostic chart has been reworked to more thoroughly diagnose any failure of components within the ILC vacuum and electrical system.
Please replace the original charts with the ones supplied in this bulletin.
CHART C-2C
IDLE LOAD COMPENSATOR (ILC) CHECK 5.0L (VIN Y) (CARB)
Circuit Description:
The idle load compensator (ILC) is mounted on the carburetor and is used to control various low engine rpm conditions. The ILC uses a spring loaded
vacuum sensitive diaphragm whose plunger extends when vacuum is not present. Vacuum to the ILC is controlled by the ECM through the ILC/RVB/
EGR solenoid assembly. When the ECM turns "ON" the ILC solenoid assembly, vacuum is cut "OFF" to the ILC. Vacuum is regulated through the VRV
and delayed under high load conditions (checked) by the DVDV and through the Anti-diesel solenoid (ADS). The ADS is energized when the IGN is
turned "ON", allowing vacuum to the ILC, and "OFF" when the IGN is "OFF". This supplies vacuum to the ILC, keeping the plunger retracted so the
engine can shut down without dieseling.
