Engine Controls - Updated Idle Load Compensator Chart
87olds9NUMBER: 88-T-12
DATE: December 4, 1987
SECTION: 6E1
SUBJECT SERVICE MANUAL REVISION - CHART C-2C
"IDLE LOAD COMPENSATOR (ILC) CHECK"
1986 THROUGH 1988 CUTLASS SUPREME
MODELS/YEARS CUTLASS SUPREME CLASSIC, AND CUSTOM CRUISER MODELS EQUIPPED WITH THE LV2 V-8 (VIN CODE Y) ENGINES
The attached Idle Load Compensator chart replaces the chart in Section 6E1-C2 of the 1986 and 1987 Chassis Service Manuals and the 1988 New Product Service Manual.
The C-2C facing page artwork 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.
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 turned "OFF" when the IGN is "OFF". This traps vacuum to the ILC, keeping the plunger retracted so the engine can shut down without dieseling.
CHART C-2CIDLE LOAD COMPENSATOR (ILC) CHECK 5.0L (VIN Y) (CARB):
Test Description: Numbers below refer to circled numbers on the diagnostic chart.
1. ILC plunger should be extended as no vacuum is being applied.
2. ILC plunger should retract if vacuum is applied.
3. Depressing the TPS should make the ECM turn the ILC quad-driver "ON", blocking vacuum to the ILC, and simulating a W.O.T. condition. Clear long term memory after this procedure, as the ECM must relearn correct TPS voltage.
4. With test terminal grounded, ECM should be turning "ON" ILC solenoid assembly. Test light should be "ON".
5. Anti-diesel solenoid is energized any time ignition is "ON", so test light should be "ON".
6. Test light should be "OFF", as ILC quad-driver should be turned "OFF".
7. If the test light goes out, the ECM has to be replaced, as the quad-driver inside the ECM has failed.