G 3500 1 Ton Van V8-454 7.4L VIN N TBI (1995)
Engine Speed Governor System: Adjustments
Idle Speed Control Actuator Adjustment
PROCEDURE
1. Before adjusting ISC actuator you must first check the minimum idle speed to be 625 RPM +/-25 (In Drive, system in "Closed Loop").
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ISC actuator must have vacuum applied so that it is not contacting the throttle lever. See image VIEW A.
2. Remove vacuum hose on ISC actuator on warm engine.
3. Adjust ISC actuated idle speed to 1300 +/- 50 RPM. See image VIEW B.
4. Install vacuum hose.