Maximum Isc Extension (Deville & Fleetwood) — Engine Controls - Adjustments - V8 — Adjustments

Maximum Isc Extension (Deville & Fleetwood) Chevrolet Corvette C4

Before adjusting maximum Idle Speed Control (ISC) extension, check minimum idle and Throttle Position Sensor (TPS) adjustment. See MINIMUM IDLE under V8 IDLE SPEED. Also, see THROTTLE POSITION SENSOR (TPS).
With ignition on and engine off, select ISC MOTOR override E.5.3. See ENTERING SELF-DIAGNOSTICS in appropriate G - TESTS W/ CODES article in this section. Fully extend ISC motor by pressing WARMER button on the Electronic Control Center (ECC) on dash. Fuel data center should alternately display E.5.3 and 99, indicating override function has started.
ISC should extend to maximum extend position. With ISC at maximum extended position, TPS voltage should be 1.15-1.20 volts. If TPS voltage is NOT 1.15-1.20 volts, adjust ISC plunger. Adjust ISC plunger, clockwise or counterclockwise, until TPS parameter reads 1.18 volts.
Recheck maximum extend setting. Press COOLER button to retract ISC plunger. Wait 5 seconds. Press WARMER button and check TPS voltage. Readjust ISC plunger if necessary.

Maximum Isc Extension (Deville & Fleetwood) Chevrolet Corvette C4