Idle Control System
- Check operation of air regulator with cold engine. Start engine. Engine idle speed should be higher than normal after initial start. If idle speed is not higher, go to step 5).
- As engine warms-up engine idle speed should stabilize. Check air regulator for leakage. Disconnect hose between air regulator and throttle valve body at throttle valve body side. Plug throttle body fitting end. See Fig 1
.
- Determine if air regulator valve is functioning properly. Start engine. Check for variation in engine speed by closing and opening end of air regulator hose. Variation in engine speed should be less than 50 RPM.
- If variation in engine speed is more than specification, replace air regulator valve.
- If fast idle speed was not higher than normal on initial engine start, disconnect air regulator harness connector.
- Using an ohmmeter, measure resistance between air regulator terminals. Resistance should be 38-42 ohms at room temperature. If resistance is not within specification, replace air regulator. If resistance is within specification, go to next step.
- Turn ignition switch to the "ON" position. Using a voltmeter, check for voltage at air regulator harness connector.
- If voltage is present, replace air regulator. If voltage is not present, check wiring leading to air regulator and repair as required. Also, check fuel pump relay and replace if defective.
Courtesy of ISUZU MOTOR CO.