Air Control Valve (Switch-Relief)
- Disconnect air supply hose at inlet. Accelerate engine speed to 1500 RPM, and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
- Carefully disconnect air supply hoses at outlets "A" and "B". See Fig 1. Carefully remove vacuum line at vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
- Connect a vacuum line from manifold vacuum fitting to air control valve vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
- If conditions in steps 2) and 3) are not met, replace air control valve. If valve operates satisfactorily, air control valve is okay.