Control and Check Valve

Pulse Air System:

AIR CONTROL VALVE
Remove the air control valve. Blow through the air inlet port. Air should not flow through the valve. Using a external vacuum source apply 15 inches of vacuum to the control valve. Blow through the air inlet port. Air should flow freely through the valve. If either test fails, the valve must be replaced.

Check Valve:

AIR INJECTION CHECK VALVE
The check valve is not repairable, and, if necessary, should be replaced with a new valve. Check valve failure results in excessive exhaust system noise under the hood at idle and hardening of the rubber hose from the check valve to the air control valve. To determine if the check valve is inoperative, disconnect hose from check valve inlet. With the engine idling and the transmission in neutral, the vacuum exhaust pulses can be felt at the check valve inlet. If hot exhaust gas is escaping from the inlet, the check valve is inoperative and must be replaced.