Air Injection Pump: Testing and Inspection

Air Pump Volume Test

1. Remove rubber cover from pressure relief valve and make sure blue calibrating spacer is present.

2. Disconnect air supply hose from air injection valve.

3. Start engine and check air flow from disconnected hose. At idle air flow should be present and pressure relief valve should remain closed.

4. Slowly increase engine RPM. Air flow should increase. At higher RPM, pressure relief valve should open, closing when engine RPM is reduced.

Air Pump Noise Diagnosis

Normal air pump noise rises in pitch as engine RPM is increased. If air pump is suspected of making excessive noise, isolate problem as follows:

1. Connect tachometer to engine.

2. Start engine and determine RPM at which noise is greatest.

3. Stop engine and remove air pump drive belt.

4. Start engine and run at RPM where noise was greatest. Engine should he run for long periods of time with pump disconnected. If noise is eliminated, replace pump.