Air Injection Pump: Testing and Inspection

1. Accelerate engine to approximately 1500 RPM and observe air flow from hose. If air flow increases as engine is accelerated, the pump is operating satisfactorily. If not proceed as follows:
2. Check for proper drive belt tension.
3. Check for leaky pressure relief valve. Air may be heard leaking with the pump running. The air pump is not completely noiseless. Under normal operating conditions, the noise from the pump rises in pitch as engine speed is increased. To determine if excessive noise is the fault of the system, operate the engine with the pump drive belt removed.
4. If excessive noise does not exist with pump drive belt removed, proceed as follows:
5. Check for proper installation of the relief valve silencer, if equipped.
6. Check for a seized air injection pump.
7. Check hoses, tubes and all connections for leaks and proper mounting.
8. Check air injection pump for proper mounting.
9. On vehicles equipped with C3 or C4 systems, perform air management systems check as outlined under ``Air Management Systems.''
10. Replace air injection pump, if defective.