Air Injection: Testing and Inspection

AIR Management Diagnosis:

PFI Emission Circuit:

CIRCUIT DESCRIPTION

The AIR divert and switch solenoids are supplied with 12 volts on circuit 639 from the 19 amp number 3 solenoid fuse on the underhood relay panel. The ECM controls air management by grounding AIR switch solenoid circuit 436 and AIR divert solenoid circuit 429. To divert air to the air cleaner, the divert solenoid is de-energized. When pin E9 at the ECM is grounded, the divert solenoid energizes and diverts air to the switching valve. When the switch solenoid is de-energized the air is routed to the catalytic converter and when pin E6 at the ECM is grounded the air is routed to the exhaust ports.

AIR PUMP DIAGNOSIS

The air pump is a positive displacement vane type which is permanently lubricated and requires no periodic maintenance. DO NOT OIL AIR PUMP! The AIR system is not completely noiseless. Under normal conditions, noise rises in pitch as engine speed increases.

Accelerate engine from idle to approximately 1500 RPM and observe air flow from the hose(s). If air flow increases as engine is accelerated, the pump is operating satisfactorily. If air flow does not increase or is not present, proceed as follows:
1. Inspect for proper drive belt tension.

2. Inspect for a leaky pressure relief valve. Air may be heard leaking with the pump running.

3. Inspect for a seized air injection pump.

4. Inspect hoses, tubes and all connections for leaks and proper routing.

5. Inspect for air flow from control/switching valve.

6. Inspect air injection pump for proper mountion and bolt torque.

7. If no irregularities exist and the air injection pump noise is still excessive, remove and replace pump.