Air Injection: Testing and Inspection

Air Pump Diagnosis:

DIAGNOSIS


AIR SWITCH/RELIEF VALVE TEST

Apply 10 inches Hg vacuum to the air switch/relief valve. If air injection is not upstream, in the exhaust manifold crossover tube, or if injection is both downstream and upstream, then the valve is defective. The relief valve portion of this assembly is defective if air escapes from the silencer at idle. If either of these previous conditions exist, the whole valve must be replaced.


AIR SWITCH/RELIEF VALVE SOLENOID TEST

1. Remove vacuum hoses. With the solenoid wire disconnected air should flow from the vacuum port through the vent port. Energize the solenoid, air should flow through both vacuum ports. If either test fails, the solenoid valve must be replaced.
2. Disconnect electrical connector from solenoid valve.
3. Connect either solenoid terminal to a ground and the other one to the battery positive terminal. The solenoid should make a clicking noise when the connection to the battery is made.
4. If the solenoid does not make a clicking noise, then connect the red lead of a voltmeter to the black wire with an orange tracer, and connect the black lead to ground. Voltmeter should read within 1 volt of battery voltage. If voltage is OK, then replace the solenoid. If voltage is less than battery voltage, then check for power back through the circuit. Trace the power back through the wiring harness to find where power is being lost.

CHECK VALVES

Remove air hose from check valve inlet tube. If exhaust gas comes out of the inlet tube, the valve has failed and must be replaced. If excessive noise is coming from the check valves or tube assembly, then the check valves and/or tube assembly need to be replaced.


DIVERTER VALVE (SOME MODELS)

If air escapes from the silencer at idle and makes excessive noise, then the diverter valve or the relief valve is defective.