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Single Air Pump

Air Pump Diagnosis:





DIAGNOSIS


CHECK VALVE

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 valve or tube assembly, then the check valve and/or tube assembly need to be replaced.


DIVERTER VALVE (EXCEPT FEDERAL)

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

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

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 a voltmeter to the green wire of the solenoid and 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.


POWER HEAT CONTROL VALVE

Remove the vacuum line from the power heat control valve and apply 6 inches Hg vacuum to it. The valve should be completely closed. If not, replace the whole valve.

Coolant Vacuum Switch Cold Closed (CVSCC):





COOLANT VACUUM SWITCH COLD CLOSED (CVSCC) (LIGHT DUTY)

ON VEHICLE TEST

1. Check vacuum hoses for correct routing and valve installation. The bottom port is where the source vacuum connects, and the top port connects to the air switch/relief valve.
2. Check engine coolant level.
3. With the valve installed, disconnect molded connector from valve and connect a 1/8" vacuum hose to bottom port of valve.
4. With the radiator top tank warm, about 75°F, blow through the hose.
5. If it is not possible to blow through the hose, replace the valve.
6. Start engine and allow to warm to normal operating temperature. Connect a hand operated vacuum pump to bottom port of valve and apply 10 inches Hg vacuum to the valve. If vacuum drops more than 1 inch in 15 seconds, replace the valve.

BENCH TEST

1. Remove the valve from the vehicle and place the threads in a bowl of ice water that is less than 40°F.
2. Attach a hand-operated vacuum pump to the bottom nipple of the valve.
3. Apply at least 10 inches Hg of vacuum, and make sure that the signal does not drop more than 1 inch in one minute. If the switch cannot hold this vacuum for one minute, then the valve is defective and needs to be replaced.

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