Air Diverter Valve: Testing and Inspection
Air By-Pass Valves:
NORMALLY CLOSED BYPASS VALVES
Function Check
1. At the valve outlet, disconnect the air supply hose.
2. To check to see that a vacuum signal is present at the vacuum nipple, by removing vacuum line. Remove or bypass any restrictors or delay valves in the vacuum line. There must be a vacuum present at the nipple before proceeding.
3. With the engine at 1500 rpm and the vacuum line connected to the vacuum nipple, air pump supply should be felt and heard at the air bypass valve outlet.
4. Disconnect the vacuum line, with the engine at 1500 rpm. Air at the outlet should be shut off, or significantly decreased. Air pump supply air should be felt or heard at the dump port or silencer ports.
5. If the above tests are not successfully completed by the normally closed air bypass valve, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.
Vacuum Reservoirs:
NORMALLY OPEN AIR BYPASS VALVES WITHOUT VACUUM VENT
Function Check
1. At the valve outlet, disconnect the air supply line.
2. Disconnect the vacuum line at the vacuum nipple.
3. Air should be heard and felt at the valve outlet, with the engine at 1500 rpm.
4. Connect a direct vacuum line that is free from restriction from any manifold vacuum source to the vacuum nipple on the air bypass valve. Air at the outlet should be shut off or decreased momentarily.
5. Air pump supply air should be felt or heard at the silencer ports during the momentary dump. Restore all original connections. If the tests above are not completed satisfactorily, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.
Managed Thermactor Air System:
NORMALLY OPEN WITHOUT VACUUM VENT
Function Check
1. At the valve outlet, disconnect the air supply line.
2. Disconnect the vacuum line at the vacuum nipple.
3. Air should be heard and felt at the valve outlet, with the engine at 1500 rpm.
4. Connect a direct vacuum line that is free from restriction from any manifold vacuum source to the vacuum nipple on the air bypass valve. Air at the outlet should be shut off or decreased momentarily.
5. Air pump supply air should be felt or heard at the silencer ports during the momentary dump. Restore all original connections. If the tests above are not completed satisfactorily, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.
EFI Thermactor System:
NORMALLY OPEN AIR BYPASS VALVES HEAVY DUTY
Function Check
1. Disconnect the air supply line at the valve outlet and relief port if applicable.
2. At the vacuum nipple, disconnect the vacuum line.
3. Air should be heard and felt at the valve outlet, with engine at 1500 rpm.
4. Connect a direct vacuum line that if free from restrictions from any manifold vacuum source to the vacuum nipple on the air bypass valve. Air at the outlet should be shut off or decreased momentarily.
5. Air pump supply air should be felt or heard at the silencer ports during the momentary dump. Restore all original connections. If any of the above tests are not satisfactorily completed, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.
Vacuum Check Valve:
NORMALLY OPEN AIR BYPASS VALVES WITH VACUUM VENTS HEAVY DUTY
Function Check
1. Disconnect the air pump supply line at the outlet.
2. At the outlet, disconnect the air pump supply.
3. Air pump supply air should be heard and felt at the outlet, with the engine at 1500 rpm.
4. Using a length of vacuum hose with no devices or restrictors, connect the vacuum nipple to one of the manifold vacuum fittings on the intake manifold. With the engine at 1500 rpm, with the vacuum vent open to atmosphere, virtually no air should be felt at the valve outlet and virtually all air should be bypassed through the silencer ports.
5. Using the same direct vacuum line to an intake manifold vacuum source, cap the vacuum vent. With engine accelerated to 2000 rpm, release throttle suddenly. A momentary interruption of air pump supply air should be felt at the valve outlet.
6. Reconnect all thermactor and vacuum lines. If any of the above tests are not satisfactorily met, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.
Normally Open Without Vaccum Vent:
NORMALLY OPEN WITHOUT VACUUM VENT HEAVY DUTY
Function Check
1. At the valve outlet, disconnect the air supply line.
2. At the vacuum nipple, carefully disconnect the vacuum line.
3. Air should be heard and felt at the valve outlet, with the engine at 1500 rpm.
4. Connect a direct vacuum line that if free from restrictions from any manifold vacuum source to the vacuum nipple on the air bypass valve. Air at the outlet should be shut off or decreased momentarily.
5. During the momentary dump, air pump sully air should be heard or felt at silencer ports. Restore all original connections. If any of the above tests are not satisfactorily completed, check the air pump. If the air pump is operating satisfactorily, replace the air bypass valve.