Thermal Vacuum Valve: Testing and Inspection

Conditions

^ Disconnect both nipples of the thermactor idle vacuum (TIV) valve.

^ Install a vacuum hose from the manifold vacuum source to the small nipple of the TIV valve.



Checks

TIV valves with code words ASH or RED on decal:

1. With the engine at idle, in Neutral, place fingers over the TIV valve atmospheric vent holes. If no vacuum is sensed, the TIV is defective and must be replaced.

2. While the engine is still idling in neutral, apply vacuum, shown below, to the TIV valve large nipple from a test source. If vacuum is still sensed when placing fingers over vent holes, The TIV is defective and must be replaced.

3. Disconnect the TIV large nipple from manifold vacuum and the TIV small nipple from the test vacuum. Reconnect the TIV valve to original hoses or connectors.


TIV valves with code mode TUR on decal:


1. With the engine at idle, transmission in Neutral, place fingers over TIV valve atmospheric vent holes. If vacuum is sensed, the TIV is defective and must be replaced.

2. While the engine is still idling in Neutral, apply pressure, shown below, to the TIV valve's large nipple from a test source If vacuum is not sensed when placing a finger over the vent holes, the TIV is defective and must be replaced.

3. Disconnect the TIV valve's large nipple from manifold vacuum and the small nipple from the test pressure. Reconnect the TIV to its original hoses or connectors.