Air Vent Cut-Off Diaphragm

Air Vent Cut-Off Diaphragm





1. Disconnect the hose at the air vent cut-off diaphragm and install a vacuum pump to the hose.
2. Apply vacuum.

Vacuum should not hold.

3. Turn ignition switch on.

4. Apply vacuum.

Vacuum should remain steady.

- If vacuum holds go on to step 5.





- If vacuum does not hold, check for leaks in hose connections. If vacuum is still does not hold, check for voltage at vacuum holding solenoid valve.
- If there is voltage, replace vacuum holding solenoid valve and retest.
- If no voltage, check the wiring (Black/Yellow).

5. Start engine allow to idle and check for vacuum.

Vacuum should be available.

- If vacuum is available, go to step 6.
- If vacuum is not available, check for blockage in hose. If vacuum is still not available, replace vacuum holding solenoid valve and retest.

6. Turn ignition off.

Vacuum should drop to zero.

7. Disconnect the vacuum pump from vacuum holding solenoid valve hose and connect to air vent cut-off diaphragm. Apply a vacuum.

Vacuum should remain steady.

- If vacuum remains stable, diaphragm is OK.
- If vacuum decreases, replace diaphragm and retest.

8. Remove the vacuum pump and reconnect hose between the air vent cut-off diaphragm and the vacuum holding solenoid valve.