Vacuum Solenoid Valve Test
- With engine at normal operating temperature, engine idling and transmission in neutral, make sure choke plate is fully open.
- Turn off air conditioner, power take-off (if equipped), and all accessories. Disconnect vacuum supply hose at solenoid valve and check for vacuum. If no vacuum is present, clean or replace hose as required.
- If a vacuum delay valve is used, remove valve and install a straight connector. Disconnect wires to solenoid valve. With a jumper wire, apply battery voltage to one of the solenoid terminals. The engine speed should not increase. If it does, replace the solenoid valve.
- With battery voltage on one terminal, use a second jumper wire to ground the other terminal of the valve. The engine speed should increase, if not, replace the valve.
- Remove the ground jumper wire. The engine should return to idle within 15 seconds. If not, replace the solenoid valve.