Time Delay System Test Timer

1. Stop engine and then restart. Immediately open throttle to about 1000 RPM and observe EGR valve stem for movement.
2. If EGR valve moves within the first 30 seconds after starting, the EGR time delay system is defective.
3. Check hose connections to the time delay solenoid valve. Disconnect electrical plug from solenoid valve and energize valve by grounding either terminal and connecting other terminal to battery positive. If EGR valve stem now moves, the solenoid is defective and should be replaced. If EGR valve does not move, EGR valve timer may be defective, or there may be a problem in the wiring harness.
4. If control system is functioning properly, the valve and passages may be checked for exhaust gas flow. With engine at operating temperature and idling and with transmission in Neutral, apply 10 inches Hg vacuum directly to the EGR control valve. Idle speed should drop 150 RPM or more. This speed change confirms that exhaust gas is recirculating. If not, exhaust deposits in the EGR valve or intake manifold EGR passages are indicated.