EGR Valve: Testing and Inspection

Fig. 54 Testing EGR Valve:

1. Start the engine and allow it to idle.
2. Disconnect the vacuum hose from the EGR valve and connect a vacuum pumpto the valve, Fig. 54.
3. Apply 150 mm Hg (6 in. Hg) vacuum to the EGR valve. Vacuum should remain steady and the engine should die.
a. If the vacuum remains steady and the engine dies, the EGR valve is working properly. Remove the vacuum pump and re-connect the vacuum hose; the test is complete.
b. If the valve does not hold vacuum, replace the EGR valve.
c. If vacuum remains steady but the engine does not die; remove the EGR valve and check the valve and the intake manifold for blockages in the EGR passage. Clean or replace as necessary.