EGR Valve: Testing and Inspection

NOTE: This is not to be used as a complete test of the EGR system.

EGR Value and EGR Value-Typical:

If the engine will not idle, dies out on idle, or idle is rough or slow, the poppet valve at the base of the EGR valve may be leaking in the closed position.

1. The engine should be off for the following test.
2. Disconnect the rubber hose from the fitting at the top (vacuum motor) side of the EGR valve.
a Connect a hand-held vacuum pump to this fitting.
b. Apply 15 inches of vacuum to the pump.
c. Observe the gauge reading on the pump.
d. If vacuum falls off, the diaphragm in the EGR valve has ruptured.
e. Replace the EGR valve.

NOTE : The EGR valve, valve control and attaching hoses are serviced as one assembly. Refer to EGR Valve Removal/Installation.

f. Proceed to the next step.
3. A small metal fitting (back-pressure fitting) is located at the base of the EGR valve. A rubber back-pressure hose connects it to the back-pressure fitting on the EGR valve control. Disconnect this rubber hose at the EGR valve fitting.
4. Remove the air cleaner housing from the throttle body.
5. Using compressed air, and using an air nozzle with a rubber tip, apply approximately 50 psi of regulated shop air to the metal back- pressure fitting on the EGR valve.
6. By hand, open the throttle to the wide open position. Air SHOULD NOT BE HEARD emitting from the intake manifold while applying air pressure at the back-pressure fitting.
7. If air CAN BE HEARD emitting from the intake manifold, the poppet valve is leaking at the bottom of the EGR valve. Replace the EGR valve. Note: The EGR valve, valve control and attaching hoses are serviced as one assembly. Refer to EGR Valve Removal/Installation. Do not attempt clean the old EGR valve.