EGR Valve Leak Test

NOTE: If the engine will not idle, dies out at idle, or idle is rough or slow. the poppet valve at the base of this EGR valve may he leaking in the closed position. The diaphragm within the EGR valve may also be ruptured.

1. The engine should be off for the driving test
2. Disconnect the rubber hose from the fitting at the top, vacuum motor, of the EGR valve
a. Connect a hand-held vacuum pump 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 is ruptured.
e. Replace the EGR valve.
f. Proceed to next step.
3. A small fitting (back pressure fitting is located at the base of the EGR valve).
- A rubber hose connects it to the back-pressure fitting on the EGR valve control.
- Disconnect this rubber hose at the EGR valve.
4. Remove air inlet tube from throttle body.
5. Using compressed air and 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 coming from the intake manifold.
7. If air can be heard coming from inside the intake manifold, the poppet valve is leaking at the bottom of the EGR valve.
- Replace the EGR valve. Do not attempt to clean the old EGR valve.