Exhaust Gas Recirculation: Testing and Inspection

1. While the engine is cold verify that the system vacuum hoses are properly routed according to the underhood label and that there are no leaks or deterioration.
2. Remove the green striped hose at the EGR valve that comes from the carburetor.

Fig. 57 Testing the EGR valve:

3. Attach a hand vacuum pump to the EGR valve, Fig. 57 and verify that vacuum leaks indicating that the thermo valve is working properly. If vacuum does not leak check the vacuum hose leading from the EGR valve to the thermo valve for restrictions.
4. Start the engine and allow it to reach operating temperature with the transmission in neutral and brakes set. Using the vacuum pump attached in step 3 verify that it is possible to create a 20 in. Hg vacuum in the EGR valve diaphragm chamber indicating that both the EGR valve and thermo valve are functioning. When vacuum is applied the engine should stall. If the engine does not stall check to be sure that the EGR valve is not stuck closed or that the EGR passage is not blocked.

Fig. 58 Testing the vacuum regulator valve:

5. With the engine running at idle, disconnect the white vacuum hose from the nipple of the VRV on the white arrow side, Fig. 58 and connect it to the vacuum pump.
6. Create a 20 in. Hg vacuum. If vacuum leaks the VRV valve is leaking.
7. If a 20 in. Hg vacuum can be maintained the VRV is normal. Disconnect the vacuum hose from nipple A, remove the vacuum pump and attach the hose to its original position.