EGR System
- Connect a tachometer to engine. Connect vacuum gauge between EGR valve and EGR vacuum port. With engine cold, start engine and check that vacuum gauge indicates no vacuum at idle.
- Warm engine to operating temperature. Check that vacuum gauge indicates no vacuum at idle. Increase engine speed to 2000 RPM. Vacuum gauge should indicate over 6 in. Hg. Disconnect and plug vacuum hose to EGR valve.
- Engine speed should increase. Stop engine, push diaphragm plate by hand and release it. Check that diaphragm plate returns smoothly to original position.
- If 6 in. Hg was not obtained in step 2), check vacuum hoses and ports for restrictions or leaks. If EGR valve did not perform as stated in step 3), replace EGR valve.