Exhaust Gas Recirculation: Testing and Inspection

Typical EGR Valve And System Check:

1. Verify vacuum hoses are properly routed and securely attached. Replace crimped, cracked, or broken hoses.
2. Check the EGR Valve for loose attaching bolts or damaged flange gasket.
3. Make any needed repairs and verify symptom still exists.
4. Start engine and run until normal operating temperature is reached.
5. Disconnect the vacuum supply hose at the EGR Valve and check for a vacuum signal.
NOTE: The EVR solenoid has a constant internal leak, causing a small vacuum signal (less than 1") to be noticed at idle.
6. Connect a tachometer.
7. Verify Idle speed is set to specifications with the transmission in NEUTRAL.
8. Disconnect the idle air bypass valve electrical connector.
9. Remove and plug the EGR Valve vacuum supply hose at the EGR Valve.
10. Using a hand vacuum pump, slowly apply 5-10 inches of vacuum to the EGR valve vacuum nipple.
11. When vacuum is applied to the EGR valve, the idle speed should drop more than 100 rpm or the engine should stall.
If not, check the EGR Valve for contamination and/or sticking. Check exhaust passages for blockage.
Clean valve and/or passages. Replace valve if necessary.
12. Reconnect the idle air bypass valve electrical connector. Reconnect the EGR vacuum supply hose.