Exhaust Gas Recirculation: Testing and Inspection

EGR Valve And Sensor Assembly:

ELECTRONIC EGR (EEGR) VALVE
1. Verify that all vacuum hoses are routed correctly and securely attached. Replace crimped, cracked, or broken hoses.
2. With the engine at normal operating temperature, make certain there is less than 2.5 in-Hg vacuum to the EGR valve.
NOTE: The EVR solenoid has a constant internal leak. A small vacuum signal will be noticed. This signal should be less than 1.0 in-Hg at idle.
3. Install a tachometer.
4. Disconnect the Idle Air Bypass Valve electrical connector (EFI engines only).
5. From the EGR valve nipple remove the vacuum supply hose, then plug those.
6. Start engine, while at idle in neutral, observe engine idle speed. If necessary, adjust idle speed.
7. Using a hand vacuum pump, slowly apply 5-10 inches of mercury vacuum to the EGR valve vacuum nipple.
8. When vacuum is applied to the EGR valve and any of the following occur:
Engine does not stall
Idle speed does not drop more than 100 rpm
After the vacuum is removed, the idle speed does not return to normal (+/- 25 rpm)
For vacuum leak at EGR valve, replace the valve.
Check for contamination and clean the EGR valve, using EGR valve cleaner or equivalent.
Make sure there is no sand left in the valve.
Replace the EGR valve is necessary.
9. Reconnect the idle air bypass valve electrical connector. Unplug and reconnect the EGR vacuum supply hose.
10. If EGR system is ok, replace EGR sensor if Continuous Code 32 is present. If Continuous Code 32 is not present, refer to COMPUTERIZED ENGINE CONTROLS.