EGR Valve: Testing and Inspection

Fig. 26 Testing EGR Valve (California):

1. Start the engine and let it reach normal operating temperature (coolant fan should cycle on and off at least once).
2. Disconnect and plug the vacuum line to the EGR valve.
3. Connect a hand operated vacuum pump to the EGR valve, Fig. 26.
4. With the engine running, apply 400 mm (16 in.) Hg of vacuum to the valve.
The engine speed must gradually drop while applying vacuum.
The engine speed should return to normal after releasing vacuum from the valve.
5. If the engine speed does not change, remove the EGR valve return line and repeat the test.
6. If the speed changes with the return line disconnected, replace the return line.
7. If the speed still does not change, or if the idle speed does not return to normal after the test, replace the EGR valve.