Exhaust Gas Recirculation: Testing and Inspection

Troubles in the EGR system can cause:
Poor starting
Poor idling
Stalling
Cold engine hesitation
Poor overall performance
Check the EGR system if any of these problems are observed.




1. Make sure that all vacuum hoses and vacuum hose connections are in good condition and not leaking.
2. Start the engine and warm it up to at least 60°C (140°F).
3. With the engine idling, check that there are no leaks in the exhaust line that connects the EGR valve with the exhaust manifold. Replace any line that leaks.
4. Disconnect the vacuum hose from the EGR valve and connect a vacuum source to the valve.
NOTE: For a vacuum source either a hand operated pump, or the retard line to the distributor will work.
5. With vacuum applied to the EGR valve, the idle speed should drop or the engine should stall. If the engine speed does not change, check for a clogged EGR line or a blocked or faulty EGR valve.
6. If the idle speed drops with vacuum applied to the EGR valve but the engine still has trouble with cold starts and cold running, check the thermo-vacuum valve.