EGR valve question.

I'm a real dummy when it comes to egr valves and stuff. But when you unplug the egr valve while the car is idling, is there supposed to be a change in the idle? Like in RPM's or sputtering or anything.

No. The EGR is simply a metered path from exhaust to intake. At idle if the EGR were OPENED, it would cause the motor to die, just like a massive vacuum leak would.

Disabling it would have no effect at idle. The EGR only opens during periods of high load (low vacuum) like heavy acceleration or hill climbing. By contaminating the intake charge with exhaust, the combustion temp drops, inhibiting the production of N0x emissions. It has a small effect on reducing pinging as well.

Just to clarify...if you are dealing with an older style EGR that is vacuum operated, and which uses manifold vacuum rather than ported vacuum (below the throttle plate, rather than above), like some older Fords, you will of course get some reaction just from the vacuum leak of the line you unplugged, if you don't cap it.


I assume you are talking about a newer one. Most now are ECM controlled and operated by an electric stepper motor rather than a vacuum diaphragm, but some of the older Lumina's still used a vacuum EGR.

It's on a '92 Lumina Euro w/ 3.1L eng.