idiot-stick

If you remove an EGR valve from the car and blow into one of the 2 ports, should you be able to blow through it?

Im trying to diagnose my wife's 97 lude and im able to blow through it, wondering if its a bad EGR valve or not

JDMFantasy2K

that's pretty vague. An EGR valve should work similar to a wastegate, essentially it's bleeding exhaust gas into the intake manifold. Egr's can be of many different designs but basically it should work so that when vacuum is applied the valve opens or closed depending on the design. Try sucking on the port. You may have to push on the piston a little because there would normally be some pressure there from the exhaust gasses. Take a picture of it to. Also why do you think you have an EGR problem?

idiot-stick

Well with this design, it's vacuum operated to OPEN, so if you removed it from the car, it's as closed as it's ever gonna get b/c it remains CLOSED via spring or diaphragm pressure. So you shouldnt be able to blow through it easily with the car off, but that was the case.

I have been working on my wife's prelude SH. It had a nasty rough idle and hard starts when warm. I blocked off the EGR last night and it now runs like a new car. The EGR valve was letting hot exhaust gas get re-combusted during idle.

JDMFantasy2K

yeah, good diagnosis. So is the valve's diagphram shot?

idiot-stick

Yup that sounds like it. Bringing it to a dealership tomorrow and getting it fix via extended warranty. wewt.

For now I fabbed a block off plate for going inbetween the manifold and EGR valve. Engine runs like absolute perfection.