How do I replace The Egr valve on my 90 accord? I'm almost certain it is bad. When I disconnect the vaccum the car runs fine, when it is connected it runs rough.

Most EGRs have two bolts holding them on...pretty straightforward. Is there something odd looking about yours? (I can't remember what a 1990's looks like)

Nothing odd, didn't know if I could just replace the valve without making any other adjustments.

Nothing odd, didn't know if I could just replace the valve without making any other adjustments.

No, nothing weird. Looks like there is a crossover pipe from the exhaust you have to take off, I think...and if the passages look hogged up, try to clean them out...I keep a shopvac right there while I do it, so it sucks the crud up rather than letting it fall into the passages...

http://img202.exs.cx/img202/6951/intakemanisale8kc.jpg

THX Jeff for your help I'll give it a try.

I wouldn't buy an EGR valve just yet. You need to do some testing. And we need more information. Is this rough idling at idle or between 1500-2500RPM?
Connect a vacuum guage to the hose going to the EGR. Do you have vacuum at idle? Get back to us with this information.

I wouldn't buy an EGR valve just yet. You need to do some testing. And we need more information. Is this rough idling at idle or between 1500-2500RPM?
Connect a vacuum guage to the hose going to the EGR. Do you have vacuum at idle? Get back to us with this information.

Uh-oh, what do they have a vac delay or modulator on the EGR line or something? I didn't think about that...

Vacuum to the EGR is controlled by a EGR solenoid powered by the ECU. Based on engine temp and RPM and a signal from the MAP, the ECU grounds one side of the solenoid which activates it and sends vacuum to the EGR. Engine RPM needs to be 1500-2500 and the engine hot. Usually when the EGR fails, everything works great but won't pass smog. (High NOX).