i think the EGR valve might be causing my erradic idle, so i wanted to either clean it or just replace it...I'm not sure exactly where it is...is there any writup about changing the ERG valve? (i have the edelbrock intake manafold, so maybe there was some issue when it was changed over...any suggestions?)

 

hmm... well im not sure where it would be exactly. but its fairly easy to spot. it should be on the manifold. its a big mushroom shaped part. its probably black.

i know some aftermarket intakes dont have a egr port. so u may not have one.

good luck.

 

well, i have the Edelbrock manafold that is shown in the sticky for TBI, for the common upgrades and info...could this new manafold require a new EGR vlave? or a different one?

 

Shouldn't have a problem with the stock EGR...

... if have you a free flowing exhaust that could be an EGR problem. If your IDLE is irratic, and you suspect the EGR system to be at the root of it, I'd suggest diagnosing the Solenoid first, as the EGR should remain shut at idle without a problem, unless that solenoid to suppling any kind of vac at idle.

Once you look into the solenoid/vac lines, and you still think it is the egr system, and specifically the valve, run a search using my name as the person to search under, and TBI as the forum to search under. A few weeks ago I posted some EGR part numbers that work well in our applications, or at least for me it worked well


However, don't rule out looking into the TPS, IAC, the TBI to manifold gasket itself (known to crack and create a vac leak from hell). All of these things can create odd idling conditions, and the list doesn't stop at just those.

 

wow, thats a lot of potential things to look for, but i did have a diagnostic computer hooked up to my car (from an auto shop) and they could not determine for sure what was causing the problem, but they "think" its the EGR, but they don't know what part of the EGR it is.....any other suggestions?...thanks for the help Nothing else came up on the diagnostic test, so what else should be done?

 

Put a vac guage behind the solenoid - start the car, if you see vac at idle - the solenoid is bad, or the wiring harness has wore insulation and the lead is being grounded someplace.

If you have a Negative backpressure EGR valve, and you don't see vac, and IDLE is ONLY where this problem occurs, take a vac pump and attach it to the egr valve. Give it just enough pressure to move the diaphram up. Too much and the test will be invalid. Have someone else start the vehicle. The EGR *SHOULD* shut. (There were a lot of "And's" in that one ) If the valve does not shut and it is a negative backpressure valve (check beforehand) the spring is weak and the valve needs to be replaced. HOWEVER - if it is NOT a negative backpressure valve, that test will indicate a bad valve that may not be bad at all.



And once again, I urge you to check the for vac leaks, TPS, IAC, Fuel Pressue, etc. before assuming the egr system.