EGR Sytem Failure

[rtexas]

I've been going through this forum and following instuctions in here for weeks on this problem. It started with a check engine light.

To date I have pulled the EGR and BPT valve as well as the tube from the exhaust manifold and cleaned them. Have cleaned the connections at the selenoid as well. The EGR seems to work as it opens when a vacume is placed on it. It stays open as long as vacume is applied and immediately closes when it is released. I have replaced all of the vacume hoses. They were all in pretty rough shape. There seems to be a leak in the brass tube that connects the BPT to the Air Intake so I by-passed that. Now, The check engine light does not come on and stay on anymore. It just comes on when I accelerate and goes back off when I let off of the gas. It doesn't throw the code anymore but I still think this light still has something to do with this system. I'm trying to get it inspection ready and this is the last item on the list.

The vacume going from the air intake to the BPT does not have very much vacume on it so I ran vacume straight from the canister to the BPT valve. The engine started running rough at idle as though I were running it straight to the EGR valve. Is that normal? From what I have read, the BPT valve doesn't send vacume to the EGR until the engine gets to approx 1500- 2000 RPM.

Any ideas where to go from here would be appreciated.

[Magnes]

The BPT doesn't cut the vacuum to the EGR. it just opens it to atmosphere to 'bleed it off'. If the vacuum is strong enough, some of the 'bleed' will come from the EGR itself, meaning it will be partly activated.

As for the CEL coming on only during accel and no codes set, it might be related, I don't know. Plug the original vacuum line back in and let us know if the CEL problem continues.

Modified by Magnes at 10:52 AM 12/14/2005

Modified by Magnes at 10:53 AM 12/14/2005
Modified by Magnes at 10:54 AM 12/14/2005

[rtexas]

Could an exhaust leak cause this by causing the backpressure to fluctuate? I noticed a pretty nasty ding close to the cat.

[Magnes]

Yeah, it's hard to know the effect of changes to the exhaust system, as it concerns backpressure and pulsations, so you might get some negative impact on your EGR due to leaks or restrictions in the pipe.

[Chezedik]

If you want to try it out, I have these parts for sale for [email protected]