I must admit other than give it a clean this is a mod that I haven't done on my car. I was hoping to see some dyno evidence that it was worth while first.
What I can say is if you open the egr valve via testbook with the engine running at slow speed it causes very noticeable rough running and does a pretty good impression of a duff maf performance wise, hence why I guess it is only designed to open at high speed where the performance impact is reduced and I believe it is its role to reduce emissions that it is there for rather than any other reason.
One of our members came over a couple of weeks ago and his egr gave all the symptoms of sticking open although testing it via Testbook suggests it was not as it would then close and open on demand without delay
The effect on his car was basically rev it up valve opens let the engine tick over and valve seems to take quite a while to close again so until it did the car ran badly. What was not clear was whether the ECU was keeping it open or if it was faulty, even weirder repeating the exercise on my car once fully warmed up showed my valve was not even being opened in the same way I semi wondered at the time if my ECU does actually open it at all and if so the bypass mod would be pointless!
I assume the vacuum pump opens it and some from of internal spring closes it, I wonder if the spring failed could the exhaust gas pressure force and keep it open for a while?
Certainly in his case blanking it off or fitting a bypass may be worthwhile
Anyone cut one up to see how the valve operates and check what sort of gas seal they have when closed?
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