pipe coming off fuel regulator on m20

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bmw9818
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Post Fri Sep 13, 2013 7:22 pm

quick q, the pipe coming off the fpr going to the intake is badly perished, does it deal with a large amount of fuel? or can it last a few days its got deep cracking at the ends,

and ive recently begun noticing a slight smell of petrol,

which is where i noticed it...
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Brianmoooore
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Post Fri Sep 13, 2013 7:37 pm

No fuel in it at all (or there shouldn't be).
It's a vacuum pipe that adjusts the fuel pressure with changes in plenum pressure. With it disconnected, your fuel pressure will be too high at part throttle, resulting in too much fuel being injected, but you will also have a small air leak into the inlet manifold, bypassing the AFM, which will weaken the mixture.
Whether these two opposing each other results in a weak mixture, a rich mixture, or one that is almost correct, I have no idea, but it isn't going to hurt for a few days.
You've reminded me that the equivalent pipe fell off of my E39 while I was on holiday in Germany a couple of weeks ago, and I still haven't done anything about it!
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Post Fri Sep 13, 2013 9:42 pm

If that is in a bad state I would be looking at all the pipes and replacing as needed just in case.
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