Curious CEL Issue

I have a 2000 M Roadster with low miles and no engine mods. About 6 mos ago, the check engine light began appearing -- registered "EVAP system, Incorrect purge flow" and/or "EVAP system, Leak detected (large leak)".

The common circumstance for the light appearing seems to be driving at freeway speeds (55-65mph) for a reasonable period (more than 15 mins, let's say) then sitting at idle for a few seconds (like exiting the freeway and stopping for a red light). Doesn't happen EVERY time under those circumstances, but probably 80% of the time.

Have searched the board and as a result I've had the gas cap pressure tested (during VA state inspection -- it passed) and I don't overfill the gas tank.

I've been resetting the CEL light with a Peake tool and the car drives fine, but would like to fix the problem if possible. Any other ideas?

Thanks.

Reply » Curious CEL Issue

Try getting a new gascap... 90% of the time the fault occurs when the gas cap is left off, but I doubt you're doing that repeatedly. I know that there are updated gas caps available from BMW, if yours is shot and not sealing, it could do that...

otherwise the incorrect purge flow... hmm. I know there is an evap purge valve, if its not working properly??

Reply » Curious CEL Issue

There was some type of vacuum pump in the gas tank that needed to be replaced.

Ken

Reply » Curious CEL Issue

Will look into a new gas cap -- I think the original one is fine, but could be an inexpensive fix.

Ken, was your pump replaced under warranty? If not, what kind of costs am I likely to face?

Thanks again,
Matt

Reply » Curious CEL Issue

It was replaced under warranty so I don't know the cost. I think they were able to determine the problem from the code, so pulling the code may identify your problem.

Ken

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