Hello, I own a 2001 318Ci with 147.000 km (91.000 miles) and recently it threw an check engine light and using INPA I was able to identify it as "Pruefung Kraftstoff-Versorgungssystem" (171), probably indicating an vacuum leak. I cleared it and after a while it came back and I kept doing this to identify the behaviour of the CEL, it seems it always lights up when the engine is warm and when im idling for some time say in front of a traffic light or on my driveway.
I dont really know what it could be but I have been told it could be a bad CCV, I took of the oil cap when idling and it squirted alot of oil droplets and when I put a plastic bag over the cap it sucks it in and back out (and some droplets). anyone knowing what could be going on? the car drives perfectly fine.
Thanks in advance!
The phrase translates into “Testing fuel supply system.” Check the fuel system including the pump and the filter.
Squeeze the rubber intake boot and look for cracks (if the engine is running you'll also notice the engine sounds differently when squeezing). Most likely cause of air intake issues on the M43..
Test fuel pressure at fuel rail,
perform an intake smoke test.
I forgot I asked this question, but I fixed it. The problem was my MAF.
Did not have any errors in the memory as it was not clearly broken. It went out of sync over time. Got the final conclusion by measuring the voltage being output by the MAF at idle and at 2000rpm and compared those with a know working one. The result was about half of the right voltage. Immediately ordered an new MAF sensor, reset CEL and never came back on!
In the meantime fixed all vacuum hoses and such. Now at 200.000km :-) and did alot of part swaps, like oem led taillights and oem xenon to name a few.
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