Hello all,
I recently had a P0171 code (too lean bank 1) come up after I noticed a check engine light on my 66-plate 218i (42k miles), as well as high idle speeds. When the engine is hot and I'm at idle (usually at traffic lights or junctions), the revs slowly creep up to 1800 without me pressing on the accelerator.
I went to an independent bimmer specialist who ran through their diagnostics saying it was likely a vacuum leak so they did a smoke test and found nothing. They said the next stage on their list was to check for "engine updates" (presumably ECU updates) which there were, so I got the update and was told it shouldn't come back. They deleted the codes but the day after I was getting the same high idling, so I took it back there and they ran it through the machine again but no codes appeared.
The guy then told me he vaguely remembers another customer with a similar issue and it turned out to be a "fuel tank breather valve" although that customer had the code for it whereas I don't. So before I go and throw money at the problem based on what the mechanics "think" it is, I was wondering if anyone else has had this issue or has any suggestions? I was thinking maybe a MAF sensor or lambda sensor? So far diagnostics + smoke test + engine update have cost me upwards of ÂŁ180 and since I'm a uni student I'd rather not keep feeding the money pit to make unnecessary repairs and I feel I may be taken advantage of due to being young...if it has to be done it has to be done though. I can do the MAF myself anyway.
Would really appreciate it if anyone has any idea, even if you're not too sure. Many thanks.
I recently had a P0171 code (too lean bank 1) come up after I noticed a check engine light on my 66-plate 218i (42k miles), as well as high idle speeds. When the engine is hot and I'm at idle (usually at traffic lights or junctions), the revs slowly creep up to 1800 without me pressing on the accelerator.
I went to an independent bimmer specialist who ran through their diagnostics saying it was likely a vacuum leak so they did a smoke test and found nothing. They said the next stage on their list was to check for "engine updates" (presumably ECU updates) which there were, so I got the update and was told it shouldn't come back. They deleted the codes but the day after I was getting the same high idling, so I took it back there and they ran it through the machine again but no codes appeared.
The guy then told me he vaguely remembers another customer with a similar issue and it turned out to be a "fuel tank breather valve" although that customer had the code for it whereas I don't. So before I go and throw money at the problem based on what the mechanics "think" it is, I was wondering if anyone else has had this issue or has any suggestions? I was thinking maybe a MAF sensor or lambda sensor? So far diagnostics + smoke test + engine update have cost me upwards of ÂŁ180 and since I'm a uni student I'd rather not keep feeding the money pit to make unnecessary repairs and I feel I may be taken advantage of due to being young...if it has to be done it has to be done though. I can do the MAF myself anyway.
Would really appreciate it if anyone has any idea, even if you're not too sure. Many thanks.