Quote:
Originally Posted by X5Cat
OK, just a little update. Ordered the upstream O2 (air/fuel ratio) sensors and received them earlier this week. Trying to get them in this weekend.
I have a nephew-in-law who works as a tech at a Toyota dealership. Regarding the vacuum leak theory, he is doubting it b/c he thinks if that were the case it would be affecting both banks, not just Bank 2. I see his point, but then I also feel like it would depend on a lot of factors, not the least of which would be the location of the leak -- if there is one.
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Yeah, a good point- although it can depend on location a bit. Can also be a leak combined with old sensor on one bank...
Can you perform a VANOS function test? When vanos soleniods become fouled w old oil, sludge, they can become sluggish and lead to odd performance issues. Not bad enough to throw a code, but they will either fail or show borderline VANOS test results. Should be a program in ISTA or other BMW-specific code reader/computer to do this. A sluggish vanos on one side can mean that side is not seeing the right AFR for part of the RPM range- you get hosed AFRs but it is never so bad, all the time, to trip a full AFR error code
Also, it has been broadly reported that throttle response is poor when the vanos isnt properly adjusting between low and higher RPMs.