I've been chasing a 2B64 code (unmetered air) for a few weeks now. Symptoms are fluctuating idle bouncing between ~700-1200 rpm with the occasional burp and gurgle it's particularly bad with cold starts. Other that that runs fine across all rpm and throttle input and pulls well, boost is ok. Have checked: all air intake piping and vac lines with the brake clean and/or spray-9 technique as well as smoke test. Pulled vanos solenoid cleaned and tested function (it was immaculate). Cleaned MAF (twice).

I was reading another thread about 2b64 and someone suggested to that OP to unplug the MAF and see how it runs. I tried that on the weekend and too my initial joy, the idle was a stead 750 rpm and after a few short drives the 2b64 code did not return. So my conclusion is bad MAF. Obviously can't drive with the MAF unplugged for long term because it's running super rich due to the ecu table values putting the afr into a safe range. Also noticeably down on power with MAF unplugged.

BUT, now I'm about to purchase a MAF....and second guessing my diagnosis. Is it possible that the unplugged MAF is hiding the real problem? In other words, if the real issue is, for example, a leaky vac line would the 2b64 code still appear with the MAF unplugged?

tia,

sani

 

Curious if you ever found out the problem?

just bought a 2007 S and after three days of owning it getting this code. Husband has very little mini/bwm experience but was a mechanic in the army for 20 years.

replaced Vanos yesterday as we saw on another post that might be a solution.

any info on what fixed yours is appreciated!