Seeking knowledge from our oracle, Bill R

[rob101]

Bill, What are the most common symptoms associated with a faulty Air Flow meter. I get roughness at idle and on low throttle, I suspect a couple of things but AFM is starting to become a prime suspect.

[Bill R.]

airflow meter, it has a maf. A mass air flow sensor. I wouldn't think that it would be the maf from what your desribing.. I'd check carefully for intake leaks between the maf and the engine such as cracked hoses poor connections, Look for vacum leaks at the icv. I haven't replaced any mafs on bmw's yet. But i really don't work on that many bmw's either. On other cars such as gm products there are numerous indicators of a bad maf such as hard starting, random stalling and not restarting until the car cools down etc.. On most of the mafs on american cars that i've changed you can tap on it with a screwdriver with the engine idling and it will start to stall.
But now that i've written this i see that your referring to your 528. It sounds like the idle airfuel ratio may be a little off causing idle roughness and a flatspot on initial acceleration.. You have an adjusting screw on your afm to richen the mix up slightly at idle and off throttle. I'd check that setting first and check the throttle position switch to make sure that its working correctly too. As usual air leaks will play a big part in idle roughness and off idle. Check all hoses from the afm to the engine, even the slightest leak will have an effect. I don't really see many bad afm's and feel that its probably blamed alot and replaced needlessly



Bill, What are the most common symptoms associated with a faulty Air Flow meter. I get roughness at idle and on low throttle, I suspect a couple of things but AFM is starting to become a prime suspect.

[rob101]

airflow meter, it has a maf. A mass air flow sensor
actually i was kind of asking about my m30 528i, but thanks for the heads up, I haven't really pulled much of my intake apart in my m50 anyway. Sorry for the confusion

[winfred]

those are easy to clean just pry the top off of it and clean the trace with a lint free rag and non residual solvent, i use electrical contact cleaner sprayed on the rag to wipe the surface and then gently lift up the wiper and slide a thin wet part of the rag under it to clean those contacts


actually i was kind of asking about my m30 528i, but thanks for the heads up, I haven't really pulled much of my intake apart in my m50 anyway. Sorry for the confusion