Air Flow Meter Diagnosis

[obeidat]

I have '89 320i M20B20
I have lack of power and hesitation problem
I discovered that the AFM cover was opened and maybe adjusted from inside.
Can anybody plz tell me how to Diagnose the AFM and check if it is working properly or not
Thank you in Advance

[Brianmoooore]

You check an AFM by connecting a 6 or 9 volt battery across the ends of the pot. track, and monitoring the voltage on the wiper as you slowly open and close the flap by hand.
Unfortunately, there's no easy way you can check the calibration if you suspect some idiot has changed it.