Can an AFM be tested.

[ah]

I think my AFM may on its way out,is there anyway of testing it.

[buster]

Put car on a co meter, twidle the adjuster see if it makes a differance to the co readings. Or borrow another known working one to see if it drives any better.
Thats all i can think of

[Brianmoooore]

An E30 AFM assembly consists of three items. It contains the CO adjustment pot or bypass, which frankly there isn't a lot likely to go wrong with (other than it being moved by bodgers), the inlet air temp. sensor, which again is reliable, but can be checked by a simple resistance measurement at a few different temperatures, and the AFM itself, which I assume is the part you actually want to check.
You will find articles, (hopefully NOT in the wiki) showing you how it can be tested with a resistance meter. These do not work!
To test the AFM, you need to connect a six or nine volt small battery across the outer terminals of the pot. track, then connect a voltmeter, preferably analogue, or even better, an oscilloscope, between one of the battery terminals and the rotor of the pot. You then slowly open the flap of the AFM, watching the voltage as you do. You are looking for a voltage that increases slowly as you do, or more accurately, one that NEVER drops back, even slightly, or for the briefest instant.

[ah]

Thanks another perfect answer from Mr brianmooore thanks I'll try your advice.

[DanThe]

I can get these reconditioned to as new condition if needed