M42 AFM Swap

[AmericanIcon]

So I own an M42 swapped 2002 (which is a blast), however there's a few things that need work. One of them is the AFM. Ive taken the old one apart and fixed it, but it's still a bit wonky sometimes. The motor is from a 1990 e30 318is

I bought a 1995 BMW 318ti with an M42. I took the AFM off the e36 and put it on the e30 motor. And then the car would barely start. It was a very lumpy idle and would cut out after about 15 seconds.

Does anyone know why? I've accepted that they are probably different underneath but does anyone have any links/data/experience for this? I've not been able to find anything about the AFM on either motor as to the differences between them. Not really worried if it doesn't work, just curious why.

[roguetoaster]

There does seem to be some difference between some E36 M42 AFMs (two different part #s) and E30s (one part #). I have experienced this myself when swapping an E30 AFM on to a '95 318ti, which caused the car to run even worse despite working fine on the E30.

There is reference to a CO potentiometer in one of the E36 part numbers, but I can't verify the difference.

Also, what do you mean you fixed your old AFM?

[AmericanIcon]

There does seem to be some difference between some E36 M42 AFMs (two different part #s) and E30s (one part #). I have experienced this myself when swapping an E30 AFM on to a '95 318ti, which caused the car to run even worse despite working fine on the E30.

There is reference to a CO potentiometer in one of the E36 part numbers, but I can't verify the difference.

Also, what do you mean you fixed your old AFM?

All I did was reset the arm on the resistor track. But I had to open it up and mess with something I’d rather leave alone. But my broke college student income says otherwise haha.