AFM help e21

[Gruppe5]

ok guys I have an 82 320i

I swapped on the 2.0 afm which is much larger and after the pain that was I had a bunch of problems getting it going.

To start the car wouldn't even run and took full throttle just to get it started at which point it would take over 50% throttle to keep alive. I reconnected all of the vacuum hoses and that helped to solve the problem. The car would turn on and stay on with much less effort, but still required at least 10-15% throttle to stay alive. I would give it enough gas to hold at 3k then it would slowly drop off until it dropped to nearly dying and would bump back up to 2800. Then after a while tinkering with the hoses and making sure everything was connected I noticed that the afm didn't seem to move freely and had a bit of resistance. I think this resistance is what is causing it to not hold idle and to need as much throttle as it needs to start. What do you guys think.

Sorry for my first post to be a problem.

[PatAllen]

ok guys I have an 82 320i

I swapped on the 2.0 afm which is much larger and after the pain that was I had a bunch of problems getting it going.

To start the car wouldn't even run and took full throttle just to get it started at which point it would take over 50% throttle to keep alive. I reconnected all of the vacuum hoses and that helped to solve the problem. The car would turn on and stay on with much less effort, but still required at least 10-15% throttle to stay alive. I would give it enough gas to hold at 3k then it would slowly drop off until it dropped to nearly dying and would bump back up to 2800. Then after a while tinkering with the hoses and making sure everything was connected I noticed that the afm didn't seem to move freely and had a bit of resistance. I think this resistance is what is causing it to not hold idle and to need as much throttle as it needs to start. What do you guys think.

Sorry for my first post to be a problem.

I once had a 320i too, and made the exact same swap, from a VW GTI. No difference at all, the throtle body on a stock 80-83 320i is soo small.

Yes the plate needs to move totaly freely, the center nut (10mm) can be loosened to center the plate, but you have to be very precautious when playing with that. Make sure there is no leak at all from the throtle to the metering device. Any small leak will cause problems there.

you MUST find a way to change the throtle to benefit of the gain of the bigger mettering device.

[Gruppe5]

Thanks Pat, did you have the same troubles getting yours to start and run? mine has just been a pain and I'm about to swap the 1.8 afm back it. the 11.8 tiny though and another e21er said he got massive gains from his. Do you think it's possible that I just need to readjust the a/f?

[PatAllen]

Thanks Pat, did you have the same troubles getting yours to start and run? mine has just been a pain and I'm about to swap the 1.8 afm back it. the 11.8 tiny though and another e21er said he got massive gains from his. Do you think it's possible that I just need to readjust the a/f?

I didnt had any issues so far, its been a while...

yes you alway need to readjust the a/f, but that shouldnt make it act liek you describe, probably just idle that can be wrong. With everything adjusted as before except the afm, just adjust the allen key into the afm so you get a decent idle, then test it on the road.

at idle, once it is adjuted, flip the wot micro switch, the idle must go a bit down as the system is enriching a lot. If the rpm rises then the idle mixture is on the lean side.

hth