AFM wiper position

[JTDay]

Trying to diagnose years of poor running issues, taking it step by step. I can't find a definitive answer for this as I'm sure it hasn't been addressed very often, but onto the issue:

From the few photos I could find, it seems that with the car off, the position of the contacts on the wiper arm should be at the first contact strip like in the photo below (I think this might be an m30 AFM, but you get the idea):




Mine, however, rests at the second contact position when the car is off, as illustrated in the photo below:

Idk much about how this system works but I assume that it SHOULD NOT be like this. How do I adjust it so that it can be like factory?




Thanks,

Josh

[Gregs///M]

Yours is in the correct position. Position 1 is for full throttle or "high air intake."

Your AFM resistor strip is severely worn and Im sure you need to adjust it. See my signature for AFM info under "services"

[paperplane94]

I think the OP is right, it does look to be on the second notch.

You can adjust it by loosening the phillips head screw on the arm. There should be a bit of glue on it.
BUT FIRST find a way of marking the original wiper position before changing anything in case things take a bad turn.

Also as mentioned, the tracks are very worn. REad this for a possible remedy:
http://www.iprimus.ca/~trauttf/temp/AFM/

[jlevie]

Have you checked to see if the vane is closing all the way?

[JTDay]

Yours is in the correct position. Position 1 is for full throttle or "high air intake."

Your AFM resistor strip is severely worn and Im sure you need to adjust it. See my signature for AFM info under "services"

Nice write up. When I say "1", I'm talking about the first contact strip when the AFM is at rest. Are you thinking that I meant position 1 to be the labeled "1" in the first photo I posted?

I think the OP is right, it does look to be on the second notch.

You can adjust it by loosening the phillips head screw on the arm. There should be a bit of glue on it.
BUT FIRST find a way of marking the original wiper position before changing anything in case things take a bad turn.

Also as mentioned, the tracks are very worn. REad this for a possible remedy:
http://www.iprimus.ca/~trauttf/temp/AFM/

Great information sources here. All the photos I've seen suggest that it should be at the first contact strip.

Have you checked to see if the vane is closing all the way?

I assume by your reference to "vein", you're talking about the barn door thing inside the AFM housing? At rest, it does not close all the way. I can turn the wiper arm assembly clockwise and it becomes fully closed when the arm is pointing at the first contact strip. It's like there's too much tension or something on the big spring in there to allow it to fully close. Can I adjust it so it's how it's supposed to be or do I just need to get a new/refurb AFM?


Thanks for the replies fellas,
Josh

[Gregs///M]

Nice write up. When I say "1", I'm talking about the first contact strip when the AFM is at rest. Are you thinking that I meant position 1 to be the labeled "1" in the first photo I posted?




Great information sources here. All the photos I've seen suggest that it should be at the first contact strip.





I assume by your reference to "vein", you're talking about the barn door thing inside the AFM housing? At rest, it does not close all the way. I can turn the wiper arm assembly clockwise and it becomes fully closed when the arm is pointing at the first contact strip. It's like there's too much tension or something on the big spring in there to allow it to fully close. Can I adjust it so it's how it's supposed to be or do I just need to get a new/refurb AFM?


Thanks for the replies fellas,
Josh

Yes, I did assume the position of #1. Showing the picture was confusing. Your AFM internal flap should open all the way and close all the way. You obviously have an obstruction and your AFM flap is failing to close.

Do not adjust the spring to try to fix this. Do not loosen the screw on top of the wiper arm. Bosch very closely laser calibrates each AFM at the factory and adjusting the spring of screw would throw off calibration big time.

If the AFM cannot close, try cleaning the inside more. If you continue to have issues with it closing, I recommend you replace the AFM. Taking apart the AFM and cleaning it and reassembling it would only leave you with an AFM that opens and closes but calibration factory would be drastically off from factory spec.

With the AFM not closing, it would be sending your ECM an approx value of 1 volts when it would be expecting 0.5 volts. Max output is 4.8-5 volts (at fully open) This would throw off driveability and fuel/air mixture.

[JTDay]

Yes, I did assume the position of #1. Showing the picture was confusing. Your AFM internal flap should open all the way and close all the way. You obviously have an obstruction and your AFM flap is failing to close.

Do not adjust the spring to try to fix this. Do not loosen the screw on top of the wiper arm. Bosch very closely laser calibrates each AFM at the factory and adjusting the spring of screw would throw off calibration big time.

If the AFM cannot close, try cleaning the inside more. If you continue to have issues with it closing, I recommend you replace the AFM. Taking apart the AFM and cleaning it and reassembling it would only leave you with an AFM that opens and closes but calibration factory would be drastically off from factory spec.

With the AFM not closing, it would be sending your ECM an approx value of 1 volts when it would be expecting 0.5 volts. Max output is 4.8-5 volts (at fully open) This would throw off driveability and fuel/air mixture.

Might it have been tampered with in the past in attempt to fix drivability issues? Or is that avenue a lost cause?

You can expect a PM from me if I can't get it working properly.

[Gregs///M]

It depends. All the AFM's I see usually have some sort of "set" paste or glue to indicate whether the screw has been removed or not. If you feel your AFM was taken apart, adjusted, or modified, you can try setting it back to factory setting. This usually requires an exhaust gas analyser.

If you do experience drive ability issues, you can try adjusting while on the car but no guarantees that will actually work. When I refurbish AFM's, I do not accept or sell any that have been tampered with in this manner.

[paperplane94]

Sounds to me like the spring is too loose, i.e. somebody has tampered with it before.

As mentioned, you will need special scanning equipment in order to make your AFM give the ecu correct readings. Might be easier to start looking for a new or used AFM from another car with the same engine.

[JTDay]

Your right something is wrong with spring. I'm saving up for a new AFM. Thanks to all who provided guidance.