Mr2 turbo - AFM Issues

Neil79 · 4 May 2009 at 19:46

I think its the AFM thats been causing my problems

I've just done a test according to the BGB

OLD AFM been in my shed for ages , it was replaced ages ago because the door kept on getting stuck

VS - E2 ( 390 )
VC - E2 ( 283 )
THA - E2 ( 3.22kohms )

Now this is the one on the car

VS - E2 ( NOTHING , 0 )
VC - E2 ( 285 )
THA - E2 ( 3.61 Kohms )

Any idea what VS-E2 controls? , because on my one its DEAD

Dogbreath · 4 May 2009 at 21:11

IIRC, VS is the wiper of the potentiometer inside the AFM, this is what actualy converts airflow to a voltage. An open circuit would suggest the resistance track is broken/worn out; since this is a sliding contact they do wear with age and this isn't an uncommon problem with flap type AFMs.

What happens to the VS-E2 resistance if you move the flap through it's operating range?

Neil79 · 4 May 2009 at 21:32

At first it did nothing , i had to give it a few taps... It then responded but the signal is all over the place and every time the flap door moved past a certain point it cut out. I left it for a few mins , came back and tested and again no readout at closed.

Compare that to the other afm from the shed , perfect readout at closed... perfect readout as you open the door flap (the number goes up) and then its the same everytime on fully open.

I've given the old afm a complete clean through also used wd40 so im going to put the one from the shed on the car tomorrow.. Its completely in spec so

The one from the car is a no go

Dogbreath · 4 May 2009 at 21:54

You can try prying the black plastic cover off the AFM to expose the resistance track, it will be obvious if it's badly worn. I have managed to rejuvenate them to some extent by repositing the wiper to use an unworn part of the resiatnce track, but it's easy to mess up the calibration if you aren't careful.