AFM's question

[ChrisGadd]

My S3 decided to go jerky Joe on me in 3rd gear and the engine dies in 4th. I thought it might be a faulty Air Flow Meter (AFM) so decided to have a look at them. They seemed in good condition but I thought I would swap them over because I have read somewhere that only the top AFM is used by the ECU. Miraculously this has solved the problem and she now runs like a speeding bullet again. My question is .. If I had just swapped the leads would it have fixed the problem instead of swapping them over ?

[ceejay73]

Hi Chris, firstly, glad you got her running ok again. AFM wiring, the variable resistors connected to the flaps within the AFM's are both wired back to the ECU but the very sensitive hot wire thingy that can be found in the top of the air tract is only wired on the top AFM (presuming the plugs are still on the correct ones). In answer to your question, yes if you had just swapped the plugs from one AFM to the other you should get the same result, try swapping them back and see if the fault returns. If it does you could try cleaning the little wire thingy with an aerosol of carb cleaner or something similar, if you're tempted to try and wipe it do it very carefully with a cotton bud or similar they are fragile. It could be that the wirey thingy (I am sure it has a name but escapes me right now) is shot in that AFM, good job they carry a spare in the other innit. I personnally would probably mess around a bit just to satisfy my mind and try to deduce if it is bust or not but while the car is now running fine again I wouldn't spend more than half an hour or so..
The weather is improving, happy driving,
Carl.

Edit to add: Its easy to check which little wire thingy is connected, just pull the rubber boot back on the plugs, one will have 3 wires and the other will have 4.

>> Edited by ceejay73 on Wednesday 26th April 17:13

[Yellabelly]

You might want to try cleaning the wires, as stated use carb cleaner and cotton buds, you can see the before and after below and it does solve the problem without switching ADMs or cables.

[ChrisGadd]

Thanks for the advise chaps as always the contribution on the S forum is amazing