AFM 'rejuvenation' (for Digi owners)

[ryana89]

This applies to Digi owners with the barn door style, AFM (Air Flow Meter)

I had been experiencing very 'stepped' throttle for a while, then suddenly one night the car was undrivable.
It would lean out, jump, buck, loose all power then run super rich/lumpy.

Pulled AFM out of the car and put a multimetre across pins #2 and #3 (they're numbered on the plug) checking resistance over the entire span of the barn door movement (it should be linear and not jump up/down suddenly)

I got jumpy readings between 500ohms to 1.5K ohms, so off came the lid (it'll be stuck on well if this is the first time its been opened, just be patient, 'gentle' prying haha)



Below you can see the wear the resistive track accumulates over 350,000+ km.





Warning* DONT play with the spring tension, be very gentle with the swiper arm/track

I marked the two white wires to remember they're location.
From there diconnect the two white wire's and black wire (ground strap)

I've removed the plug in this pic too, keep reading.


From here, remove the 4 pin plug (circled red) held by 4 screws.


And out,


To remove the swiper arm, loosen the bolt circled yellow in the above pic,
and it should pull up/off.

Get a piece of paper and rub it on all the electrics contact surfaces/points. (Circled in Blue)
Use Isopropyl alcohol if you're really keen.




I spaced the swiper mechanism up with a piece of tape under the mechanism/on the barn door shaft.
From there I ever so gently, bent the swiper arm to a new shape so that it now contacts slightly lower on the resistive track.

Installation is the reverse, don't forget to re seal the lid if everything works out.
Here's a video of my end results, smooth increases/decreases in resistance values.



Someone else's video who explains it well,



Disclaimer*
This worked for me, it may not work for you.
This isn't a long term solution, but its good for fault diagnoses and getting a few more K's out of your old, slow, Digifant fuel injection.
Be very gentle on the internal electrics

[sports racer]

This might explain why my car runs a little bit rough under 3000 rpm but really sweet above it. Gets better fuel economy too over 3000.

Thanks for the detailed explanation.

Cheers

Paul