Repairing a VAF

[93festiva]

Has anyone ever identified what actually fails when a VAF goes bad? Is there a specific component that can be replaced? If we just hit the boneyard for a replacement we are going to run out of them.

Bill

[kingstonpygmies]

I've wondered this too. I mean if people on the forum are smart enough and ambitious enough to re wrap wire on to a sending unit then surely someone has investigated the problems with the vaf.

Sent from Kingston Ga from my hillbilly handheld

[sketchman]

I've read that it's the POT track that wears out, and as that is the piece that takes probably 95+% of the wear, I'd say that's pretty accurate.

The VAF is really a simple thing. Stupid simple. It's just a POT with a huge lever(the flapper) controlling it. A fix should involve laying down new semiconductor material. What exactly that material is, IDK.

[93festiva]

Well if that is all there is to it, I am going go at fixing one. If it works out I'll post pics and parts used.

Bill

[bravekozak]

Go 93festiva go!

[bravekozak]

After you take a picture of it disassembled, let me know what parts we have to look for.

https://www.youtube.com/watch?v=Xkyfjo7spFc

[sketchman]

This sounds like the OEM method.

Conductive track potentiometers use conductive polymer resistor pastes that contain hard-wearing resins and polymers, solvents, and lubricant, in addition to the carbon that provides the conductive properties.

I broke open a VAF and it does look like a resin poured onto the surface of a PCB for the contact to ride on. How you'd get a hold of that stuff is beyond me. But the foil idea might do it.

EDIT: Fiberglass resin mixed with graphite powder and some kind of dry film lube powder perhaps?

[Rocketman]

The problem you'll run into is finding a replacement material with exactly the same resistance per inch as the OE material.

Maybe if you moved the wiper arm up or down 1/32" you might be able to contact fresh material and be good for for another lifetime of operation. IIRC the wiper only contacts a very narrow strip of the available material

[eurotiva]

I have a stack of b3 vafs. If Anyone needs one just ask


Stupid autocorrect. Thanks Tom V

[TominMO]

I have a stack of b3 vafs. If Antone needs one just ask

Who is Antone, and why can't he ask for himself?

[mystro]

Is there a way to bypass it altogether? That way it will basically just be an air cleaner?

[Rocketman]

Is there a way to bypass it altogether? That way it will basically just be an air cleaner?

yes, if you go to a standalone fuel injection system that uses speed-density or alpaha-n

[bravekozak]

Yes, change to a non-feeback carb. Presently, the output (three wires) from the VAF sends a signal to the ECA. Otherwise limp mode + you would have to either change the fuel pump relay to a single solenoid, or add a new hot source that says the engine isn't running.

[mystro]

sounds like i better stick with what I got haha

[93festiva]

Eurotiva,
Are they "good" vaf's?
If so I will gladly take them off your hands. You name the price.

Bill