Mweinst

I've been searching Google for a while now, and can't find a definitive answer to my question.

When testing my AFM, the voltage increases smoothly as I open the flap, with no skips or hiccups at all.

However, when I do the same test while checking the resistance, the numbers jump all over the place.

Is the resistance supposed to change in a smooth, linear fashion? If not, does this mean the AFM is bad?

I am feeling a slight hesitation several times through the rev range as I accelerate using part throttle. This happens from low RPMs to up around 4000 RPMs.

Any advice is welcome.

Tom M'Guinn

The resistance should also progress smoothly, but beware that many multimeters are not able to track rapid movements like that and will blank out or skip around until the reading settles in. You might try your multimeter on a known good potentiometer to see how it reacts before concluding the AFM is scratchy.

Mweinst

Thanks, Tom - I wouldn't have considered that my multimeter might be giving me a faulty reading. I'll have to see if I can get my hands on a good AFM to test it out.

I'm half hoping that the AFM is causing my issues, since it's an easy fix.

Tom M'Guinn

Could be for sure. But either your multimeter is smoothing out voltage jumps, or its creating phantom resistance jumps. Very unlikely that the voltage is actually smooth even though the resistance is jumpy. Most multimeters do a better job tracking moving resistance than moving voltage, so all things even I'd trust the scratchy resistance readings over the smooth voltage, but would want to know for sure before replacing the AFM. A $2 pot from Radio Shack would tell you...

odonnell

Get one of those crappy analog multimeters for $10 at walmart...they have a needle that physically moves. That will give you a better idea of how jumpy it is, for resistance (and a spare multimeter).

Mweinst

Forgive my inexperience with electronics, but how would I use the potentiometer to perform a test?

The analog meter is cheap and easy, as well. Anything that will tell me, for sure, if my AFM is good or bad works for me.

Mweinst

Never mind - I just figured out that you meant that I would test the multimeter.