Been there, done that--
I would strongly suggest that you remove the AFM ( not difficult ), clean it
up in some gas, remove the cover, and carefully examine the thing. The
little white resistance element is clearly visible, and wear is readily
apparent. As you can see when you examine the critter, the resistance
increases ( or decreases ) in steps, rather than in a continuous manner. I
would love to locate a source for these elements, which were manufactured by
Bournes, a company that specializes in variable resistors.  It is this
critical component which fails. The rest of this ( rather expensive ) unit
will last forever.
Chuck
'83 Westy
'84 XJ-6
----- Original Message -----
From: "Jeff Hammerstrom" <speakerdesign@MSN.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, July 10, 2003 3:52 PM
Subject: AFM resistance test

> Does anyone know what the resistance should look like as you move the air
> flat and measure between pins 2 and 3? Bently says the resistance will
vary
> but that's not much info. Is a linear or log progression? I know it's
never
> going to be closed while the engine's running so is there supposed to be a
> step in resistance as it moves from rest and then a progression until it
> fully opened? From what to what values? Any help here would be
appreciated,
> mine may be bad.
> Thanks