I wasn't aware that this was how the idle mixture screw worked. You CAN
adjust the sensor spring. Dan Hogue (sp?) has a detailed description of how
to do this in the Vanagon archives. By turning the spring adjsutment two to
three notches tighter he was able to bring  emissions down considerably at
idle. I have done this and tested it in a crude way and it does work. The
simple test consisted of "measuring" the soot output at the tailpipe given a
"loose" adjustment" and a "tight" adjustment. You have to fiddle with the
spring a bit and make sure you don't lose the initial adjustment position
otherwise you won't know what your baseline is in the event that you need to
start fresh. BTW I would be very interested in knowing what the initial
tension is on your system (that is - how tightly wound the spring is from 0
tension). Please fill me in on your progress.

You can also adjust the way the potentiometer arm tracks by adjusting it as
well...

DC
David Carment
NPSIA
1125 Colonel By Drive
Carleton University
Ottawa, Ont
K1S 5B6
v 613-520-2600 (6662)
f  613-520-2889