Easy enough to see of grounding is your problem... just clamp a big ol'
jumper cable to the metal sensor body, and the clamp the other end to a
solid body ground. If that temporary bypass steadies out your readings,
then the ol' rusty pipes may be interfering with your ground.

Remember that those pipes (and the rest of the engine) are in turn grounded
by the transmission ground strap, and the strap from the left head to the
body. unless at least one of these is in good shape, the engine (and hence
the pipes and the o2 sensor) won't be well grounded... and neither will the
rest of the FI system. Ideally, you want both of these grounds to be clean
and solid.

At 04:18 PM 2/15/2006 -0500, Geza Polony wrote:
>Hi all,
>
>I've been trying to sure an ongoing "intermittent power loss" problem (sound
>familiar?) on my '84 Westy and been messing with the O2 sensor. Replaced,
>rewired, etc.
>
>Questions: (a) is the ground on this ever a problem? Given that it has to
>pass through 21 year old tailpipes with rusted bolts, gaskets, etc. it seems
>that it might. Which leads me to question (b): is it possible to install a 4
>wire O2 sensor, with heater and ground wire, in place of the OE single wire
>sensor? Or at least a 2-wire?
>
>The reason I suspect grounding problems is that I installed Ken Lewis'
>monitor on the dash (thanks Ken!) and it's reading all across the board,
>from very low voltage to very high. Replacing the sensor helped but didn't
>steady the voltage to within limits. All connections are soldered, and I
>verified that the sheathing isn't touching the center wire.
>
>TIA