I'm likely confused, but... I thought an oxy. senser reading around 0.8
or 0.9 volt, (high), indicates a rich mix, and a CO reading of say 1.5
and above, at sea level, would indicate a rich mix also?  If this is not
confused, your readings were in agreement and indicated too rich.

-Dana-

Jonathan Hess wrote:
>
>     This happened to me once and I put it on an exhaust analyzer trying to
> figure out what was going on.  The O2 readings and CO readings were both very
> high!! Highly irregular having a rich indicator and a lean indicator. This
> brought me to the fact that the ECM was firing injectors erratically.  After
> removing the ECM harness @ the ECM, I started measuring all the resistance
> values according to the Bentley manual. Bingo pin 19!!!   This wire runs
> along the O2 sensor signal wire and acts as a "shield" against RFI according
> to the diagram supplied by Bentley. It seems to me it also acts as a ground
> for the ECM cause when it doesn't have a good ground with the block (.3ohms
> or less) then the engine will not operate under any kind of load unless you
> turn the ignition off and restart which will only buy you time (2-3 minutes.)
> The reason this happens is when the ECM goes into "closed loop" it relies on
> the O2 sensor and that particular ground for dependable signal. My guess is
> that under open loop, those signals are ignored, hence ok drivability. The
> fix for me was to relocate that ground from a bakelite housing to a nice
> metal distributor a couple inches away. I haven't had any troubles with mine
> since that occurence.  Just an idea, I think this ground location is very
> succeptible to intermittent opens in the circuit due to its location and may
> just fix your van and make you realize that these things aren't that comlpex
> after all. Eurovans on the other hand. Anyone ever replaced a clutch or
> performed head-work on one of those things?? Wow
> Anyways good luck.
> -Jon Hess
> 91 Syncro
> 66 Beetle