Sorry.  Can't help, but please share any wisdom you gain from this exercise.
 //Jack

Date sent:              Tue, 7 Sep 2004 19:14:33 -0700
From:                   Tom Young <tomyoung1@COMCAST.NET>
Subject:                Do I need a HEATED O2 sensor?

> Hi all:
>
> For many years I've been using the O2 sensor in my California Vanagon to
> adjust the basic air/fuel mixture; that technique has worked fine.
>
> When I rebuilt my Federal Westfalia (no O2 sensor) I installed a
> water-cooled catalytic converter in the exhaust.  Since the water-cooled
> converter has the O2 sensor bung I figured I could install an O2 sensor here
> to adjust air/fuel mix.
>
> The first time I tried it I was getting readings so low (indicating "too
> lean") that I couldn't believe it; the van was running well and screwing the
> adjustment screw all the way in basically had no effect on the readings.
> Since I was using an new O2 sensor the only thing I could think of was that
> the O2 sensor wasn't getting hot enough as the catalytic converter has a much
> larger diameter than the crossover pipe, thereby cooling the mixture.
>
> Accordingly, I installed an 18mm spark plug "anti-fouling" device in the
> exhaust in the crossover pipe.  The only thing is, since the anti-fouling
> device is quite a bit longer than a standard O2 sensor bung (couldn't seem to
> find one locally) the O2 sensor's tip is not fully in the crossover pipe.
>
> Again, the readings I was getting from the O2 sensor (new sensor, remember)
> were extremely low.  Since I just failed my Smog today (too-high HC, too-high
> CO) I know these readings aren't correct.  Again, I'm *guessing* that the
> problem is that the O2 sensor isn't getting hot enough, since the tip is not
> fully in the flow of the exhaust.
>
> So, I'm thinking I should buy and install a *heated* O2 sensor; if my
> problem is that the single-wire sensor isn't getting hot enough, that should
> work, right?
>
> Or am I missing something else here?
>
> TIA.
> ---------------------------------------------------------------
> Tom Young                       '81 Vanagon
> Lafayette, CA 94549         '82 Westfalia
> ---------------------------------------------------------------