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
---------------------------------------------------------------