O2 sensor should remain connected and be up to operating temp for
monitoring output voltage. a high impedance volt meter (i.e., most digital
meters) must be used.

On Sun, 26 Apr 2009 11:41:29 -0600, Paul Connelly
<vanagonhummingbird@GMAIL.COM> wrote:

>Hi All,
>
>Seems like the only answer, but just thought I'd ask the accumulated
wisdom
>(after trawling the archives). 2.1 WBX Digifant '86.
>
>Well its Springtime in the Rockies and it was time to dig Hummingbird out
of
>her residential snowbank and dust her down for camping season... Started
up
>first turn - good sign. Put the house battery back in, and noticed that
the
>idle was rough and low. Looking at the tail pipe extremely rich. Tried to
>drive her round the block, and could only do so by switching the ignition
>off and back on again (can't go too far since the tire walls are cracked
and
>waiting for replacements to arrive). Checked the voltage output from the
O2
>sensor (disconnected) and just wildly varies from about .05V to
about .15V,
>nowhere near the .45V ish that it should be (or the .8V to be running that
>rich). While disconnected the idle was very high ~2000RPM, but was running
>smooth and leaner. Took her for a short twirl around the block and she
semed
>to be running fairly normally (as far as you can tell in a few blocks)
>except for the high idle. (I do live at 9,100' if that might make any
>difference to that)
>
>Tried resetting the memory in the control unit by switching off and
>disconnecting the O2 and grounding the RPM wire - no difference.
>
>So seems to be O2 is at least the most likely culprit. Does anyone have a
>part # for a FLAPS equivalent "splice in" for the Bosch, or the Bosch # so
>that I can try to source one locally. I would like to replace it and try
to
>get the first trip in next weekend, and would rather replace it than just
>leave it disconnected to get a better idea of how she is running overall.
>Don't have enough time to get one from the list vendors and get it fitted
by
>then. (We really only have Napa and CarQuest locally).
>
>As always, TIA for any and all advice.
>
>Best,
>
>Paul Connelly
>'86 Vanagon Syncro Westy (Hummingbird)