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)