Date:         Mon, 21 Nov 94 09:30:02 PST
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Lee Wood"        <Lee.Wood@forsythe.stanford.edu>
Subject:      Oxygen Sensor / Full Throttle Switch

I replaced by O2 sensor on my '81 Westphalia last week and used the
generic replacement part from my FLAPS (Auto Parts Club).  It was
*not quite* identical to the original; different numbers and
markings of course, slightly fewer slits and heavier gauge metal on
the part that inserts into the exhaust manifold, but other wise the
same.  The wire (single-wire installation) came with a crimp-on
connector already installed.  All I had to do was cut the old wire,
strip the end, insert it into the new connector and crimp it.
Voila!  It runs fine.  No real performance (term used loosely)
gains; I guess my fuel mileage will tell if there will be any
improvement.  The best part was that the generic sensor cost about
$26!

Of course getting the old one out was another story!  (details on
request, but the procedure involved a hammer and some cursing)

New topic...

Yesterday I was out playing in the engine compartment with my
multimeter and 12V test light and following the fuel injection
troubleshooting instructions in Haynes.  No real problems, just idle
hands.   ;p   When I tested the full-throttle switch on top of the
airflow sensor/throttle plate assembly, I couldn't get any results.
The ignition switch was on.  Haynes said to connect the test light
between the _uninsulated_ lead to the switch and ground, but both
leads were insulated.  So I tested both ways:  the light never came
on.  I can hear the switch click, but nothing happens.  Then I
tested the two leads connected to the switch (both white and the
same gauge) with the ignition switch on.  No power in either of
them.  All fuses are intact.  I can't decipher the Haynes wiring
diagrams (sure, like I could decipher _anybody's_).

My questions:

1.  Am I missing something here?  Should one of the two white wire
leads to/from the switch be hot with the ignition switch on?  Which
one, the front or rear (numbered 52 and 3, if I remember correctly)?
If so, are there any obvious places I should check for a short or
break?  Is now the time to break down and purchase a Bently manual?

2.  What does the full throttle switch _do_?  Do I need to fix it?
What's the worst that will happen if I don't?

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