Date: Wed, 26 Aug 1998 19:42:30 -0400
Reply-To: Timothy Crooks <anc1cde@INJERSEY.INFI.NET>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: Timothy Crooks <anc1cde@INJERSEY.INFI.NET>
Subject: Re: O2 Sensor Questions
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Steve,
To answer some of your questions let me share with you what I know. I had a
symptom similar to yours, and found out a few things. Is your wiring harness to
your vane sensor/air flow sensor directly connected or is there a link of wire some
electronic stuff inside. There has been a problem with waterboxers since their
dawn and the symptom may go away for months at a time or come back. This link helps
it has a one way diode in it to help filter out some other signals in the doghaus
there. Mine had this problem, especially on very cold days after driving at very
high speeds for prolonged periods. If this is not the case, check the wiring
between your O2 sensor, (yes that cigarette shaped device in the cat) and where it
diconnects for adjusting. Whislt this may not be the problem itself, bear with me,
I am only landmarking structures. Now follow that wire up to the front of the eng
compartment and see where it goes into the main harness. Is it intact? Mine had a
weakpoint where it would have continuety and then not. I figured it out when I
accidently broke it off and the problem was very pronounced indeed! I had to cut
open the harness, try to bring out enough wire to strip, and solder it in place. I
then sealed in epoxy and she's held up great since then. Now if it is your sensor
let me tell you this and what it does.
Most of our Cali breteren are all to familiar with emission control devices. On
the newer Vanagons, like ours this device will monitor the O2 content of the
exhaust before it enters the cat. It will send a signal to the CPU which will send
a signal to the vane/air flow sensor to amke adjstments to the air/fuel ratio in
the engine. This hapeens very fast and is constant. Why replace it? Well federal
law says to to begin with. If your state has a IM programme and you get your ute
inspected, it will not pass if the O2 sensor is bad. Yes it will run, in fact
pretty good with it diconnected, but it will allow more HCO, CO and other free
organic compound to enter the air, and your cat. It will decrease the life of your
plugs and your cat. (Now I just read your post again and saw you added the vane
sensor harness link, so disregard the beginning of this reply, but it may help
others with a similar question).
Before you go back to the VW agency to sink a lot of $ into a new sensor,
realise there are less expensive after market products you can mail order in line.
Some of there are not Bosch custom and may require you to spice a bit, but the cost
savings is worth it. Try http://www.busdepot.com/, they have good prices. Another
choice is http://www.bus-boys.com/, but there are warnings about them at the
Vanagon Website. Godd luck to you. Anyone else have any ideas?
-Tim
1990 GL
Barnegat, NJ
Steven Johnson wrote:
> Greetings listees:
>
> I can hear what you're saying: "not another O2 sensor post!" But bear
> with me. I've tried to search the archives, but for some reason I keep
> failing.
>
> This has been an ongoing problem with my '87 Westy: I'll be driving down
> the road, van will suddenly lose power. It will idle, roughly, but will
> not accelerate. When I turn off the key, something "resets" and the van
> runs fine for a minute or two, but then will lose power and run roughly
> again. Clearly a fuel supply problem, but why?
>
> Things done:
>
> 1. new fuel pump and filter
> 2. another new fuel filter
> 3. auxiliary wiring harness for AFM installed
>
> After each of these "fixes," the van runs fine for a while (not a set
> period of time, just "a while.") In fact, after the aux. wiring harness
> for the AFM I thought the problem was solved; no stutters for over 2000
> miles. But, on my way to catch monster Alaskan rainbow trout last
> weekend, the same thing happens.
>
> So I (reluctantly) take it to my VW dealer (prior to this, I'd been
> dealing with my trusted local mechanic). Keep in mind that part of the
> problem is that, even without a "fix", the problem goes away, so the van
> is essentially running normally when I take it to a mechanic (i.e. after
> the stumbles this weekend, the van has run fine).
>
> The dealer mech interrupts me halfway through my explanation of symptoms
> and says "...and if you shut it off and start it up again it runs fine
> for about a minute or two?"
>
> "YES!!" I respond, elated that someone is familiar with the problem.
>
> "It's your O2 sensor," says the dealer mech.
>
> So here are my questions:
>
> 1. Is the O2 sensor that cylindrical object stuck into the end of the
> catalytic converter?
>
> 2. Where do you unplug it to replace it? I've traced the wired into the
> engine compartment and found what looks like a plug junction, but
> couldn't seperate the wires.
>
> 3. Can you run the engine without the O2 sensor? I ask for two reasons:
>
> a. I'd like to be able to unplug it next time it falters and see if the
> problem goes away, and
>
> b. If you can run it without it, what's my motivation for replacing
> it?
>
> 4. Ron advertises O2 sensors to replace mine that "require splicing".
> What's meant by this? The archives seem full of stories of spliced O2
> sensors that don't work. As someone who's not terribly technically
> proficient, I'm hesitant to attempt to solder and shrinkwrap a generic
> sensor.
>
> 5. Where's the best place to get a stock sensor? How much should I
> expect to pay? Is it relatively easy to install a stock sensor? It
> doesn't look like it would be a huge problem.
>
> Thanks for the info, people. Your advice and willingness to share it
> make owning a VW a much more pleasant experience.
>
> Steve
>
> Steve Johnson
> Anchorage, AK
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