Date: Sun, 16 May 2010 11:41:52 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: 91 Carat has the highway hick ups
In-Reply-To: <131001caf146$57e79540$6401a8c0@PROSPERITY>
Content-Type: text/plain; charset="US-ASCII"
While disconnecting the sensor can be a test, if there is a short between
the sense wire and shield or the ground reference is bad, the problem can
still be there.
As for the sensor cooling theory my '87 is doing that now. Repeatable on
colder mornings. From the factory the sensors had heat shields and the 1.9L
engines had insulation over the sensor. As for air flow I do not know of any
other vehicle with the O2 sensor located behind a rear tire. Also, most
primary O2 sensors are located directly in the exhaust manifold, Not in a
Cat just before the final muffler. VW goofed here. And the O2 sensor heaters
do go bad.
Dennis
-----Original Message-----
From: Scott Daniel - Turbovans [mailto:scottdaniel@turbovans.com]
Sent: Tuesday, May 11, 2010 4:13 PM
To: Dennis Haynes; vanagon@GERRY.VANAGON.COM
Subject: Re: 91 Carat has the highway hick ups
very good point,
of course the O2 sensor should always be considered.
also a fine test is to just unplug it. Vanagons run surprisingly well with
it disconnected, not that I recommend that.
but it's a useful test to take the 02 out of the picture..
as for air flow causing 02 sensors to get too cool while driving ...
well, first, speaking of heated or non-heated 02 sensors ?
and secondly ..
there are countless cars and car designs where the 02 sensor is exposed to
air flow, and they don't have problems, so I'm a little skeptical on that
one.
Scott
----- Original Message -----
From: "Dennis Haynes" <d23haynes57@hotmail.com>
To: "'Scott Daniel - Turbovans'" <scottdaniel@TURBOVANS.COM>;
<vanagon@GERRY.VANAGON.COM>
Sent: Monday, May 10, 2010 8:40 PM
Subject: RE: 91 Carat has the highway hick ups
> Most "Vanagon Syndrome" and poor running during extended drives is miss
> diagnosed, especially by VW. They are almost always related to the O2
> sensor. The sensor is in a bad location subjected to a lot of wind cooling
> and road debris. After extended driving at speed the cooling can reduce
> the
> output and the ECU can start over-richening the mixture looking for that
> signal. At some point rich enough to cause running problems. Often the
> first
> signs of a bad or weak sensor is fast idle during cold weather or just
> after
> highway travel. The test! Cycle the ignition switch of floor the
> accelerator. If either clears up the problem for a short while, O2 sensor
> is
> the issue. Note that the O2 sensors originally had a heat shield or
> insulation on them.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Scott Daniel - Turbovans
> Sent: Monday, May 10, 2010 4:13 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: 91 Carat has the highway hick ups
>
> the text below that starts ...'you are on a longer trip'...
> and describes bucking, loss of power, and after a restart it's fine ...
>
> that is about "Vanagon Syndrome" and there is an adapter harness fix for
> that. it's not the AFM itself. And your 2.1 waterboxer should have that
> special adapter harness fitted in any case.
>
> however, for minor hiccupping ...
> that is distinctly a characteristic of an AFM that is badly worn in one
> spot
> where the wiper arm contacts what it rubs on inside the AFM.
> there are tricks to overcome that which you can read about online in
> several
> places I'm sure......but the real normal fix is a new or rebuilt AFM.
>
> it could be other things ..but 'usually' ..and for sure ...
> unexplained minor hiccups ( good word to describe it btw ) ....AFM baby.
> "usually." .
>
> Scott
> www.turobavans.com
>
>
> ----- Original Message -----
> From: "georgejoann@juno.com" <georgejoann@JUNO.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Monday, May 10, 2010 7:28 AM
> Subject: Re: 91 Carat has the highway hick ups
>
>
> If it's acting like the description below, the trouble may be in the AFM.
> Try a google lookup on vanagon syndrome.
>
> Copied from first entry:
>
>>> You are on a longer trip, the wasserboxer has been humming along for
>>> several hours and runs really good. Then all of a sudden,
>>> out-of-the-blue, the engine cuts out. The vanagon lurches, loses power,
>>> and starts bucking. You pull over and shut it off. A little later, you
>>> restart the motor, and it runs just fine. Sometimes this might not
>>> happen again for a long time, or if you are not so lucky, the vanagon
>>> might start this syndrome all over again after only a few minutes of
>>> driving. Sometimes the cutting out is very slight, barely
>>> noticeable...<<
>
> George/ATL
>
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