I concure that this problem is not a myth.   All due respect to DH.   But I
had a recurring problem of engine coughing and hesitation that I learned to
deal with by turning the engine off then back on again while still rolling
at highway speed in neutral.  I did this until I did the 22uf cap fix and
never experienced those symptoms again....

Steven
91 Westy
On Nov 26, 2011 10:04 AM, "Mike B" <mbucchino@charter.net> wrote:

> VW wouldnt have developed a wiring repair harness and installed them at
> their expense for a mythical problem.  Yes, I have experienced it, and
> corrected it permanently with this harness.  No myths there.
>
> Sent from my Verizon Wireless Phone
>
> Dave Mcneely <mcneely4@COX.NET> wrote:
>
> >Dennis, my van exhibited exactly the symptoms that are typically
> described as "Vanagon syndrome."  New AFM fixed it, period.  Now, that is
> more expensive than an oxygen sensor, but replacing an oxygen sensor that
> was not bad would not have fixed the problem.  Why do you say it is a
> "myth"?  Folks vehicles do behave that way given certain conditions.  If it
> is the oxygen sensor causing it, then so be it, but it was not in my case.
>  The oxygen sensor was good.
> >
> >mcneely
> >
> >---- Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
> >> In my opinion "Vanagon Syndrome" is a myth. It always comes down to an
> O2 sensor or circuit problem. Capacitors and active harness gizmos may
> slightly max or hide it but the problem is not fixed until that O2 sensor
> issue is corrected.
> >>
> >> One thing that never gets mentioned is the O2 sensor heater. You need
> to make sure it is working. You need to make sure that it is not open and
> that near 12 volts is there with it connected. I have seen wiring issues
> where the plug has 12 volts with the sensor disconnected but due to a bad
> wire in the harness it drops off once the sensor is plugged in.
> >>
> >> The sensor is almost like a battery. It works via a chemical reaction.
> I have witnessed the sensor working fine most of the time and then during a
> long trip it begins to fail to produce voltage. Run away rich here we come
> (the Syndrome). Stop for a while and then it works OK and after some time
> "it's happening again".
> >>
> >> The sensor placement is really in a bad location. It is not in a
> consistently hot part of the exhaust. It is exposed to a lot of cooling
> air. It's sprayed-contaminated with rain, salt, road dirt and everything
> else coming right off that left rear tire. What were they thinking? Then we
> add some poor wiring that corrodes and combine some grounds and it a wonder
> things work at all.
> >>
> >> The only Vanagon uniqueness here is how often it plagues us.
> >>
> >> Dennis
> >>
> >>
> >> -----Original Message-----
> >> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of David Hardy
> >> Sent: Friday, November 25, 2011 11:07 PM
> >> To: vanagon@GERRY.VANAGON.COM
> >> Subject: Re: vanagon syndrome strikes...advice?
> >>
> >> So a quick update...I unplugged the O2 sensor (thanks Angus) and the
> problem went away - so I changed out the sensor and she ran perfect all
> day. Maybe I had vanagon syndrome *and* bad O2 sensor...who knows...but we
> are back in happy camper-land.
> >> Love this list...
> >> David
> >>
> >> Sent from my Android
> >>
> >> John Meeks <vanagon@gmail.com> wrote:
> >>
> >> >David,
> >> >
> >> >Sounds like you've done all the right stuff to eliminate Vanagon
> >> >syndrome as the cause of your problems..
> >> >The first thing I thought after reading your diagnostic process was a
> >> >failing catalytic converter. Could cause those symptoms when the cat
> >> >gets hot.
> >> >
> >> >You might also check your voltages at the ECU per Bentley manual.
> >> >
> >> >John Meeks
> >> >'91 Vanagon MV
> >> >Northern Michigan
> >> >
> >> >Vanagon Rescue Squad
> >> >www.vanagonauts.com
> >> >
> >> >
> >> >
> >> >On Fri, Nov 25, 2011 at 10:14 AM, David Hardy <david@planetmind.net>
> wrote:
> >> >
> >> >> Long story short...left Colorado for New Mexico in my new-to-me 1990
> >> >> westy Sunday, when 2 hrs into the trip on I-25 I felt the dreaded
> >> >> single engine "buck" - one simple stumble, then another 20 minutes
> >> >> later, then another in
> >> >> 10 minutes...then every few minutes or so. By the time we got to
> >> >> Trinidad, she was stumbling pretty badly , but not bad enough to
> >> >> stall out. stumbling was *not* accompanied by tach needle drop, and
> >> >> seemed to do it when pressing accellerator after letting off. if I
> >> >> pushed the clutch in during an "episode", idle would be erratic,
> >> >> surging and sometimes dropping slowly to stall. hard to say whether
> >> >> turning ignition off/on made it go away, as condition was very
> intermittent.
> >> >>
> >> >> Next morning replaced fuel filter and put in some injector cleaner.
> >> >> One hour later down the highway, same deal.
> >> >>
> >> >> Got to Taos, read up and went to Radio Shack for a 22mf capacitor and
> >> >> a soldering iron. Also got a new cap and rotor and a set of spark
> >> >> plugs just in case. Installed the capacitor (electrolytic, didn't
> >> >> have a tantalum), and put in new cap and rotor. thought all was
> >> >> well...until about 2 hrs down the road from Taos to Albuquerque,
> >> >> syndrome returned but a little different...this time it was not
> >> >> stumbling, but hesitation - like a flat spot. pressing accelerator to
> >> >> floor seemed to make it "catch" and clear the condition, but it
> would return 2-5 min later.
> >> >>
> >> >> So I got back in and cleaned the resistive pad in the AFM w/alcohol,
> >> >> and loosened the screws that hold it's mounting plate and shifted it
> >> >> about 1/2mm to get the wiper on a new track. Ran perfect for about 30
> >> >> minutes on highway, but then it struck again and this time it was
> >> >> pretty severe hesitation - gas pedal wouldn't rev engine, no power,
> it would just cough.
> >> >> if I let it go to idle it would stall. turning off ignition and on
> >> >> again cleared it totally - for about 3 minutes.
> >> >>
> >> >> So I opened things up again and moved the plate back. installed new
> >> >> plug wires for the heck of it. Also got a new O2 sensor, but couldn't
> >> >> get the old one off. haven't had a chance to test it yet...kind of a
> >> >> pain to have to drive an hour to see if something fixed it.
> >> >>
> >> >> So, anyone have any recommendations? Also, does anyone know where I
> >> >> can get a replacement AFM in Albuquerque?
> >> >>
> >> >> David
> >> >>
> >> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> >> David Hardy
> >> >> Planetmind Internetworks
> >> >> Nedernet, Inc.
> >> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> >>
> >
> >--
> >David McNeely
>