Date: Mon, 28 Mar 2011 10:34:33 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: engine dying while driving
In-Reply-To: <AANLkTimL3aQW1pSMU1q-s4O0nmSC3Qu3hqmXmgdTxSNa@mail.gmail.com>
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Joy,
vanagon syndrome is probaly one of the most mis diagnosed or understood issues out htere.
From the symptons I suggest that the oxygen sensor or circuitry is a problem. This can be easily diagnosed. When the event occures try full acceleration. If the throttle switches are working correctly full throttle turns off O2 sensor control. If you get full power at full throttle and then the sympton returs at part throttle you have an O2 sensor problem.
Another test is to cycle the ignition switch. Will the sysmton is occuring, keep foot on throttle steady and yes while still moving cycle the ignition off and back on. If power comes back for a while and then it acts up again you know for sure you have an O2 sensor issue.
Now why does this happen? If the sensor is weak, contaminated etc. output can dimininsh from not getting hot enough, getting road spalsh or even from cold weather especially during low load/speed conditons.
When the sensor signal is not suffecient the ECU continues to enrichen the mixture until that sensor feedback is there. The mixture will richen to the point of choking the engine and even making black smoke.
Since the sensor does not work immediatley after start up it is ignored even on a hot engine. That is why cycling the igniton will clear it. Same for full throttle.
The sensor should have a heat shield on it to help deflect wind and road debris. Most are missing.
Hope this helps.
Dennis
> Date: Sun, 27 Mar 2011 22:12:22 -0230
> From: jhecht@ALUM.MIT.EDU
> Subject: Re: engine dying while driving
> To: vanagon@GERRY.VANAGON.COM
>
> Other opinions? If the problem occurs often in urban driving, do you all
> agree that it probably isn't vanagon syndrome?
>
>
> Joy
>
> On Sun, Mar 27, 2011 at 9:57 PM, Richard Jones <jones@colorado.edu> wrote:
>
> > I disagree that this seems like classic vanagon syndrome.
> > Classic vanagon syndrome happens after steady pedal on the
> > highway for some extended period of time. Think level
> > interstate highway at 65 mph for 15 minutes.
> >
> > Urban or suburban driving syndrome is something else. When
> > she is going up a hill, she is applying pedal.
> >
> > I have a VW pigtail for sale, but I don't think Joy should
> > buy it. It would not cure her problem. Unfortunately, I don't
> > know what will, but I think the vanagon syndrome cure would be
> > a waste.
> >
> > Of course, she should have the cure because SOMEDAY she WILL
> > have vanagon syndrome. ;-)
> >
> > Richard
> >
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