Date: Sat, 7 Feb 2009 19:07:00 -0500
Reply-To: pdooley <psdooley@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: pdooley <psdooley@VERIZON.NET>
Subject: Re: A New Perspective on Vanagon Syndrome
In-Reply-To: <3318.192.168.0.144.1234049652.squirrel@hasenwerk.homeip.net>
Content-type: text/plain; charset=iso-8859-1
Probably discussed before, but the *real* fix is to replace the AFM with a
MAF.
Figure out the output signal profile of the AFM and build an interpolator to
plug into the MAF.
I just did a little research and discovered a Ford Tempo/Topaz/Ranger MAF
can be purchased for $75 new, as little as $20 shipped used on Ebay.
Heck, I saw a used one for $10 on CL.
All we need is the interpolator.
However, this probably won't happen since AFM's from Golf/Jettas will
interchange with Vanagons and the rest of the crowd is doing/done engine
swaps.
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David Marshall
Sent: Saturday, February 07, 2009 6:34 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: A New Perspective on Vanagon Syndrome
The issue here is the pigtail isn't a cure for the problem rather a mask.
All the pigtail is does as act like a capacitor between the
AFM and ECU, so when the signal drops out the pigtail keeps the signal
more or less constant instead of dropping out. It is when the signal
rapidly goes from something to nothing where the ECU gets confused.
The real isssue is the AFM. If you remove the plastic cover
you will see there is a resistive pad that some arms sweep over. If
you look at these pads you will see the arm has worn right on thru.
Putting the capacitors on will solve that problem for a while, but after a
while the worn out spots get bigger and bigger and soon the capacitor
can't keep up.
What I always do is tweak the arm a little bit
so it runs on a new track and the problem is solved for the next few years
until it wears thru that location. I think this is part of the
reason why they switched over to MAFs on the later vehicles as there are
no moving parts.
David Marshall
VW Adventure Driver and
BMW Adventure Rider
http://www.hasenwerk.ca
On Sat,
February 7, 2009 12:17, Loren Busch wrote:
>
> This is
the second of the promised posts about Things Learned on the Road.
>
> I'm going to talk about 'Vanagon Syndrome' or as VW
called it
> 'Intermittent'
> driving problems.
>
> There is a lesson here. NOT ALL VANAGON SYNDROME SYMTOMS ARE
THE SAME.
>
> Those who have been on these lists for any
time have seen at least one
> reference to 'Vanagon Syndrome' but
let me describe it the best I can from
> my experience. (Also see
the links at the bottom of this post) I had one
> occurrence in
my '85 in the middle of nowhere in Utah. After driving for
> some
time at a steady speed the van felt like it had been hit by a 90 mph
> headwind, total loss of power (but engine still running) and
erratic
> response from the gas pedal. Pulled to the side of the
road, turned off
> the
> ignition, restarted and no
problem for another few miles then wham, same
> thing again. Shut
off and restarted again and never had the problem
> reoccur
> up to the time I totaled the '85 a few months later. I acquired my
'90
> Westy in Jan 2002 and have now put just under 50,000 miles
on it (total at
> 142,000 now) and most of that mileage on long
trips. And not a hint of
> Vanagon Syndrome until on the way to
BBTB last month. But this is where I
> learned that Vanagon
Syndrome has more than one form. Pulling out of
> Susanville and
heading down Hwy 395 toward Reno I started getting a slight
>
miss/loss of power/hesitation. It would come and go. Didn't bring me
to
> a
> halt at all and I could still maintain speed,
around 60-65. I started
> thinking about looking for a shop in
Reno but the problem stopped as we
> approached Reno. How do you
troubleshoot a problem when it's not being a
> problem? So we
continued on. I was traveling with Bob Peak from
> Portland,
> he was driving his Subie powered Syncro Weekender (don't ask
about
> climbing
> hills with a 2.1L while running with a
Subie powered Vanagon, I don't want
> to talk about it). After
passing through Reno my van started to act up
> again. Not enough
to even slow me down, not the complete loss of power
> I'd
> experienced in the '85, but very worrisome anyway. Bob suggested
shutting
> off and restarting to see if the ECU would reset and
that worked. I did
> that a couple of times and always got good
running, for a while, after the
> 'turn off restart' cycle. This
confirmed that I was most likely dealing
> with a bad signal going
to the ECU and most likely from the AFM. That
> night
> we
stopped in Lone Pine and in the morning I dug into the spares cache for
> an item I'd acquired a couple of years ago from a list member,
the
> infamous
> Vanagon Syndrome Pigtail that plugs in
between the AFM and the cable that
> goes to the ECU. And the
problem was cured, not another glitch for the
> next
>
nearly 3,000 miles until I got home.
>
> So, add this
info to the lexicon of info on Vanagon Syndrome. First, you
> may
not get COMPLETE loss of power but can get just a miss or hesitation.
> This was new information for me. Second, the VW 'pigtail'
works.
>
> The one thing I didn't do that I should have,
and will, is remove the
> pigtail and drive for a while to see if
the problem returns. That would
> confirm the diagnosis. I'll do
this because if I was dealing with nothing
> more than a poor
connection between the AFM and the cable that could have
> been
cured by simply unplugging and reconnecting the cables.
>
> And don't get me wrong on this. NOT ALL RUNNING PROBLEMS ARE
VANAGON
> SYNDROME!!. Bad or dirty grounds will give similar
symptoms and I'm told
> that a misbehaving Temp 2 sensor (not
failed completely) can give problems
> like this. This post is
intended to show, based on my experience, that
> Vanagon Syndrome
can be mild or severe, YMMV.
>
> Footnote: For more info
in Vanagon Intermittent Syndrome see
>
http://www.geocities.com/harald_nancy/intermitt._syndrome.htm
>
> And that link includes info on a fix that works for many. BTW,
if you
> want
> to try the capacitor fix you can add the
capacitor to the connections in
> the
> external plug as
well as the method shown.
>
> And even more info here
complete with the VW write-up:
>
>
http://www.telusplanet.net/public/gary2a/rack/afmharness/afmharness.htm
>
