Date: Sun, 20 Mar 2016 22:29:45 -0400
Reply-To: Larry Alofs <lalofs@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@GMAIL.COM>
Subject: Re: Vanagon syndrome...it sucks!
In-Reply-To: <3F709CDE-5653-4BC2-B03E-34AB6C9A09EA@me.com>
Content-Type: text/plain; charset=UTF-8
Jason,
It might be worth checking the AFM with a meter. The procedure in the
Bentley is not really very informative. I would recommend checking the
sliding contact as follows:
Remove the AFM from the van so that you can move the vane inside with your
fingers. Connect a convenient source of voltage like a 9V battery to the
positive terminal (3) and the ground terminal (4). Connect your meter to
ground and the signal terminal (2).
Now move the vane inside the AFM slowly and smoothly thru its whole range
while watching the voltage on your meter. The voltage should change
smoothly and continuosly with no sudden drops to zero.
If you do see any breaks, the carbon track for the sliding contact is
worn thru in places and you could try opening up the AFM and moving the
circuit board a little on its mounting screws so that the slider follows a
slightly different path.
If there are no drops in the voltage during your test, that is a positive
sign, but the possiblity remains that the contact arm experiences a
resonant vibration at certain speeds which breaks the contact enough to
cause the ECU to become confused. This is the idea expressed in the
literature that originally described the classic "Vanagon Syndrome" Of
course the capacitor fix is supposed to be an economical way to remedy this
and I and others have had success with this in the past.
If you are convinced that the AFM is the problem, I would not hesitate to
try a capacitor 2 or 3 time as large as the commonly suggested one.
Have you verified that the Hall sensor and its connections are sound and
that the idle switch is adjusted and working well?
Good luck,
Larry A.
On Sun, Mar 20, 2016 at 9:58 PM, Jason Ellis <jason.ellis@me.com> wrote:
> Ok all, I've searched The Samba and tons of other websites for my issue.
> Maybe one of the gurus here can help.
>
> I have typical vanagon syndrome symptoms. Driving on highway for a while,
> then suddenly loss of power and bucking. Turn off engine, restart and all
> is good for an indeterminate amount of time. I did notice that just before
> (10 sec or so) the power loss starts, I seem to have a smoother running
> engine with a hair more power. I also had the syndrome start and I exited
> the freeway with very little power. I shifted into 3rd and it chugged a
> couple of times and the BAM, like a switch was turned on, the van power
> came back. Drove home another 30 min on highway with no problem.
>
> I have done the following:
> 35v 22uF capacitor between 2(+) & 4(-) on harness to AFM
> New fuel line, pump, filter, tank, and pressure regulator
> Refurbished, cleaned and flow tested injectors
> New alternator harness
>
> I have not cracked open AFM. I started to, but I didn't want to screw up
> anything.
>
> Any thoughts? Anyone have a spare good AFM I could test out? I hate to
> spend money on a AFM when I could be sourcing parts for either an engine
> swap or a Megasquirt setup. I'm at my wits end. I drove about 70 miles on
> Friday and during a 30mile stretch I had the syndrome pop up every 1/2 mile.
>
> Thanks for the help!
>
> Cheers,
> Jason Ellis
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