Date:         Mon, 25 Feb 2002 22:49:09 +0100
Reply-To:     Robert Steven Fish <fish@SALZBURG.CO.AT>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Robert Steven Fish <fish@SALZBURG.CO.AT>
Subject:      2.1 digifant MV engine Air Flow Sensor Wiring Harness 87 Vanagon
Content-Type: text/plain; charset="iso-8859-1"

Does anyone know the exact science on this "upgraded" modified wiring
harness #025-906-302 which gets installed between the air flow sensor, and
the old wiring harness connector?

Indicated in the tech bulletin is that "after prolonged driving at constant
speed the vehicle may on occasion experience a deterioation of
performance... hesitation or surging".

I had noticed that when driving at highway speeds, the power would seem to
just disappear, for a second or so, and then come back.   This coupled with
some rather insane idle "situations" leads me to believe that there is a
defective componant somewhere in the "idle / air flow / throttle" system.

Several years ago my Vanagon (1987) would start up normally, and almost
immediately, or at the first stop light,  would rev up (on idle) to around
2500-3000 RPM.. for no apparent reason. I would then turn it off, and start
it again, and usually, it would be fine idling normally at 800-1000... for
weeks.

Then came the highway scenarios... driving at full throttle (yes, in Europe
we are allowed to drive fast) If I would take my foot off the gas to down
shift, the engine speed would only go back down to like 3000 RPM and sit
there.. on the highway this was not so much of a problem.

Then it started doing this in the city.... and it was not much fun.  Every
traffic light, sitting there with my Vanagon idling at 3000 RPM.  Turning it
off, and then starting it again... only to have it surge up again within a
few seconds.

Then it started dying on me... my only guess was that it was now getting
flooded by this high idle, and I could not start it for 20 minutes or so
afterwards.. it would just crank... no spark... or drownded spark... or
something.

In order to get home from a grape harvest last fall, I disconnected the Idle
Stabilizer Valve.. and drove a few hundred miles this way.. but it still was
not happy.  I stopped for gas, and it would not start up... until 30 minutes
went by.

Long story short.   Now it will surge right up to 3000 RPM within seconds of
starting.. and if I am in a city driving situation, this means overheating
and constant key turning... not fun.

I have now gone through the components which I think can be causing this,
and have replaced the Idle Stabilizer Valve, the Idle Stabilizer Control
Unit, the Air Flow Sensor and am ready now to get this crazy modified wiring
harness.

My question... is this wire an important component, should I buy it, was it
determined by VW that the original harness was in fact defective (if so,
shouldn't they be passing these $100 wires away for free) ... and that is
why this part even exists?

Also... is there any way to get this part for less than 100 bucks?

And lastly... is there any other componant that I should be looking at,
besides perhaps the throttle switch, which would be responsible for pushing
the idle all over the place like this (Please do not suggest a new ECU... I
just replaced one in my golf and it cost a fortune!)

Thanks for any insights you all can provide!

RSF

PS... while testing the idle, I had the Vanagon running in my driveway at
idle... and I would then disconnect the idle stabilizor valve... and it
would go back down to a pleasant, normal idle.    As soon as I attached it
again... it rose to 2500.  I have two of these little creatures now, and
both hum and sound like they are actually working... I have two of
everything... air flow sensor, and idle stabilizor control unit... good
thing that eBay is around or I would be bankrupt by now!


<º)))>{   <º)))>{   <º)))>{   <º)))>{   <º)))>{   <º)))>{

Robert S. Fish
Salzburg, Austria
1987 Wolfsburg Vanagon 2.1 Weekender
1987 Golf Cabriolet
1991 Golf