Date: Mon, 10 Oct 1994 09:39:32 -0700
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Edward Wilson <ed@sun-valley.stanford.edu>
Subject: Digifant problems - uneven running
Hi,
I'm having some problems with my girlfriend's '92 Golf (Digifant II
Fuel injection), that seem to be almost the same as my Dad is having
with his '90 Vanagon.
Problem: The car was running fine, we had been on the freeway for ~45
minutes, then suddenly it started to stumble (as if the fuel were being
cut off), we turned around and made it home - it seemed to run better
the faster we went (3500 rpm+), but would still stumble every few
seconds. The car is barely driveable at lower rpm. With the car
stopped, and out of gear, if I hold my foot on the gas at a fixed
point, the rpms will vary chaotically from idle to 2500.
It had done the exact same thing 2 weeks ago, just as we arrived at
Lake Tahoe (~6000 feet elevation), so I changed the fuel filter (didn't
seem too dirty), and the problem gradually went away after about 5
miles of driving. I thought it was solved, until now.
My dad's problem: My parents just finished driving from Pennsylvania
to Washington State, and they had some trouble going through Wyoming at
4000 foot elevation. They went through the same drill as I did:
problem happened, change fuel filter, problem goes away, several
hundred miles down the road (still in Wyoming - it's pretty big), the
problem shows up again. Fortunately, they found someone who knew about
VWs, and he asked my Dad if they had "a resistor". My dad said he
didn't think so, so they explained what it is:
VW part number 025 906 302 A - costs $95 (in Wyoming).
This is a wiring harness with a male connector on one end, and female
on the other that attaches to the air flow sensor (in-line with the
existing circuit). The mechanic said that almost all the Vanagons in
the area had this (due to high altitude?). My Dad drove the bus until
the problem showed up, pulled over, slapped this in, and it went away,
so he's convinced it works. Does anyone out there have this
"resistor", or have any clues?
Last night, I looked in the Haynes manual, and found that the Air Flow
sensor has four connections (for two signals) - one signal is the angle
of the flap -> air flow, the other signal is the air temperature. Both
signals are in the form of a variable resistance. I can guess that
this added "resistor" either adds to the signal, reduces it, or
bypasses the sensor altogether.
Also, the Golf is ~30 months and 31,000 miles old. Should this stuff
be covered under warranty? I guess the question is, "_Is_ it covered?"
Thanks in advance for any help,
Ed Wilson
Aerospace Robotics Laboratory Email: ed@sun-valley.stanford.edu
Aero/Astro Department Lab: (Durand 010B) 415-725-3293
Durand Bldg, Stanford University Office: (Durand 013) 415-723-1260
Stanford, CA 94305 FAX: 415-725-3377
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