Darie, I have had a similar problem with my '84DL.  In my case, I have (with
the help of my mechanic) to the connector between the ECU and the FI wiring
harness.  If these contacts are anything but squeaky clean, I have problems.
Last week, I had problems restarting van after a short drive.  If I went
back to the engine, wiggled the connector a couple of times, it would start
right up.  No wiggle, no start.

John in Middle Georgia
'84DL

----- Original Message -----
From: Darie Duclos <Darie.Duclos@UNIFR.CH>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, October 04, 1999 10:03 AM
Subject: 1/4 mile syndrome is back!

> Help!
>
> I thought this problem had gone away, but now that I've got
> road inspection this week, it turns out it's not solved. I
> have a pretty good description of the symptoms now. Perhaps
> you can help me narrow down the possibilities.
>
> The problem: accelerator pedal begins to have little or no
> effect on propelling the vehicle forward. When the speed
> has dropped sufficiently, the engine hiccups forward, as
> if I wasn't giving enough gas. The RPMs go down, so it's not
> something like the clutch slipping. It may feel like it's
> running of fewer cylinders. Without even stopping, I can
> turn off the ignition and right back on, and the acceleration
> is back for 1/4 to a 1/2 mile, then the same thing happens
> again.
>
> Important details:
> - when engine is cold, no problem, I can start it up and
>   drive with no apparent time limit so long as I don't turn
>   it off.
>
> - each time (3 or 4 times) the engine was running between
>   10 and 30 minutes, then *was cut and started again* (with or
>   without much of a pause), the problem occurred: I had to
>   cut the ignition and restart every 1/4 mile until my
>   destination.
>
> - after a *45* minute drive (from cold start of course),
>   cutting the engine and starting again several times, with
>   varying delays, did *not* reproduce the problem.
>
> - arg! I just tried to reproduce the problem again by driving
>   5 minutes and shutting off the engine, then restarting.
>   It won't do it! It only does it when I really want to
>   go somewhere!! Damn piece of merde.
>
> - the engine is running much too rich. (At least) when it has
>   the problem, it spits out coal, enough to make a serious
>   black stain on the pavement or on your pants if you're standing
>   behind the bus.
>
> - a car electrician just checked some values related to the
>   temperature sensor. He found that at 40 degrees it read
>   1200 somethings (ohms? I can't remember) but he couldn't
>   find my model of bus in his references and he didn't know
>   for sure whether this value was normal. I left him my
>   Haynes manual but I don't know if it's in there. Anybody
>   know what this value means and what it should be for an
>   86 2.1 liter water-cooled vanagon (MV)?
>
> The only thing for sure about this problem is that it has never
> occurred on a first run after cold start. It has only happened
> upon starting up the engine when already warm. And then, if it
> starts doing it, it does it at every startup. If it doesn't do it,
> it doesn't do it at all no matter how many times I restart.
> The following possible causes had been
> suggested after my previous postings. I would like some opinions
> about which could be ruled out because I have very little time
> until the inspection and I'm afraid that if I take it to a garage
> it will cost me an arm and a leg before they even figure out what's
> wrong.
>
> - fuel pressure (pump or regulator)
>   I changed the fuel filter with no effect. How can I test the
>   pump or regulator?
>   Wouldn't this cause a problem upon a cold startup or during
>   an initial run?
>
> - bad O2 sensor
>   We disconnected and reconnected the O2 sensor once, before the
>   45 minute test drive, to see how the bus ran. Then we tried to
>   reproduce the problem with the intention of disconnecting the
>   O2 sensor at that time and see if the situation improved.
>   Unfortunately, after driving 45 minutes, the problem did not
>   occur.. I plan to try this after a shorter drive, but I'm not
>   sure what I should expect. i.e. it's runs bad, I disconnect the
>   O2 sensor, it runs better? Some of you said it wouldn't run very
>   well with the O2 sensor disconnected so how do I tell the difference?
>
> - bad temp II sensor
>   Would this not cause a problem even without cutting the engine,
>   simply just when the motor gets warm?
>   I can see how some of these things would get reset upon restarting
>   the engine and I heard that their values are ignored by the
>   "computer" for a little while after startup, but I don't see why
>   they shouldn't affect the "first run" after the motor has gotten
>   warm.
>
> - grounded O2 sensor circuit, loose or disconnected O2 sensor ground
>   I may have twiddled it both times when the problem could not
>   be reproduced. How could I check for sure that this is the
>   cause? I guess the car electrician could do something with
>   measurement instruments but I have to reproduce the damn problem
>   for him, which I just failed to be able to do.
>
> - clogged catalytic converter
>   Shouldn't the problem be more constant then?
>
> - faulty ignition switch
>   Is it dependent on the warmth of the motor?
>
> - gas cap plugged up
>   my gas cap is not ventilated, but maybe some other ventilation
>   is plugged up. However, the pattern of the symptoms speaks
>   against it again.
>
> If you can help me narrow down the possible causes, I would be
> very thankful. Also, if you can point me to the procedure for
> incriminating or innocenting one or the other component, that
> would be great.
>
> I'm kind of on my own (swf) to do this now since I moved out of
> the pretty-good-with-mechanics-boyfriend's place yesterday. I'm
> not very experienced but I can do anything I'm told. (Hey, I changed
> my pilot bearing a few years back with your help..) And I've got my
> Haynes manual..
>
> Thanks a bunch!
> Darie
> '86 multicolour canadian Westy with swiss landed immigrant status