Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (October 1999, week 1)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Mon, 4 Oct 1999 16:03:14 +0200
Reply-To:     Darie Duclos <Darie.Duclos@UNIFR.CH>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Darie Duclos <Darie.Duclos@UNIFR.CH>
Subject:      1/4 mile syndrome is back!
Content-Type: text/plain; charset=us-ascii

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


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.