Does this sound like the dreaded problem to you:
Van runs fine when cold. After running for about 10 min.to 20 min. at highway speeds the engine bogs severely. It sputters at low rpm <4K. When you press the gas normally it almost does nothing. However, when you floor it and kick it into over drive (I have autmoatic) (ie when rpm are 4 or above and accelerating) the engine seems to engage fully and accelerate properly. When it drops below 4K rpm, it really sputters. It almost seems like half the engine is running constantly. It will only perform when floored and over 4K rpm and of course you cant run it like that. SOMETIMES, after turning it off, it runs fine for a while then does the same thing...eventually.
What has been done: The fuel pump and filter have been changed with the same negative results.
What year? (Guideline #3!) Vanagon syndrome is only applicable to Digifant systems per above posted tech bulliten. The symptoms you describe are similar if in a Digifant model as described above in the 5 Aug 2000 post.
One question,, does it clear itself by "resetting" by qucikly turning the key off and on while running? If so look at the threads regarding the O2 sensor. Sounds a bit like a problem I had and then cured with a new O2 sensor.
werner-max Junior Member Posted January 05, 2006 06:54 AM
HI, I m a new member and had a technical question posted earlier and can't find it anymore or any responses. Please help me re-direct my inquiry: [Moderator note: email blocked, unable to send courtesy message.]
I have an '87 Westfalia with now 127,000km and live in Calgary. The car runs great - except when hitting higher altitudes. Driving from here to Banff the car seems to get the hick-ups. Sometimes so bad I have to stop and watched the tach needle moving wildly until it seems to go down to normal idle speed. After a small rest stop the car drives OK again, but as long as I'm in the mountains the hick-ups coming back.
Some people recommended a new air-flow meter, a new oxygen sensor or a new fuel pump. Surely it must have something to do with hitting thinner air or the engine needing to work harder.
My mechanic cleaned the ECU grounds and adjusted the coast idle switch and now recommends replacing the wiring harness [parts#025-906-302-A]
Whenever I see a fellow Westy I talk to the driver, but so far my problem seems unique. Any suggestions - please...thank you ..Werner in
icarus Super Member Posted January 05, 2006 08:32 AM
Your post answers are in: electrical-vanagon syndrome.
If you do not have the updated wiring harness patch cord installed, I suggest that you install one. It would be rare not to have one at this late date. If you have one, trade it for a known good one.
While your altitude assumption has some merit, Banff is not very high as places go. Many places in Colo. are better than 8-10,000 ft. I suspect is is conincidental. Vanagan syndrome usualy happens after periods of extended running. The trip from Calgary to Banff for example might be long enough to induce the problem. The quick cure is to momentarily turn the key off and on again while the engine is running. This "resets" the computer. The other thing to look at it the O2 sensor. Read the posts there. I had similar problems that were cured by replacing the O2 sensor.
Read all the posts carefully, and remember that there are threads within threads, so the information that you are looking for may be hidden within the major catagories. Capt. Mike tries hard to keep the site clean and easy to navigate. If your post was cut, you should have recieved a e-mail telling you why.
Thanks Icarus for your help, Yes it sure sounds like the Vanagon-Syndrome. I ordered the new wiring harness and the O2 sensor too! Seems like a very common problem and I find it odd that some of the mechanics I talked too didn't know about it...thanks again...werner
Read the posts about the O2 sensor wiring harness problems. Often times, a short will develope in the harness where it plugs into the main harness. You can unplug the O2 sensor and run without it connected. The car will run in a default mode. If this cures the problem it tells you that the either the sensor or the sensor wiring harness is bad.
PS. I realize this should be posted in the O2 sensor thread, but since you may be chasing either problem,,,,,
Hoping to write in the right place. I have a 1991 Vanagon. We went on a trip and we used 47liters of fuel for 225 km!!! Actually the van will run fine for 10-15km and then loose power, emit black smoke, and no use in dowmnshifting, it will die off. I can restart immediately and every thing will be almost fine for 10-15 km. And again. I can just turn off the ignition and put it back on and the situation will be fine.
I had the car to the garage. They checked the O2 sensor, the harness, the air filter, the catalytic converter; the temperature sender was changed last fall.We then checked for loose grounds. They noticed that the AFM had been tempered with and that it could not be ajusted to specs. So we ended up changing the AFM and the van had never run so smooth...for 17km. Then it lost power, emitted black smoke and died. It restarted easily. I simply don't know were to look for. I would prefer not to be on a trial base all summer.
This is the Vanagon Syndrome topic -- per VW technical bulletin, No. 24-92-02, issued April 30, 1992. Symptom are similar but you didn't even tell us if you have the fix P/N 025 906 302 or attempted to change or test that fix part. This topic doesn't address the AFM but note that the fix makes the AFM work correctly, not the other way around. Missing or defective fix harness will not be corrected by changing the AFM.
New to the site, but Capt Mike, I think my harness has given up and is now time for a replacement. Who currently stocks the harness and what is now the current price. I orginally bought mine about 9 years ago for about $120.
Sorry, but someone had posted here that VanAgain was a source for these harnesses and I did check there and they don't list them anymore. I did find the harness on a couple of other parts sources, other than VW Canada, and it seems they have increased in price to about $330.
I have a 1991 Vanagon GL full camper with AT and about 155,000 miles. I've only had the van a few weeks and it has ran flawlessly - until yesterday. I recently went on a 900 mile road trip and returned home with no problems. When I went to start the van the next day it turned over, started, and idled very roughly and sporatically (400-2000 rpm) then it died. I tried starting it a few times with the same result. Sometimes it would start and sound ok - but then when I put it into gear it would die. I've read the posts on the Vanagon syndrom and I installed the replacement harness, but the same problem still exists. Any suggestions?
It's NOT Vanagon Syndrome. With Vanagon Syndrome, it ECU will reset, start and run fine for a period. See the factory tech bulletin in the first post in this topic that describes the symptoms. You have other FI problems covered by the other topics in this forum. Have you done any diagnostics per the Bentley or those topics?
Capt Mike, I know about the Vanagon syndrome as my 89 had it. With the advent of the AFM harness, these symptoms went away. Something that has just started is the engine will cut out occassionally, no backfiring, just complete loss of power. This will last a couple of seconds and it will kick back on again, or if I just pulled up to a stop, it will quit. When I restart, it is like nothing happened and it runs again. The harness, as I stated below, was installed about 9 years ago. Is this a resurrection of the Vanagon syndrome or do I have another problem.
Sounds like it. Did you do the tests VW published in the Tech Bulletin (also listed above this topic)? One other test is, when it does this, will it respond to full throttle? Most failures of the harness update will usually idle or run full throttle with nothing in between but smoke & bucking or die. Do this test on a back road w/o traffic! I've got a pic posted page 1 of my failure.