Vanagon Syndrome -- Air Flow Meter fix


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Yes I have read those posts on KennComm; however, GoWesty is offering a rebuilt AFM with the harness included. I was wondering if this is just the jury rigged thing I have read about where they connect a resister between the #2 and #4 pins in the AFM.


New member
Capt Mike, I just replaced my AFM and the harness with new; however, the syndrome is still happening. What now? O2 sensor? ECU?

Capt. Mike

The O² sensor is easy enough to test. And the cheapest to replace. How long has it been -- they should be changed every 60K (early models) to 90K (late models)? Generic substitutes are OK since they are all Bosch patent licensed. See the O² Sensor topic.

I wouldn't replace the ECU until you have tested EVERYTHING else -- sensors and all, even if they don't seem related. FI does weird things and is very sensative to the grounds.
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New member
Okay Capt Mike, the O2 sensor has been replaced and the engine still stalls and quits, normally at lower RPM. The van is certainly peppier and really wants to go now, so the O2 sensor replacement was required. After the AFM and harness change, there were times when the engine quit, but it took awhile to get the engine to start again. A little background - this started after I used some injector cleaner as the engine was sluggish and I was hoping to clean it up, I did this again twice, as the engine had started to quit and I thought maybe it was fuel/injector related (engine has 190,000KMs on it). The engine did suffer from the syndrome right from new and VAG (I was living in Germany at the time) could not solve the problem (1989 model CDN spec). The AFM harness solved my problems for about 10 years, now this. My mechanic says that the fuel pump shuts off every once in awhile, but there is still pressure in the lines when it does. As I stated, the engine seems to quit while slowing down or at the lower RPM; however, it has happened at higher RPM, but the engine kicks back on again very quickly (even though I have the auto trans). My mechanic says he used a diagnostic system and there were no discrepancies that he could see. As it displayed the classic symptoms of the Vanagon syndrome, I assumed it had returned. Where do you think I should proceed to next????


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Capt Mike, I've been monitoring the situation and it appears that the engine quitting is happening now in the first 4-5 minutes after a start and then it runs okay. It sometimes quits twice, almost in a row, but after that, it runs smoothly. After each quit, it starts right up after I recycle the ignition switch (without using the starter, even with the auto tranny - i.e. jump start). Is this now a fuel related problem or still a Vanagon syndrome situation?

Capt. Mike

What changes at the 4-5 minute mark? Temperature of engine. This is where to start looking -- temp senders and the related controls. This IS NOT a Vanagon Syndrome problem for this topic. For FI engines, the FUEL SYSTEM topic on this site stops when it enters the FI system. FI "Start/restart or stalling" has its own topic when you've established you have fuel to the FI system. But if your fuel pump is intermittent, residual pressure will not let the engine keep running.
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1986 vanagon hesitation problems. Recently I replaced my O2 sensor and coolant sensor in my 1986 2.1 liter. Previous to this, the van ran without any major problems. It look as if this was the first time these sensor have been replaced. (180k+)

Upon this something major happened. The van started to immediately act up after driving the van for 2-3 minutes; it would suddenly bogg out and won't exceed 3k RPMs. Though after shutting of the motor and immediately restarting it, the van would run fine for another 2-3 minutes and then finally bogg down again.

I tried the following things but have had no luck solving the "out-of-the-blue problem:

>Unplugged O2 sensor
>Unplugged the Air Flow meter
>Unplugged both the 02 sensor and Air Flow Meter
>Replaced the fuel filter
>Remove the Air Flow Meter lid and clean compartment with Electronic Cleaner
>Checked over the ignition system wires (rotor, spark plugs and wires, etc.)

After doing all of these things I still have no clue what is causing the motor to bogg down after a short distance of driving. Should I solder the transfor to the #2 and #4 ports inside the Air Flow Meter? During those 2-3 minutes that motors prrrrs like a kitten. Please email me with your suggestions.

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Capt. Mike

See post #3 on page 1 of this forum, 8/5/2000. These are classic symptoms of Vanagon Syndrome. Unplugging parts of the FI aren't likely to make it run better. :rolleyes: Run the troubleshooting tests specified in the Bentley §24.43 & §24.61 to diagnose FI failures. There is a separate topic in this forum discussing those tests with a volt-ohm meter. (Guideline #4) DON'T ruin an AFM experimenting; you haven't even tested it!
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New member
Dear Captain Mike,

my van, which i love, was insisting that it doing over 100 kmh (60mph) was too hard. bucking and hesitating blah blah blah... i changed the whole fuel delivery system (save the injectors, which are yellow) and it continued to do that thing it does.
it got under my skin, and i ended up here.

i was inspired, after reading all the info in this thread, and i pried open my air flow sensor cap.
inside i found a spring wheel with the number 500 printed on it, and a little copper lead that drags on a black conduction strip.
feeling good about what I'd read, i concluded that years make springs weak, and that dragging grooves into a thin conduction strip make bad bed fellows.
so i bent the copper leads to a tight fit, and turned the spring coil to increase the tension..
after 9 or 10 trips onto the highway i discovered that the tension on the spring coil (that allows air into the throttle body by resistance) made the biggest difference, and i had almost eliminated the hesitation and bucking completely...

so, to the point. is it possible that what was considered a design flaw on Bosch's part, in the mass air sensor itself, could actually be designed and intended for the purpose that it should be tightened during it's lifespan?
and if so, is there a spec that exists? or will it all be trial and error?

in my case i gradually wound it tighter and it improved the performance until i went TOO tight and it simply stalled when the idle switch kicked in.....

i would love some feedback from anyone who knows more about this than me.
sorry about the epic post. it seemed necessary.


[Moderator Note: What year, model? Guideline #3!]

Sorry Mike,

my van is a 1988 Vanagon GL. It has 247k on it and it looks pretty sharp.
more specifically to what i did to remedy the van syndrome, i'll break it down here...
i checked all sensors involved in vehicle function (save the power steering switch) and replaced the oil pressure senders and the water temp sensors. the idle switch was working but the spring on the throttle body was a bit weak so i attached a 40 cent spring to make sure it came all the way back to clicking on territory. i then sprayed white lithium greaseinto all the sensor recepticles to help the connectivity of every coupler on the block. fuel injectors, o2, random things etc.
then i pried the top off the MAF. like i said in the other post i fiddled around with it, but i actually have an update.

go through this process when the engine is cold.

start the engine and while it's idling, loosen the hex head screw and rotate that little spring wheel whatever direction you need to to get the engine idling as smoothly for you as it will. you'll hear it change as you move the nodes on the contact strip. when you've found the sweet spot, reattach the little piece of retaining wire to the wheel cog.

i drove my van 400 k over hills, towing a trailer, without a hickup. then, like a jackass i thought "maybe i can make it even better". and for 2 days couldn't figure out why the engine was jumping and hesitating again.

the reason why was when i had reset the wheel, the engine was warm.
as a guy who is NOT a mechanic, just a garage enthusiast, i would venture that when setting that initial idle, it has to set the computer to understand what absolute zero is so it can make adjustments based on that.
when the engine was warm and i reset it, it was making calculations wrong.

like adding 2 plus 2 makes four, unless nobody tells you that one of the twos already had a 6 added to it before.... i hope that makes sense.

anyways. there's my saga. i let the engine cool overnight and did it again on sunday it runs fantastic! i'm doing 120 k (70mph) with no problems for as long as i need it to. (unless i encounter a grade of 6 degrees or better, ha.)

i'd appreciate your opinions and experiences and i hope that this helps as much as it did me.

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Vanagon Syndrome - Digijet??

I have an early 84 1.9 CA Westy, and noticed it had the harness "fix" installed at the AFM. The friend I bought it from had it installed by her VW mechanic when he was doing routine maintenance. From what I recall he told her she needed it, although I don't think it ever had the syndrome. In reading this forum I was to understand the fix only to be applicable to the Digifant. I removed the harness fix and noticed no change, but I don't drive it long or very often. Looking on the internet I found the original TB had been revised:


Technical Bulletin
Group: 24
Number: 92-01
Date: February 29, 1992
Subject: Vanagon Intermittent Misfire
Model(s): All Vanagon Digifant Fuel Injection Engines

Superceding, published a month later:

Technical Bulletin
Group: 24
Number: 92-02
Date: April 30, 1992
Subject: Vanagon Driveability Complaints
Model(s): All Water Cooled Engine Vanagons
SUPERCEDES TECHNICAL BULLETIN 24-92-01 (February 29, 1992)

The change was to the models - from "All Vanagon Digifant Fuel Injection Engines"
to "All Water Cooled Engine Vanagons. (the text was the same, bla bla install harness 025 906 302)

So my questions would be,

(My harness is 025 906 302 A).

should I put the harness back on, or just carry it with me in case the van starts acting up?

Has anyone here had the syndrome with the Digijet water boxer that was fixed with the added harness? Is it to resolve other issues?

Why are we banned from discussing vanagon syndrome here with the 1.9 digijet when VW TB 24-92-02 was revised to include all water cooled vanagons? Has it subsequently been ruled out?

I have to get a smog check done soon and want the van to be as close to factory spec as possible. It failed the pre-test and everything checked out except for a cracked injector tip sleeve or collar @ #1 & a leaky injector @ #3, so I'm replacing those.

Sorry if I'm repeating anything here I tried to search to see if this was covered but I couldn't find anything and it's not covered at all in the Bentley.

Thanks for any ideas or thoughts.



New member
vanagon syndrome?

After reading all these posts I think I have vanagon syndrome, only I have two symptoms that were not listed. The problems with my 87 westy seem to happen more often with a passenger in the rear seat on the left side, above the ECU and it happens even on short drives around town. I checked the ground for the wiring harness to see if the connection was clean and all was good. I detached the ECU from the underside seat and wiggled it to see if the harness connection was the culprit, but no stutter. I put the ECU back on and wiggled the whole seat and then I could get it to stutter. I shut off the car and then tried it again and it wouldn't do it. Could there possibly be some problem in the harness, or is it just coincidence and I should look into the air flow meter? Help!:confused:


New member
Vanagon Syndrome Air Flow Meter fix

Id try every one between the dizzy and the module, then to the engine. also recheck your grounds...maybe between module and fender.

Have you tried isolating your module from engine heat...maybe just a piece of cardboard from frame rail to hood and radiator shell to up against the master cylinder. Nothing pretty until you see if it works. It wouldnt be a fix, but a dodge, but if it works?? Later you could make something decent looking with some fresh air to it. an idea....trash it if ya wanna.