1988 Vanagon with bucking and eventual stalling problem

[srb]

Greetings,
I have an 1988 Vanagon 4-speed that just woke up to a major bucking problem.

The van was sitting for 3 months while I was out of town, then after I returned and drove it sparingly for a week, it started bucking during load, which was slight, but now has turned into undrivable bucking and stalling.

I did a bunch of searching on the site here, and have many ideas of how to begin my search and repair, but I wanted to take the opportunity to explain my van's scenario and see if I can elicit further insight.

Here is the program:

1. Van starts up solid, idles great.
2. I can drive off almost immediately, or let it "warm up" for 5 minutes, but after driving about half a block, it starts to buck (usually when I've gotten up to 2nd gear).
3. If I take my foot off the pedal and idle, all is good.
4. Start driving again, and the van will either drive good with small bucks here and there, or it will just buck and lurch like it's have a fit, and eventually, the van dies, and I have to coast of to the side.
5. When trying to restart the van, it cranks, but no turnover. I either have to let it sit for 5-10 minutes, or I can try and turn if over with my foot completely down on the gas, and eventually, it slowly turns over.
6. Sometimes, the RPM guage flies wild from 0 to 9000 or whatever, flipping back and forth. Sometimes, even the low oil alarm comes on.
7. When it finally turns over, it acts as if I just flooded the engine, which maybe I somehow did (even though it ain't a carb car).
8. I can then drive on, and half the time it continues to buck until I've given up and head back home, or it will run completely fine, as if nothing has happend. Frustrating tease.

So, I did an initial, visual inspection of the engine compartment, fuel lines and such, the air flow meter and the gas pedal connections, the grounds, etc. Everything looks decent and in proper place, and last year I cleaned and retightened all the grounds when I had to replace an alternator. I've also in the last year replaced the Type II sensor, and new spark plugs.

I read up on the weirdness of the ECU, and will try to see if removing it from the wall and laying it upside down fixes the problem, then remount it in that position. Or, consider a rebuild.

Also, the Hall Sender seems to often be a culprit in this type of bucking problem. I've never tested this part myself, but I'm wondering if replacing it—which I could easily do—would be just as easy.

Any advice before I begin the search would be greatly appreciated.

-Steve
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1988 Vanagon Wolfsburg

[srb]

UPDATE:

I opened up the back bench, took the ECU off the wall, and laid it flat down on it's back, still attached and inside the metal protective housing.

I drove the van around and had absolutely no bucking problems.

So, I'm wondering if I should just keep driving the van like that, with the ECU laid out horizontally instead of it's original vertical mounting, or I should just go get a replacement used ECU?

Also, could this be the wiring harness that is actually bad, and the ECU is functioning properly now because being laid down on it's back, I've either stretched out the harness or something?

Thank you in advance.
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1988 Vanagon Wolfsburg

[srb]

Just bumping this up, hoping for a response.

My van, after laying down the ECU, runs 95% normal now, the idle seeming low and I'm having problems during warming up with acceleration, but at least, no bucking or stalling.

I'm still wondering if the ECU or even the harness, should be what to replace.

Any help would be greatly appreciated.
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1988 Vanagon Wolfsburg

[Vanagon Nut]

I don't want to mislead you but two possibilities:

- ECU shroud is contacting ground (seat hinge)

- loose component on PCB of ECU

I've only read of these. No personal experience.

Can't see how first one could cause an issue, but the second has certainly happened to people. Heat, time, causes solder to fail at certain components. This could cause intermittent issues.

Neil.
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1981 Westy DIY 15º ABA
(VW Gas I4)

1988 Westy DIY 50º ABA

VE7TBN

[srb]

Help me out: what is the PCB?

I did unplug and replug the ECU before I laid it on it's back, under the bench. That also allowed me to stretch out the harness/wires.

It was an immediate improvement on the bucking/stalling.

So, my idea is to put back the ECU on the wall, and see if the problem re-occurs. I figure that is a good way to trouble shoot if the ECU has gotten worn/cracked in the mounted position, but in another, those cracks reseal, kinda.

Can an ECU also just get tired/worn out over time? My current ECU was put in this van by the PO, and on the ECU it has a sticker "2009 tested by Fidle to work 6/01/09." Could it have also just worn out?

Thanks for the reply, btw.
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1988 Vanagon Wolfsburg

[Steelhead]

ECU's can fail. My mechanic lends me a spare for long road trips.
You should consider yourself lucky that you are so close to solving this....Not sure how much research you've done on similar issues within the samba but we've seen some long shaggy dog stories as people chase bucking, etc.

Nice to be in striking distance.
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'77 Bay Window / '89 Caratsburg (aka. the Stormtrooper)

[MidwestDrifter]

PCB=Printed Circuit Board Its the actual core of the ECU where the wires from the harness connect to the electronic guts. There are solder connections that connect the plug on the outside to the PCB.
Over time constant heat cycling and vibration can cause the solder joints to crack. Only way to fix it permanently is to open the ecu up an re-solder. Usually its simpler to just get a good used ECU.

Here is an example of the cracking. The green board is the PCB.

_________________
2004 Dodge/Mercedes Sprinter (Custom Camper)
2000 Jetta TDI
1982 Diesel Westy W/ ABA I4 hybrid (Sold)
Epic Road Tripping since 08/05/12 | http://VagariesAbound.blogspot.com/
My Current Build | http://sprinter-source.com/forum/showthread.php?t=41215

[srb]

Thanks Midwest Drifter. I'd be game to crack it open and resolder, but yes, 100 bucks and I could just throw in a new, used ECU. Hmmm....
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1988 Vanagon Wolfsburg

[MidwestDrifter]

Ya if you can locate the bad joints its not to tough to fix. Sometimes you can't see the cracks, then its a hit or miss kinda thing. They way to prevent this it to stress relieve the plug where the harness connects to the ECU. The goal is to prevent any type of cyclical/fatigue stress by removing the possibility of vibration. It could also be your harness not the ECU. Might be worth it to follow the service manual checks for the harness, looking for an intermittent issue.
_________________
2004 Dodge/Mercedes Sprinter (Custom Camper)
2000 Jetta TDI
1982 Diesel Westy W/ ABA I4 hybrid (Sold)
Epic Road Tripping since 08/05/12 | http://VagariesAbound.blogspot.com/
My Current Build | http://sprinter-source.com/forum/showthread.php?t=41215

[Vanagon Nut]

[MidwestDrifter]

With most of the components on these boards, brief excursions to 200c is acceptable. In the factory they usually flow (melt the solder) in an oven.

They key to not damaging the components is to have your iron nice and hot and to get in and out quickly. A colder iron will take longer to melt the solder on the pad and can actually cause more heat damage.

For example xbox 360s have a common cold solder joint issue. I have fixed many by just tossing them in the oven...
http://www.se7ensins.com/forums/threads/xbox-360-oven-reflow-tutorial.201540/

Certain components don't like getting really hot, like capacitors. However they have small leads, so doing a hand re-flow isn't much of a concern.
_________________
2004 Dodge/Mercedes Sprinter (Custom Camper)
2000 Jetta TDI
1982 Diesel Westy W/ ABA I4 hybrid (Sold)
Epic Road Tripping since 08/05/12 | http://VagariesAbound.blogspot.com/
My Current Build | http://sprinter-source.com/forum/showthread.php?t=41215

[srb]

I wonder if one of you wizards could do me a favor:

Start of your van, lift the back bench up, and listen to the ECU. Does it make a high-paced clicking sound?

Mine does, it's rather loud, and I wanted to know if that is normal. Or, if any clicking sound should be heard from the device.

Cheers.
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1988 Vanagon Wolfsburg

[srb]

*bump*

Any one got the time to put their ear to their ECU?
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1988 Vanagon Wolfsburg

[MidwestDrifter]

I don't have a water boxer. But my digifant 2 ecu doesn't make any discernible noise. However my ignition module does make some humming noise sometimes. Maybe try out a used ECU?
_________________
2004 Dodge/Mercedes Sprinter (Custom Camper)
2000 Jetta TDI
1982 Diesel Westy W/ ABA I4 hybrid (Sold)
Epic Road Tripping since 08/05/12 | http://VagariesAbound.blogspot.com/
My Current Build | http://sprinter-source.com/forum/showthread.php?t=41215

[Ahwahnee]

My ECU seems silent... though on an 84 it is somewhat diffferent and in the engine compartment.

[srb]

I'm waiting to hear back from some ECU seller on thesamba.com.

I think I might as well break down and just buy a used on that's known working.
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1988 Vanagon Wolfsburg

[Flat in the back]

hi there, i came across your thread cuz i'm researching on how to fix my 89 vanagon.. it had the similar bucking situation for the past few days. the engine bucked when i took off in every gear, it even backfired at one point. but if i were to give it a few revs or keep the rpm high then i was able to take off fine. i was figuring it out in my head as i was driving, thinking it might be either fuel or hall sensor. but this morning after i pulled out of the walgreen's driveway, the van just stalled as i was shifting. i didn't even notice it at first, but then i thought i might be low on gas. so i put some fuel in it and checked the 7mm bolt at the fuel line T and there was gas squirting out. so i replaced the distributor with a good used one i bought a while back as a spare, and it didn't make any difference.. my van still isn't starting
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2005 Saab 92x Aero: Flat in the front (for sale)
1970 Porsche 914-6: Flat in the middle
1958 Volkswagen Panel Bus: Flat in the back
1989 Volkswagen Vanagon Bluestar: Flat in the back

[morymob]

U may notice that the cable to the ecu is pretty stiff with time and caused mine to pop partially off once. Take a heat lamp/heat gun and carefully warm up cable until it bends easily(after ecu mounted) and re-bend so no strain on connector. Have u done ALL the grounds recently?

[Flat in the back]

[crazyvwvanman]

"Vanagon Syndrome" has nothing to do with any starting problems. Most vans with the true syndrome start fine. That is one of the ways the syndrome is officially diagnosed. The van starts fine, drives fine, but after a while it start bucking or whatever. If you stop and start the engine the bucking always goes away. It may come back soon or it may not come back for a long time. That is the syndrome symptoms. Of course you can have more than one problem, including the syndrome.

Mark