TheSamba.com :: View topic - Need some help with possible Vanagon Intermittent Syndrome

Sun Oct 19, 2014 7:03 am

Not sure if what I have going on is the known intermittent syndrome or something else so figured I'd see if anyone could shed some light. I just bought an 1987 Vanagon Westy and the previous owner let me know before hand that it had symptoms similar to VIS. He would be driving along lose power restart and be good to go... it seems like it has gotten worse though as now its hard to go a mile or two without needed a restart. I've compiled a list based on the records I received with the van of what has been replaced, checked, etc.. I tried to keep the list to things related to VIS but some other things may be in there as I'm not a great mechanic by any means! Any insight would be greatly appreciated.

Also the AFM was replaced with used unit and I will be able to try a friends working AFM in next few days.

Sorted by most recent
2014

-Installed Volt regulating Diode ito wiring for temp sensor
-R&R Fuel Pump

2013 (approx mileage 154k)

-Tracing and testing wiring harness
-Replaced ECM Unit
-Installed Signal Filter between Mass Air Flow Sensor and main wiring harness
-Added ground from distributor to engine block
-R&R Mass Air Flow Sensor (with used one so this could still be issue)
-R&R Thermostat
-R&R Water temp sensor
-R&R ECM Unit
-R&R Starter and Bushing
-R&R Instrument Cluster and Changed out Voltage Reducer (used part) Traced our wiring and grounds
-Cooling System flushed
-Set Idel and R&R Both Coolant Temp Sensors
-R&R Aux Fan Switch and Fan Resistor Control

2011 (approx mileage 153k)

-R&R Spark Plugs, Distributor Cap, and rotor button
-New O2 sensor

2008 (151k mileage) (looking at records it looks like the syndrome started about here)

-R&R Water pump and temp sensor
-New Belts

2000 (103k miles)

-R&R Cylinder heads, fill corroded surface on cycle head, resurface, new head gasket

Tue Oct 21, 2014 7:09 am

The van also has an erratic idle which when I bypass the Idle Control Unit (small black box behind rear tail light) gets better but not perfect...
planning on cleaning out the idle valve

Also yesterday tested the AFM with ohm meter but there isn't very much info out there as to what is normal.. mine changed through arc for about half of arc then went back towards starting point through finish of arc.

Tue Oct 21, 2014 8:40 am

A good AFM should show a smooth change in reading through the entire arc. It is best to do this with an analog needle tester so that you can watch the motion of the needle. If you are sure you did not lose contact with the leads while you where testing it, then you have part or all of your problem right there.

Good Luck!

Hans

Tue Oct 21, 2014 10:19 pm

I once had an intermittent cutout that over time turned into a stall. When it stalled I felt compelled to solve the problem. The culprit was high resistance in cable from coil to distributor. That cable in Bosch version houses a 1k Ohm resistor and over time it turned out to about 8k Ohms just enough to cause trouble on longer drives.

Wed Oct 22, 2014 6:32 am

Updated.

Put in a known working AFM which did not change anything.
Tried running with no o2 plugged in and no change.

When we start the van it will idle ok for a minute then start searching for idle then stall out (this has been without driving the car just starting it).

Going to test o2 sensor today as this seems to be common culprit to running problems and seemingly easy to troubleshoot.

Thanks for input thus far.

Wed Oct 22, 2014 7:51 am

Not the O2 sensor. It needs to be up to temp before it does anything and won't get there in a minute.
Look at the idle control valve. try blasting some carb cleaner through it to clean it out, or try swaping it out with a known good one (from a friend). Mine needed replacing and solved a similar problem.

Sat Oct 25, 2014 5:58 am

o2 sensor was wrong sensor and only had one plug of 3 so changed that, but there is a huge exhaust leak before the sensor so thats running super rich when plugged in.

Idle still tends to surge or search once van warms up. Took it for a spin yesterday and after a few minutes lost power.. turned off and back on and drove back to shop with no problems.

Will get that exhaust leak fixed as that could obviously be part of some problems but would it be causing the "syndrome" of losing power?

thanks
eric

Sat Oct 25, 2014 4:34 pm

It must be that time if year or something... My '87 WBX started doing the same exact thing 5 days prior to you posting. Started hesitating when I gave it gas and within a hundred feet I had no response at the pedal. Coasted off to the side and turned it off, after checking oil and restarting it got me back home no problems. Changed the plugs, rotor, distributor, oil and filter today hoping it was the fouled plugs/distributor but no luck. Took it for a drive and as soon as I got going it lost power. At one point I had no response at all from pedal, had to listen to make sure van was still running(it was), the OXS and Battery indicators lit up for a few seconds. After sitting for dinner it seems it's running better... 'ish.

Mon Oct 27, 2014 2:03 pm

Did a compression check today, readings are within acceptable limits from Bentley manual. The "front" cylinders looking at engine are at 140 left and right, the "rear" are at 120 left and right. Manual states compression pressures are 85-135 psi with a difference differential of 42 psi. Not sure if the 140 was me cranking it too many times or if it's actually over limit, or for that matter if it is normal... A mechanic I am not. While cranking, I noticed a puff of light smoke from the area of the left exhaust pipe. Looking closer the pipe is pitted and worn and it looks like the gasket it just... Not there.

Is that the same location you noticed your leak before the O2 sensor?

Would this cause the rough running (almost stalling now) and power loss?

-Rick

Wed Oct 29, 2014 8:51 am

When I had "suspected Vanagon syndrome" it turned out to be an intermittently bad coil. After testing and/or replacing just about every other potential culprit, I noticed the tach needle starting to twitch just before the start of another "episode". Since an engine can't change RPM that quickly and the tach gets its signal from the coil, the smoking gun was identified. Replaced the coil, car runs perfectly since.

Wed Oct 29, 2014 9:28 am

dspieg wrote: When I had "suspected Vanagon syndrome" it turned out to be an intermittently bad coil. After testing and/or replacing just about every other potential culprit, I noticed the tach needle starting to twitch just before the start of another "episode". Since an engine can't change RPM that quickly and the tach gets its signal from the coil, the smoking gun was identified. Replaced the coil, car runs perfectly since.

Is there a specific name for the coil? Trying to find it in the Bentley.

Wed Oct 29, 2014 9:42 am

Rekker wrote: dspieg wrote: When I had "suspected Vanagon syndrome" it turned out to be an intermittently bad coil. After testing and/or replacing just about every other potential culprit, I noticed the tach needle starting to twitch just before the start of another "episode". Since an engine can't change RPM that quickly and the tach gets its signal from the coil, the smoking gun was identified. Replaced the coil, car runs perfectly since.

Is there a specific name for the coil? Trying to find it in the Bentley.
Ignition coil
http://www.van-cafe.com/home/van/page_685_236/coil-bosch-fits-1985-through-1991.html

Wed Oct 29, 2014 9:44 am

Perales wrote: Rekker wrote: dspieg wrote: When I had "suspected Vanagon syndrome" it turned out to be an intermittently bad coil. After testing and/or replacing just about every other potential culprit, I noticed the tach needle starting to twitch just before the start of another "episode". Since an engine can't change RPM that quickly and the tach gets its signal from the coil, the smoking gun was identified. Replaced the coil, car runs perfectly since.

Is there a specific name for the coil? Trying to find it in the Bentley.
Ignition coil
http://www.van-cafe.com/home/van/page_685_236/coil-bosch-fits-1985-through-1991.html

Thank you! I actually just found it in the Bentley when your post came through. :D

Wed Oct 29, 2014 9:56 am

dspieg wrote: When I had "suspected Vanagon syndrome" it turned out to be an intermittently bad coil. After testing and/or replacing just about every other potential culprit, I noticed the tach needle starting to twitch just before the start of another "episode". Since an engine can't change RPM that quickly and the tach gets its signal from the coil, the smoking gun was identified. Replaced the coil, car runs perfectly since. lol like this :arrow:

Thu Oct 30, 2014 3:08 pm

I guess I'm going to have to get a voltmeter and try going through every electrical test I can find in the Bentley.

I pulled the ignition coil, which looked no where near as bad as the photo you provided lol. I went to the auto parts store thinking it had corrosion crystals in the distributor cable plug, turns out to be what appears like some kind of conductive grease I think. Advance auto wanted $75 for a coil (not even a Bosch), so I'll prolly order from vancafe ($50'ish for Bosch) after trying electric system tests.

Pulled the fuel filter and still looks good. I drained it and air passes through it both directions easily so I don't think it's clogged. I can hear the fuel pump kicking on when I turn key on and the line was under pressure when I checked the filter.

The exhaust is coming out with good pressure, no rattles when I tap at Cat...

I did try disconnecting the O2 sensor, and letting it idle. It ran the same as with it plugged in. Still hesitates when I give it gas and idles rough. Would that indicate it was faulty with no change?

I did notice after taking off the coil and fuel filter and putting them back on that now the led on the tach for the temp gauge goes off after starting the van, then starts flashing again and won't go out.

I love driving this van... But oh my god it's a fickle beast! :D

Thu Oct 30, 2014 3:22 pm

Download these VW protraining manuals. They are a good addition to the Bentley and can be a great help to debug problems.
http://www.westfalia.gomezperales.com/Documents/86%20Vanagon%20Protraining.pdf
http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%2086-91%20Fuel%20Systems.pdf
http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%20Digifant%20I%2086-91.pdf

Thu Oct 30, 2014 3:59 pm

to sort out the running issues in my 86 vanagon, I got the Van café injection tester, rented it them bought one. good tool for injection issues, I found several faults to repair, some would have been difficult to diagnose otherwise.

Not only did I have injection issues, but also one final issue was faulty distributor, the hall sensor was intermittent, every now and then it got funky, it was very intermittent, hard to find.

now no issues at all.

the van café tester is well worth the money in saved hours of you try to trace injection faults, you leave it on as you drive so you can catch intermittent faults as they happen, and see what is causing it. It will tell you if the O2 sensor is going bad, if voltages are low, what the temp sensors and air sensors are doing, etc..

good luck

Thu Oct 30, 2014 4:45 pm

Perales wrote: Download these VW protraining manuals. They are a good addition to the Bentley and can be a great help to debug problems.
http://www.westfalia.gomezperales.com/Documents/86%20Vanagon%20Protraining.pdf
http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%2086-91%20Fuel%20Systems.pdf
http://www.westfalia.gomezperales.com/Documents/Vanagon%20Protraining%20Digifant%20I%2086-91.pdf

I'm reading them now, thanks for another source of info on the van!

Thu Oct 30, 2014 5:23 pm

Rekker wrote:

I did notice after taking off the coil and fuel filter and putting them back on that now the led on the tach for the temp gauge goes off after starting the van, then starts flashing again and won't go out. you have unplugged the sensor on top of the coolant reservoir I bet...this is a long shot but make sure the harness to the alternator isn't holding on by a thread... I think this happened to me once if I'm not mistaken...

Thu Oct 30, 2014 7:34 pm

Bluebus865: What's this "injection tester" at Van Cafe. I searched their site and couldn't find it. Thanks for the help.