Vanagon Intermittent Syndrome - HELP! (Warning: long read)

[shaun86westfalia]

Hello, fellow Vanagon addicts! (sufferers?)

We are long time forum lurkers/loiterers, but first time posters. Please bear with me, as I try to give as much information as I can, which has led to my wife and I at the end of our ropes.

Our van is a 1986 Vanagon Westfailia with the 2.1 litre Digifant engine, and we are located in Calgary, Alberta, Canada. We bought the van back in 2018, and it ran very well for us up until the beginning of this summer.

Current odometer: 238,875

Where did it all go wrong, you might ask?

At the beginning of June we had a heat spell, and the van quit for the first time at the top of a pretty steep hill just outside of Calgary. I had been driving it in 30+ degree Celsius weather for about 45 minutes or so, when part way up the hill, the tachometer started bouncing around, and felt to me like it wouldn't shift, so naturally I let off the accelerator pedal, and POOF the engine just quit, so I pulled over to the shoulder. I thought that it was related to the heat, so I unpacked the back cargo area, opened the engine lid, and waited for 10-15 minutes. I was then able to restart the van by giving it some revs. It quit again at the top of the next hill because again, I had let off the accelerator. And then it quit a third time as I got off on the exit I needed, after a couple of less severe hills.

Over the course of the summer, we drove the van around the city in short stints, and it didn't quit at all. We thought for sure the issue was related to something with the heat and/or extended periods of driving.

We then proceeded to have our mechanic change out the following (all new parts) in 3 successive trips to the shop, when the prior part didn't help:

( 1 ) Ignition coil
( 2 ) Hall sender/sensor/generator
( 3 ) Fuel pump
( 4 ) Alternator (this was changed not as a result of the quitting issue, but because the bearing was going, and causing extreme shakes in the engine bay)

After the fuel pump was installed, we thought we had hit the jackpot. We did 4 hours one way in very similar heat, and then 4 hours back in similar heat, around 800 kilometres round trip. No issues at all.

Queue up a big road trip we had here in September. On the first day we had done several hundred kilometres with no issue. On day two, however, the tach was bouncing a little bit, but we didn't pay a lot of attention because we were following a semi-truck and it was quite windy. Then we got near the top of a big hill a bit later, the tach goes nuts, with the engine following suit -- either extreme revs, or almost complete loss of power. Letting off the accelerator at the top of the hill resulted in the van quitting dead near Kelowna.

We decided not to let it cool off this time, and instead start it up again, and found that it would start immediately AS LONG AS we also pushed the accelerator.

Now we're thinking maybe something in the EVAP system is clogged, or maybe even the ECU itself needs a reset... (we are just guessing at this point)

We get out to Vancouver and stop in to see some of the Westy specialist guys out there, but they could only give us a little time as drop-ins. They change out the following parts:

( 5 ) 2x Relays in the left side of the engine compartment for the fuel pump and power supply
( 6 ) Signal filter (GoWesty brand) for the airflow meter (AFM)
( 7 ) Idle control stabilizer unit (ICSU) (unrelated to the problem, but ours was dead for years with the 2-pin connector on the top of the engine disconnected)

Those guys started to hint at something electrical, if the problem persisted, but also thought that the EVAP system sounded resonable.

While we were out on Vancouver island the issue seemed to be getting worse, but as long as we stayed steady holding down the accelerator, or really punching it down, we could seemingly work through the issue and at least keep rolling.

Queue up a number of rainstorms, and now we're trying to get off of the Sunshine Coast back onto the mainland just north of Vancouver. In the rain on the way to the ferry, the van keeps quitting. We get onto the mainland, heading up towards Whister through Squamish, and the tach is just going nuts, and the extreme revving or losing power seems to be getting worse the wetter we get.

We call our mechanic, and he recommends:

( 8 ) disconnecting the oxygen/lamda sensor

We get up to Whistler from Squamish with not a single hesitation, so we naturally think THIS IS IT. Just a silly $20 USD oxygen sensor ($80 USD if we were to pay up for the GoWesty one with the new harness). This is FANTASTIC.

NOPE.

We go to leave Whistler, still wet conditions, hesitating like crazy even on the downhill. But not even right away: not until we were through Squamish and almost back into Vancouver, about an hour of driving before it acts up. False sense of security SMASHED, confidence level back down to ZERO. But hey, we've made it this far, we'll at least get home (about another 1000 kilometres to go after 3500 already).

We limp back to Calgary, and decide it is time to get a Bentley manual, Haynes manual, read How To Keep Your Volkswagen Alive cover-to-cover, roll up the sleeves, and become a partially self-sufficient Westy owner (FINALLY).

Going through the lists of things to try with Vanagon Intermittent Syndrome (besides #1, #2, #3 already mentioned), we start with all the small tune-up procedures, and perform the following:

( 9 ) Oil change with LiquiMoly 5W-50 (unrelated, but needed to be done after the long trip)
( 10 ) New distributor cap (Bosch)
( 11 ) New rotor (Bosch)
( 12 ) New ignition wires (Bremi)
( 13 ) New spark plugs (NGK BP6ET tri-tip)
( 14 ) Idle adjusted to right around 900rpms (we adjusted the screw at one point on the trip to allow more airflow to try and get it to run better, so we now dialed it back)

EDIT: Adding these next two tests since original post:

We borrow the following known-to-be-good parts from our mechanic:

( 15 ) Airflow meter mounted on air cleaner
( 16 ) ECU (same part number and revision number)

*Latest/current conditions* for quitting:

At this point, if the van has sat for long enough to cool completely (6-8 hours seems to do it), the quitting issue can be recreated quite easily. The van turns over great straight away. We let it idle for 2-3 minutes, it'll start idling roughly, and then quits dead in the driveway. To get it to start again, we can turn it over right away, but only by pushing the accelerator quite a bit. If we then let it idle on its own, it'll quit again almost right away. We can repeat this quitting event 2-3 times before the van is seemingly too warm to quit.

The other set of conditions under which it seems to quit are after it has been up closer to highways speeds (say 80-100km/hr) for a few minutes. It will often do the tach jumping show and dance, and then when we come to the next stop, it'll quit dead and require being turned over with accelerator being pushed.

Note: when the tachometer jumps around, the engine always is in-line with the RPMs, either revving hard, or lurching.

We get some fancy equipment to do some of our own testing, and perform the following:

( 17 ) Timing is perfectly set at 3000 rpm for 35 degrees advance

( 18 ) Compression test (cold, not warmed up, and "dry"): #1 = 130psi; #2 = 130psi; #3 = 105psi; #4 = 130psi

( 19 ) Fuel pressure test - 35psi holds steady right through the van quitting while sitting and idling, tapped in at the fuel feed T-junction

This tells us nothing really, but at least we got confirmation that probably the fuel pressure regulator is working okay.

And finally we arrive at today, where we find a copy of the Digifant Pro Training manual that has been so kindly updated by Kamz:
https://www.thesamba.com/vw/forum/viewtopic.php?t=725680

( 20 ) We run through all electrical tests on pages 40 & 41

Here are the results that appeared to be abnormal in some way:

Test fuel injectors and wiring for total resistance
12 at ECU and 87 at Fuel Pump Relay
Specifications: 3 to 5 ohms
Our result: 8.5 ohms (too much resistance? could this BE RELATED?)

Test throttle switch in closed position
6 and 11 at ECU
Specifications: 0 ohms
Our result: 0.8 ohms (low enough?)

Test fuel pump wiring
At components, wiring between fuel pump relay/ground and 2-pin connector
Specifications: Continuity on both wires, individually
Our result: Right wire (when looking down at connector from rear of vehicle) has continuity; Left wire, no reading at all on multimeter

( 21 ) Additionally, we ran the fuel injection relay checks from 24.32 of the Bentley)

With the ignition on, adapter B (on the left, Power Supply Relay) is supposed to get voltage approximate to the battery voltage on terminal 85 (on the right), but we get nothing on 85, and instead get the battery voltage on 86. Unsure if this matters, as both 85 & 86 appear to open when the relay is switched.

So...that's a very long-winded way of stating we are puzzled (to say the least).

Our plea is for any Vanagon Sherlock Holmes' out there to put on their double-brimmed hats, grab their magnifying glasses, and PLEASE (pretty please?) provide as much free advice as your heart can allow.

Thanks in advance!
Shaun (and Miranda)

[davlance01]

Sounds like a really really really long way of saying you have a miss in one or more of your cylinders. Watch some "what is a misfire?" Videos.

Here's what you do before you spend a dime on anything else.

Get yourself a temperature gun from harbor freight, amazon.com or wherever you get cheap tools.

Like this one...
https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html

Start the car and as it warms up hit the laser and grab the Temps on each cylinder by pointing at the exhaust as close to the head as you can get it. Now IF there is no significant differences in the Temps then take the car for a drive to get the exhaust good and hot and then check again.

Take note of the temperature of each cylinder, the ones that are cold are your dead cylinders. In other words a cylinder that isn't firing isn't creating exhaust either resulting in a colder or cold exhaust at the problem cylinder.

After you identify the problem cylinders turn to the page in your Bently or pro training pdf and test your injectors at the cold cylinders before you do anything else. My digijet manual states 87cc (87 ml) in 30 seconds I imagine the digifont is the same but double check.

And never forget that money spent on diagnostic tools is better spent than money spent on fancy socket sets.

My money is on a clogged injector or 2. Please don't just pull the trigger on the parts cannon before being 100% sure the part your buying is fixing the issue.
_________________
Life is short and the road is long so if you want to see it all you have to drive fast!

[shaun86westfalia]

Thank you very much for the sound advice, we really appreciate it. We’ve ordered a temperature gun, and will be able to run the test you recommended as soon as it arrives (Monday).

Quick follow-up:
Should we be concerned about the 8.5 ohms resistance rating on the ECU pin 12 to fuel pump relay pin 87? Or is that a trial ballon to let float away?

[davlance01]

Being that you are asking the question about the ohms in the wire I'm going to guess you do not know how to do a voltage drop test.

Watch this....
https://youtu.be/DfLyh43iihM

You own a old vw you got to know how to do a voltage drop test or you'll be driving yourself nuts

If I had a nickel for every wire end I had to replace I could buy me another van

Yes you should look closer at that high resistance wire, should you be concerned? Being concerned is reserved for people who do not know how to diagnose their own cars.
_________________
Life is short and the road is long so if you want to see it all you have to drive fast!

[djkeev]

On the 86 the tachometer is fed by a green wire that plugs onto the ignition coil.

Unplug it.

You won’t have any tach signal but the chances are good that you won’t stall out any more.

If this isn’t the problem? Well it was a cheap try!

Edit: even if you don't have a tach, it is prewired for one, unplug it anyway.

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[davlance01]

[Howesight]

I have some thoughts on this conundrum:

1. The first thing that comes to mind for me is the symptom of the "bouncing tachometer." There are really only two possible causes for this tell-tale symptom. The first, which the OP already addressed, is a faulty Hall sender or related wiring. The second is a failure in the ECU printed-circuit board. These failures happen a lot more often than one would think. There is a "field repair" available and a more permanent repair - - replacing the ECU. For the "field repair", disconnect the battery, then the ECU connector, removed the ECU and turn it around 180 degrees and re-install. The object is to have the ECU harness pull on the Printed Circuit Board that it attaches to in the opposite direction. The harness directly attaches to the PCB (it should have been made with some kind of strain support) and can cause it to lose electrical contact where the thin copper traces extend over cracked parts of the PCB. Heat plays a role in causing expansion that opens the cracks. The ECU replacement you used may have this exact problem.

2. Another possibility is that the oxygen sensor coaxial cable is shorting from the inner signal wire to the out ground wire. This can happen in a fashion that is intermittent, although most Vanagons that develop this problem do not experience it in an intermittent fashion. Also, this would NOT cause the tach needle to bounce around. Here is a link addressing the oxygen sensor cable issue: https://www.thesamba.com/vw/forum/viewtopic.php?p=7283386

There are a number of important grounds in the engine compartment, at least one of which is likely contributing to the slightly high resistance noted at the fuel injectors. Ground fails can act intermittently. The terminal ends allow moisture to attack the copper strands under the wire insulation and that affected oxidized wire can be as much as 1/2" to 1". Where this is found, you must cut off the terminal, cut out the compromised wire and install a properly-crimped replacement terminal. This process also lets you eliminate a lot of other potential sources of the running issues.
_________________
'86 Syncro Westy SVX

[davlance01]

So you want the guy to flip his ecu around, replace oxygen sensor wire and clip the ends of his ground wires back 1 inch?

1.5 hour free voltage drop course will take less time.
https://youtu.be/YaYtCVBodpw

And accomplish more.
_________________
Life is short and the road is long so if you want to see it all you have to drive fast!

[DigiMatrix]

[djkeev]

Probably NOT your problem but worth looking at are the two connectors on the Power Steering speed boost Valve at the pump fitting.
These connectors are alive and infused when the key is on.
On most older units the terminal insulators are long gone by now.

Anyway if/when they come undone and short out, they can fry the interior wires of the fuel injection harness.
Symptoms are usually more severe but who knows?

Worth looking into anyway.

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[shaun86westfalia]

Thanks to everyone for their responses. I found a bit of time to try out some of the suggestions.

[DigiMatrix]

[davlance01]