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Sat Jan 31, 2015 10:23 pm

I have a 1984 1.9L Vanagon that has been giving me hell. It has a intermittent problem of loosing power which seems to only happen when the van is at operating temp. At times the fastest I can go is 45 mph. If I step on the gas to try and increase speed the van will loose more power and eventually stall out. If I pull over and let the van cool off for 15-20min it will act like nothing was ever wrong. Vanagon syndrome on a 1984???

Here is a list of what I have done to the van recently.
New fuel lines, Fuel tank re-seal kit (due to leaky gas tank), New fuel filter, New distributor cap and rotor, New spark plugs, New plug wires, New air filter, All new vacuum lines, Cleaned engine grounds, New oxygen sensor, New temp 2 sensor, Swapped in spare used air flow meter, Swapped in spare used ECU, Installed new manifold gasket, New manifold hoses, Swapped in spare used distributor (due to funky looking wiring), Swapped in spare used ignition control unit (Hall), Swapped in spare used idle stabilizing unit, Tested coil with ohm meter from specs in Bentley (pass), checked catalytic converter for broken pieces by tapping it with a rubber hammer, and tested the battery (pass) at 12.78 volts.

Had my mechanic pressure test my fuel lines (pass), test fuel pump relay (pass), Adjust throttle switch, Check timing, Check wiring harness and recheck grounds (pass), and Bleed the cooling system.

At this point I am thinking it is electrical because of the problems intermittent nature, and the coil in my mind is the main suspect (over heating). It passed the test with the ohm meter but that doesn't give me total confidence.

Throw more money at the van and buy a new coil?

I am running out of things to check!!!

HELP ME OBI WAN KENOBI YOU'RE MY ONLY HOPE! :cry:

Sat Jan 31, 2015 10:54 pm

Good question. You may get more help if you add specifics (power loss, etc) to the subject rather than "help me"

It's very benificial when someone else has the same problem in the future & they do a subjet line search.

Anyway - try unplugging the O2 sensor

Sun Feb 01, 2015 1:10 am

Just off the top of my head, are the used spare units (AFM,ECU,Hall ignition unit) all known to be good? Won't cost anything to try a swap back to original.

Sun Feb 01, 2015 5:48 am

I also have an 84 that had a very similar issue when I first first got it. The shop I purchased it from was nice enough to let me take it on a couple trips and then bring it back in and report any problems. They replaced the AFM at no charge, which fixed it for me.

There is a contact strip inside the AFM that wears out over time. I think this is what was causing my issue. Not sure why it presented like vanagon syndrome or whatever its called though. Maybe heating up the engine causes some minor movement inside the AFM.

Sun Feb 01, 2015 9:35 am

wesitarz wrote: Just off the top of my head, are the used spare units (AFM,ECU,Hall ignition unit) all known to be good? Won't cost anything to try a swap back to original.

All the parts I swapped in are spare parts I got from my Uncle which as far as I know are in good condition. I only installed them after the problem started to see if there was any change in condition.

Sun Feb 01, 2015 9:41 am

jfu057 wrote: I also have an 84 that had a very similar issue when I first first got it. The shop I purchased it from was nice enough to let me take it on a couple trips and then bring it back in and report any problems. They replaced the AFM at no charge, which fixed it for me.

There is a contact strip inside the AFM that wears out over time. I think this is what was causing my issue. Not sure why it presented like vanagon syndrome or whatever its called though. Maybe heating up the engine causes some minor movement inside the AFM.

Did they shop rebuild your old AFM some how are was it a brand new unit?
I did swap out the AFM with a spare that I had after the problem started just to see if the power loss remained. No luck. I guess it is possible that both meters are bad?

Sun Feb 01, 2015 9:50 am

you did good, all the intelligent stuff to do was done.

It sound and feel like a surge. Some kind of flooding. To much fuel.

Like someone said start by unplugging the OS (even new...), ECU will go in safe mode.

Sometime fuel pressure look fine at idle or 2000 rpm but it's not at highway speed. Any sign of fuel in oil?

The temp sender, the blue one, was the old one doing the same thing?

Ben

Sun Feb 01, 2015 9:52 am

Make sure the wiring harness connector to the ECU is connected all the way. It can be difficult to properly seat after you have removed it. Take off the left taillight and look at it head on.

Sun Feb 01, 2015 9:55 am

[Anyway - try unplugging the O2 sensor[/quote]

I did try driving with the O2 sensor unplugged once before with no change but it's worth another shot. I did replace the old sensor with a new one.

Sun Feb 01, 2015 9:58 am

Coils can fail when they get hot and then work just fine again as they cool off. Checking the resistance of the coil is not a definitive test as to whether the coil is good or not.

Sun Feb 01, 2015 10:00 am

kg0483 wrote: [Anyway - try unplugging the O2 sensor

I did try driving with the O2 sensor unplugged once before with no change but it's worth another shot. I did replace the old sensor with a new one.[/quote]

well, take a voltmeter and sadly start checking for continuity between ECU and connector/sender.

begin with the injector.

Ben

Sun Feb 01, 2015 10:03 am

ftp2leta wrote: you did good, all the intelligent stuff to do was done.

It sound and feel like a surge. Some kind of flooding. To much fuel.

Like someone said start by unplugging the OS (even new...), ECU will go in safe mode.

Sometime fuel pressure look fine at idle or 2000 rpm but it's not at highway speed. Any sign of fuel in oil?

The temp sender, the blue one, was the old one doing the same thing?

Ben

I will try unplugging the O2 sensor again.

How can I check if there is fuel in the oil? I just did an oil change not that long ago. Would that effect the test?

The temp sender was fine as far as I know but I just replaced it to rule it out as a possible issue.

Sun Feb 01, 2015 10:08 am

Wildthings wrote: Coils can fail when they get hot and then work just fine again as they cool off. Checking the resistance of the coil is not a definitive test as to whether the coil is good or not.

That was my thought too. Maybe I should bight the bullet and just get a replacement. Unless there is some other way to test it?

Sun Feb 01, 2015 10:33 am

Perhaps test the wiring for the Temp sensor? A new sensor means nothing with corroded wires or broken connector.

Sun Feb 01, 2015 1:53 pm

Just got back from a test drive. I unplugged the O2 sensor and drove the van till it was up to operating temp and sure enough it started to loose power again. I pulled over and let the van cool for 15min. It started right up and I drove fine for 8-10 min, then I could notice a slight hiccup but the bus was still charging up long steep hills at 40-45 mph no problem.

Sun Feb 01, 2015 1:55 pm

geo_tonz wrote: Perhaps test the wiring for the Temp sensor? A new sensor means nothing with corroded wires or broken connector.

I checked the wires and connections to the temp II sensor. Seems to be in good shape.

Sun Feb 01, 2015 2:05 pm

I'm wondering if the timing could be wrong? I've noticed the vanagon has kinda a rough idle now when it's cold. My mechanic says it's timed correctly but who knows. Maybe I'll bust out the timing light again. :roll:
It is my understanding that incorrect timing would cause power loss and other issues consistently (hot or cold), not just when the van was at operating temp. Is that correct?

Sun Feb 01, 2015 2:07 pm

Try cleaning the AFM wiper. Radio shack sells a really good cleaner for rheostats & potentiometers

Sun Feb 01, 2015 2:48 pm

If your year model came with a dual vacuum/dual advance distributor and the retard can is bad (very likely) or the original dizzy has been replaced with a single vacuum/dual advance unit, you can not time your engine according to the specs in the book. It is best to always time it at full mechanical advance, which if I remember for a 1.9 is something like 30° BTDC at 3500+ rpms, hoses off.

Sun Feb 01, 2015 4:18 pm

Just got back from another road test. I had found a used coil in the goody basket of used parts my uncle give me so I decided to toss it in the van and give it a whirl... same problem. :(