Vanagon Syndrome like condition on Air Cooled?

Yellow Van

81 Vanagon air cooled motor

Bucks hard or looses a lot of power after the van has been driven for about 15-20 minutes. Runs very well before that. This happens if the 02 sensor is connected or not. Stopping for a few minutes will resolve the problem temporarily.

This only started after I replaced the fuel lines, a bad injector, and intake manifold gaskets. I'm guessing some wiring was damaged and is causing an electrical problem that confuses the computer similar to what happens in "Vanagon Syndrome".

Does the "capacitor fix" (http://www.geocities.com/harald_nancy/intermitt._syndrome.htm) work on the air cooled AFM?

What should I check?

Randy in Maine · Posted: Mon Apr 13, 2009 11:27 am Post subject:

Just invest in a new Temp Senosr II for $20.

http://www.busdepot.com/details.jsp?partnumber=0280130012

GBA 88West LA · Posted: Mon Apr 13, 2009 11:28 am Post subject:

i believe theres a special harness that you attach to the AFM unit,located on top air filter housing i know theres been much discussion here in regards to it....if the search function doesnt yield the answers hopefully someone will chime in
_________________
88 Westy GL Vanaru 07 2.5 EJ25/AA Trans/oiling plates, 1.14 3rd-.77-4th..solar powered cabin

Yellow Van · Posted: Mon Apr 13, 2009 11:29 am Post subject:

I already have a new Temp II sensor.

RCB · Posted: Mon Apr 13, 2009 11:30 am Post subject:

Yellow Van Is it possible you buggered up the temp sensor?? Its real close to those manifold gaskets you just changed.
A loose wire or broken wire is easy to miss.
That little part if not working will create havoc to your engine.

Imagine your engine bucking like Linda Blair in the Exorcist.

I think Ive created a new phrase for the air-cooled Vanagon Syndrome which is usually associated with water cooled Vanagons.

"The Linda Blair Syndrome" Evil or Very Mad

RCB · Posted: Mon Apr 13, 2009 11:32 am Post subject:

Whoops....youz guyz typed faster than me did.
New or not I think this is a temp sensor thing.

Temp sensors at Arizona Autohaus are $11.00 each

Randy in Maine · Posted: Mon Apr 13, 2009 11:32 am Post subject:

I like to measure it at the big plug that plugs into the ECU myself

Do you have an O2 sensor on this thing?

Have you checked out the throttle positioning switch?

Yellow Van · Posted: Mon Apr 13, 2009 11:44 am Post subject:

The 02 sensor is new and does put out voltage in roughly the right range. I haven't tested the temp 2 sensor since the "vanagon syndrome" like problem started.

The story of the temp 2 sensor is a bit of a nightmare. Last year I noticed the resistance from the temp 2 sensor was wrong and tried to replace it. Unfortunately the sensor snapped off inside the head!

Several hours of several people trying to tap a new hole were largely unsuccessful. I had no room to get a drill in there.

Finally a friend managed to got a few threads in so the new sensor makes solid contact with the head but is mostly sticking out of the hole it should be in. I know this should cause a delay in response but it didn't seem to cause trouble before.

Yellow Van · Posted: Mon Apr 13, 2009 11:49 am Post subject:

reluctantartist · Posted: Mon Apr 13, 2009 12:57 pm Post subject:

I think you have a vacuum leak issue...it is easy to get one when you are working in the engine with old rubber parts. Look at the intake elbow closely sometimes it has a crack that doesn't really open until it is warm. The auxillary air elbow often fails. The rubber Y going to the brake booster and decel valve. Check the decel valve for proper functioning. If any of the vacuum hoses are original then you have a high probability you cracked one when moving things around. Is your temp II still in place? If you haven't bumped it and everything worked before then it may still be ok.

The California vanagon has a full throttle switch and a speed limit switch. When the engine is warm operate the full throttle switch by hand and it should go up 100 rpm. If it doesn't then you need adjust it.

Don't give up.
_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

Yellow Van · Posted: Mon Apr 13, 2009 2:05 pm Post subject:

Thanks. The intake elbow was cracked in a few places and showed evidence of a silicone substance over it as a repair. I added some more sealant to newer cracks I found in the elbow. I would like to replace it but don't see new ones for sale anywhere.

I suspect the EGR valve is leaking as some exhuast smoke came out of the hinge area when the van was started after the gaskets were replaced. Again, not sure where to find a repalcement for that.

I'm not familiar with the speed limit switch. Can you tell me where that is?

Also, I have been wondering what the long spring that goes from the throttle to the middle of the intake manifold is. I can't figure out what that is for.

Randy in Maine · Posted: Mon Apr 13, 2009 3:16 pm Post subject:

Use some "shoe goo" on the S boot.

Show a picture of the spring you speak of....

M_atthewanderson · Posted: Mon Apr 13, 2009 3:21 pm Post subject:

That spring is for the back tension on the throttle.

Image may have been reduced in size. Click image to view fullscreen.

RCB · Posted: Mon Apr 13, 2009 4:50 pm Post subject:

The small rubber elbow exiting the auxillary regulator is available from Bus Depot and its part number 022-129-637...cost a few bucks.

I found a NOS "S"boot online a few months ago part number
071-129-967.

Keep searching...you just might luck out as I did. Make sure you have a tight fit on the two plastic connectors that exit the boot.

Make sure the top to the air flow meter is on their tight too, no gaps to let extra air in.

Thankx to a fellow Samba user who posted this area of concern

Yellow Van · Posted: Mon Apr 13, 2009 9:15 pm Post subject: New findings

I found two rather interesting results today. One is the negative battery strap itself has 18 ohms of resistance. The resistance at the engine is about 20 ohms everywhere I tested. Could this be the source of my problems?

The other is my EGR valve is leaking A LOT of exhaust from the hinge where the lever pulls the plunger in right into the engine bay. I can't imagine this being good! It passed emissions in September so I think this is a newer problem.

The Temp 2 sensor is putting out 1500 ohms at 60 degrees Fahrenheit.

reluctantartist · Posted: Tue Apr 14, 2009 6:56 am Post subject:

You are missing a vacuum line on the distributor. Look at the vacuum advance and you should see a nipple on the back side, I do not remember exactly where it connects but you have a loose vacuum line somewhere. If there is no nipple there then you have the wrong distributor. California vans had connections for vacuum advance and vacuum retard.

If you open the the throttle lever all the way it will hit the switch...it is black with a metel lever that is hit when the the throttle is wide open.

Look at the rubber Y that looks like it may be leaking as well.

On the EGR valve...I took mine off since I do not have to get mine smogged. They didn't have one in 1980. Take a look on the gaskets again and make sure it is not plugged. Also is the pipe in good shape as well as the filter by the heater box (they often rust out).

You are getting close....the vacuum from the distributor will be the biggest help and may even make it run ok when fixed since the lambda system will correct for the rest, but get the other issues fixed as well...your mpg will be happier.

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_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

Yellow Van · Posted: Tue Apr 14, 2009 9:09 am Post subject:

reluctantartist · Posted: Tue Apr 14, 2009 10:33 am Post subject:

sorry about that, if only it were so simple as the vacuum hose. Did you check the vacuum canister in the distributor....the simple way.... attach some clean hose to one connection at a time and suck on it to see if the actuator (inside the distributor not sure exactly what it is called) moves the correct way?
_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

iceneweb · Posted: Tue Apr 14, 2009 6:23 pm Post subject:

I don't know if this is any help, but on my van i found the connector for the O2 sensor to be so corroded that i had quite a time getting it apart. If you can trace your 02 sensor and temp sensors as far as you can, undoing each connector and getting in there with some abrasive paper, tightening up the connections and spraying them with WD40, you might see a result.

After doing the above, and cleaning all grounds i have not had a recurrence of my van's hesitating and loss of power.
_________________
Thanks,
Mark

1959 Volkswagen Panel

Yellow Van · Posted: Sun Apr 19, 2009 5:54 pm Post subject: Bad grounds!

Power is back and not a trace of bucking or surging!

It seems my problem was due to bad grounds. I cleaned up the existing grounds and added another 4 gauge ground wire to top of the motor. The engine still shakes at idle but runs smoothly on the throttle and has reasonable power, which is not to say it is fast by any stretch.

Also I just got a set of Hankook RA08 tires. WOW! WHAT A DIFFERENCE! The van rides better, is much easier to steer, handles better, and has great grip now! Very much a welcome change.


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Vanagon Syndrome like condition on Air Cooled?
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