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Wed Jul 16, 2008 8:33 pm

here's the details on my friends ride...2.1L '87 westy...normally in FL but he travels up the East coast during summer...he says in the mountains in vermont he ran into this problem...once his engine gets warm the engine seems to lose power and almost stall at idle. My thought is the ethanol in gas or the altitude change...should he switch to higher octane or just adjust the timing or both...help?

Thu Jul 17, 2008 11:33 am

from my experience - I live in denver 5300 ft and have driven many cars up to the mountains here, and very quickly you will notice dramatic performance losses with altitude climbs. Lower idle and the car needs more pedal. I have experienced this with old ACVW and new cars of various makes

Thu Jul 17, 2008 4:34 pm

I understand about the performance loss but can this be fixed by adjusting the timing or something else or does my friend need to just deal with it and put a little pressure on the gas pedal when idling

Fri Jul 18, 2008 3:49 pm

There is something in the Muir book about adjusting the timing so many degrees per 1,000 ft. above 5,000 feet or something, so maybe its worth just advancing a degree or two, and then dropping back to the original setting when he is on his way home.

Or for a quick fix, maybe turn up the idle to like 950 rpm.

Fri Jul 18, 2008 4:06 pm

You can have a few items giving you grief. First, the Temp II sensor, replace it. It is like James Bond, shoot him, shoot him the second you see him, most of all don't tell him your plan!. Temp related issues, it is the first source of trouble, cheap, get it out of the way. The coil gets weak when old and hot, producing a poor spark. The Vanagon likes a healthy spark, speaking of which. How old are your ignition wires? The fuel pump and fuel pressure regulator also get funny when hot and at altitude. Perform the checks and see if they are within specs.

Advancing the ignition of a computer controlled ECU driven ignition is not what you want to do. On the old vacuum advance systems this worked. The Digifant uses an ignition map, so the advance varies depending on many factors.

Read through the 86 Vanagon Protraining book to understand how your van's electronics think and react to the world. Then go through the other Protraing manuals to perform the check of the ignition system, fuel system and sensor testing.

In your testing, do pay attention to the Throttle Switch. If it sticks (which can be heat related as well), the van performs like a dog.

Buy a Bentley or download the ProTraining Manuals.

if you want your own set of Protraining manuals for free, go to my public folder and get:

86 Vanagon Protraining.pdf
Vanagon Protraining 86-91 Fuel Systems.pdf
Vanagon Protraining Digifant I 86-91.pdf
Vanagon Wiring Diagram.pdf

http://homepage.mac.com/WebObjects/FileSharing.woa...mp;lang=en

Fri Jul 18, 2008 4:15 pm

Call Craig in Colchester VT if he needs help. Honest guy. 802-951-5977

Sat Jul 19, 2008 6:13 pm

Altitude will rob power dramatically, but normally idle shouldn't be lower as a matter of course. Plus that van has an idle stabilization system that should be able to compensate at the low altitudes you could get to in Vermont. So something else is up.

The base mixture in open-loop or without o2 sensor may need to be reset a little richer. There is a table in Bentley FI section correlating base mixture as measured by CO to altitude. If that is correct then it should be in range where the o2 sensor can fine-tune mixture.

As a general rule you advance timing 1 deg for every 1000' over 4000' in altitude. But nywhere you can drive in the East you're barely at this threshhold. Plus the Digifant doesn't seem to respond to this compensation as noticeably as other cars with vac-compensated dizzys. I would probably leave this alone other than to verify that base timing is right while checking the CO.