Ed:

I have had the exact same problem you describe in my '87 Wolfy for the past two
months. Less than a week ago I joined this mailing list, and after consulting my
Bentley and asking the advice of this group, I took five minutes this morning
before leaving for work to fix the problem. Maybe it's not a long-term fix if you
live where it's cold, but it should be fine for the warm months: I removed the
idle stablization unit. It's behind (in front of, depending on how you look at
it) the right rear taillight. After doing so, I started my bus, kept my foot on
the pedal for just a minute until it warmed up, and then let her idle peacefully
away at a smooth 1100 rpms.

As I understand it, the idle stabilizer keep the idle up while the engine is
cold. Good think it's getting warm out . . .

Chad Knutson
Minneapolis

Ed Carroll wrote:

> I'm very glad to have found this resource, and I hope someone on the
> list can help.
>
> I'm a new owner of an '87 Westy 1/2 camper. PO claims engine is
> factory new 40K miles ago, but I'm fairly sure, based on appearances,
> that the manifolds and injection system are older, perhaps original.
> I've put less than 1,000 miles on it since I bought it, and have done
> little work on it, as it's been too snotty out to explore it.
>
> Just recently it began idling way too high as it warms up, building
> to probably close to 3,000 RPM over  5-10 minutes from a cold start.
> Starts just fine, but as the idle speed builds you can't knock it
> back down again with a kick to the accelerator. Sometimes I can pull
> up at a light and it will be idling near normal, but will increase as
> I sit there. Fortunately, it's a short commute. When it's had time to
> come to full operating temperature, which is not every morning this
> time of year, the idle has occasionally surged up and down by itself,
> up to 3,000 (or so), then falling back to 1,000 or so, then swinging
> up again. I don't think that's right, eh?
>
> Bought the Bentley manual, which offers great detail but little of
> the working principles of the injection system. (Digifant, if I'm
> reading it right.) But because there is an "idle stabilization valve"
> and corresponding control unit, it seems appropriate to start there.
>
> So, the questions:
> 1) has anyone had similar experiences, and how did the troubleshooting go?
>
> 2) can anyone explain in 100 words or less what the idle
> stabilization valve does? Other Bosch injected vehicles I've had
> didn't have one (that I'm aware of.)
>
> 3) Should I also buy a Haynes manual for a better description of the
> injection system, or is there another that addresses it better. I'd
> especially like some kind of troubleshooting flow chart to organize
> my thinking around.
>
> 4) Should I become immediately familiar with the best VW mechanic I can find?