TheSamba.com :: View topic

Sat Jul 16, 2005 11:18 am

I recently got my van ('87 Westy) back from the shop and in checking over the engine i noticed the idle stablizer unplugged (the part that sits on top of the engine). When I plugged it back in and started it up, the engine revv'd up and down continuously. With it unplugged it runs fairly steady. Something tells me this is a bit odd but then again I know next to nothing on this topic. Is it a problem if it's unplugged? Is it common for people to unplug this component? If so, why? We're about to go on a big road trip to down into the mountains of California so trying to trouble shoot anything out of the ordinary up front. Thx for your help.

Brad

Sat Jul 16, 2005 10:40 pm

I used to have to unplug mine on my '86 . When is got hot, it would start racing at idle to like 4000 rpm. Unplugging it was the only fix. It was an intermittant problem and I never found a mechanic who could figure it out. There was never a problem until it got hot. Hopefully someone has a fix for you.

Sun Jul 17, 2005 4:59 am

Bypassing (Unplugging) it is a way to troubleshoot it. Most people leave it unpugged when it goes bad because of the cost of a new one. If you want to fix it correctly you get a new one. If that is what your mechanic calls fixing it, I'd look for a new one(mechanic).
Here is the part: http://busdepot.com/details.jsp?partnumber=251907393D
you can put it on yourself.

Sun Jul 17, 2005 10:55 am

right. thx guys. appreciate the help. i knew the price of a new stabilizer unit was high and was hoping to avoid spending the $$. stupid question but is there any real loss for leaving it as is (unplugged) or should this be a 'must replace' scenario? i just want to make sure i'm not stranded b/c of something i should have taken care of.

cheers,
brad

Sun Jul 17, 2005 11:47 am

May never cause any real problems, you may have trouble idling if you use the A/C. If you start having erratic idle problems or stalling you may want to get a new one quick. look around for a used one, but I would think about replacing it in the future.

Sun Jul 17, 2005 5:12 pm

Take it off, clean it out with O2 sensor safe throttle body spray. Should work like new again. I have yet to see one fail to the point it cant be cleaned out...

Sun Jul 17, 2005 5:18 pm

Professor Reed is that the reason the idle will go up to about 1800 and sit?
Or fluctuate at an idle from 800-1000 and so on?

Is it that nasty compensator that is messin with my head?

Sun Jul 17, 2005 5:27 pm

Yup,

Also a lot of times the cause of a no-start or stall at idle...

Sun Jul 17, 2005 5:31 pm

Dang....for a year now I figured it was just a cranky Vanagon.

Does do dat....idle and starting and stalling... :cry: :cry: :cry: Warmed up it runs at 1800, but you can drag it down to an idle with the clutch then it slowly goes back up

I got 24mpg the other day in it...so something must be right

Sun Jul 17, 2005 5:33 pm

Oh, it will run just fine, really has nothing to do with MPG, more or less its just letting a little air bypass the throttle (running a little lean I guess..) 8)

Mon Jul 18, 2005 11:06 am

hey dan, just so i understand you correctly, are you suggesting i clean the idle stablizer assembly on the top of engine (where it's unplugged) or remove the idle stablizer unit itself and clean it up? or both? also, can i get the throttle body spray you refer to at any auto store? any brand you recommend? thx again for answering all the questions. much appreciated!

cheers.

Mon Jul 18, 2005 12:01 pm

Are we talking Digijet or Digifant?
Is it the little funny round tube thingie?
It is a little motor.
If it is the little motor kind, the commutator inside wears out and causes jumpy operation.
Most often it is full of oil and sluggish.
Cleaning helps.
But, if it is the commutator then it is worn out.

My Digijet van is doing this exact thing.
Runs fine cold.
Idles up when warm.
Sometimes blipping the throotle helps.
Cold stalls sometimes.
But, it does not have the idle air stablizier valve.
I have not looked in some time, though.

I guess I gotta go look....

Mon Jul 18, 2005 1:24 pm

That's what I'm talkin about - Digifant. Lots of Euro Trash uses the same part (BMW, Volvo, Saab.. VW.. etc..)

Mon Jul 18, 2005 2:19 pm

YEP. Those kind get sluggish and sticky when oil builds up in them. You can clean them out and oft times they are OK. They also wear the commutator out. Moving back and forth across the same point a groove or pit is worn in. Then it is basically done and you need another one.

I'd go try some of the bigger wholesalers for that thing. It is generic enough that you ought to be able to get it for a lot less than 300+ bones.

Now I dug my 85 only (Digijet) schematic out and there is an auxilary air regulator which I think is for cold start like a choke. Kinda like what CIS and CIS-E use. I do see and idle switch and a full throtle switch which my current throttle body does not have. But I got a nice fresh clean one that does. Too bad, I can't find the wires for it, yet. It has an idle stabilizer box in series with the hall sender. That type used to go bad and you just by pass them by putting plugs together. So the Digijet does NOT have the same type of idle motor air valve for idle stablization. A good thing. Now I just have to see how it deals the A/C......Emmm....Maybe there is an air valve like other cars. Some also had a low idle extra valve too. Emmm...Might need some of those. UGH...here we go....

Mon Jul 18, 2005 2:26 pm

Digijet just bypassed metered air into the plenum to boost idle speed at "cold."

Nothing special but it can get "gunked" up. Pinching off is the diagnosis, change in idle speed (or stabilization of freaky idle) means it is mis-behaving.

Mike!

Mon Jul 18, 2005 8:54 pm

ok folks, cleaned out the indle stabilizer valve as instructed by dan. gunk did run out but not as much as would have expected from the readings/postings. nonetheless, reinstalled the part, plugged everything back in, fired her up and...well, things were good for about one minute. then back to the same shenanigans as before. idled high (engine was warm already) at 1200 then revved up to 3000, then down to 1200, repeat, repeat, etc. any other suggestions?

Tue Jul 19, 2005 5:46 am

It could be worn out as r39o suggested. Are there any test that can be done on the bench? Are any of those used on the A2 or other cars?

r39o, my '85 has a silimar idle problem to yours. Turned out that the throttle pos switch was not closing (ohm meter not at infin) Took it apart, cleaned and repositioned the stops. Now, all is well. Even has better engine braking.

Tue Jul 19, 2005 6:21 am

Ok, yes, the A2 cars took the same model. At least the 87 and up ones did.

Check your throttle switch setting, if someone messed with the hard idle stop (the throttle plate), or the air bypass screw, OR the Co setting - the van will be very confused and attempt to "hunt" for the right idle.

You may want to look at this..

http://members.bellatlantic.net/~blumax/

Tue Jul 19, 2005 6:53 am

before I yanked my 2.1 I delt with this. turned out to be the control unit, not the main brain but the little one near the passenger tail light. unplug it and run her. if nothing changes that could be the cause.

Tue Jul 19, 2005 8:44 am

buspor63,

Seeing how there are NO switches on my throttle body, maybe that's why I have issues! My mechanic buddy told me it looked like someone had messed with the throttle body. I got another one, took it apart some, cleaned, bead blasted, lubed and now it is together again including idle and full throttle switches. Next trick is to locate the wires! It is not obvious where they got stashed or cut at.

Before I stick it in (something I normally let the girls do!) I need to buy a new seal, I think. Unless it is a commonly reused part?

Idle Stablizer Valve:
Any one of those valves that looks the same will work. They were on A2's, Porsche's, Audi's, Saabs, Mercedes etc. In fact the Japs copied the Bosch system, at least on some Nissans, and I saw some of those parts in those cars too. In the Jap versions, I don't know if the hookups are the same. It is one of those universal parts and spending $300+ on a new one is outragous. You should be able to get a new one at one of those local discount places. Here in San Diego we use: Inter Auto Parts. You could try Worldpac, IMC, etc...