Date: Wed, 10 Sep 2003 22:10:04 -0600
Reply-To: Chad Morris <chad@ALLMORRIS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Chad Morris <chad@ALLMORRIS.COM>
Subject: Re: idle stabilizer: valve, control unit or both?
Content-Type: text/plain; charset="iso-8859-1"
I did not realize the Idle Stabalizer Control Unit could be taken apart and
be re-soldered. I will look into that. Is it hard to get apart?
Also, when you mention the poor contact to the ECU were you referring to the
Idle Stabilizer Control Unit, or did you mean the main Control Unit that
lives under the rear passenger seat?
----- Original Message -----
From: "Wolfgang Ziegler" <ziegler@PRINCETON.OILFIELD.SLB.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 10, 2003 9:30 PM
Subject: Re: idle stabilizer: valve, control unit or both?
> Germain, Chad,
>
> there are probably many causes for this idel instability. Here two of my
> recent encounters:
>
> a) Engine races after startup, then cuts off - would not have enough power
> to drive:
> Long trouble shooting & frustration, finally turned out to be connectors
on
> the idle control unit which had broken solder joints on the board: a
couple
> of the large metal spades cracked the solder and had intermittant/no
> contact (a failure we see frequently in heat cycled electronics):
re-solder
> and all was fine
>
> b) Oscillating RPM (600...1200)
> A combination of poor contact to the ECU (the connections were corroded)
> and a worn air mass sensor (change spring tension by one notch)
>
> Just some hints, solder or change AMS parameters at own risk... :)
>
> Wolfgang
>
>
> At 08:37 PM 9/10/03, Germain wrote:
> >Hi Chad
> >
> >It could be both, it is hard to say. Many mechanic guies change both
units.
> >They are expensive devices. This is why I am trying to fix it.
> >
> >The ISV should read continuity on a multimeter.
> >
> >I am still experimenting on those devices. Here is what I have done so
far.
> >My idle valve (ISV) seems to work OK when I put 12 VDC on it. No power,
the
> >valve is thight closed, with power, the valve open (No humming because
the
> >ISCU is the solid state unit which can modulate the valve). After
changing
> >some composants in the ISCU, I put 12 Vdc on it with the ISV connected to
it
> >and the ISV was humming. After that I put back all the devices on my
engine,
> >and I turned on the ignition key (without starting the motor) I could
feel
> >the ISV humming with my hand. After 10 or 15 seconds, the ISV stopped
> >humming. I decided to start the engine and it started very fine, better
than
> >when the ISV was disconnected but after a while the engine started to
surge.
> >When i disconnected the ISV, the engine was idling fine.
> >
> >I have checked the gas throttle switch and it seems to be OK. Next step,
I
> >am going to clean the ISV with a brake cleaner.
> >
> >Germain
> >
> >----- Original Message -----
> >From: "Chad Morris" <chad@ALLMORRIS.COM>
> >To: <vanagon@GERRY.VANAGON.COM>
> >Sent: Wednesday, September 10, 2003 7:08 PM
> >Subject: idle stabilizer: valve, control unit or both?
> >
> >
> >I am experiencing the ever so common high idle problem on my '89 Carat.
> >Don't hear the infamous hum or buzzing sound coming from the idle
stabilizer
> >control valve (how loud is that supposed to be, anyway?), but if I
> >disconnect the wiring harness going to the valve while the engine is
> >running, the idle immediately settles right down to 850 RPM. If I put
the
> >plug back in, the idle speed stays at 850 RPM, no change. Does this
> >indicate a bad valve, control unit, or both?
> >
> >Aside from replacing with "known good parts", of which I have none at my
> >disposal, are there tests I can perform with a multimeter to determine
> >functionality? Can I apply current directly to the valve with the engine
> >off to see if I hear the buzzing?
> >
> >Chad Morris
> >'89 Carat
> >Salt Lake City
>
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