Date: Thu, 21 Oct 2010 20:29:46 -0400
Reply-To: Ken Wilford <kenwilfy@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ken Wilford <kenwilfy@COMCAST.NET>
Subject: Re: 91 Carat - Auto Tranny - 2.1L WBX - RPM Hunting
In-Reply-To: <4CC0BEE2.3080300@charter.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
John,
The throttle position switch tells the ISCU when the engine is a idle.
If it isn't working properly then the ISCU thinks you are driving down
the road and doesn't put you into idle mode. Then you get idle
fluctuations, etc. Unplugging the ISV just makes that not work at all
and this will give you a smooth idle after the van is warmed up, however
you aren't properly troubleshooting the system and the van will stall
until warm, when you turn on the AC or go to full chock on the power
steering. Please just take a moment to check and adjust the throttle
position switch per the Bentley manual. It is really not that big of a
deal and should fix your problem. If not at least you know that the
switch is working properly and then you can go from there.
Ken Wilford
John 3:16
www.vanagain.com
On 10/21/2010 6:29 PM, John Rodgers wrote:
> So, Ken, once I disconnected the O2 sensor, and the ISV, the engine
> now runs sweetly through the full range. How is it that the throttle
> position switch is involved? If it was the switch, I would think there
> would still be problems.with hunting. What am I missing in my
> understanding about how the system works?
>
> Thanks,
>
> John
>
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com
>
>
> On 10/21/2010 4:43 PM, Ken Wilford wrote:
>> Check throttle position switch. I beg of you :'(
>>
>> Sent from my Samsung Intercept™
>>
>> John Rodgers<inua@CHARTER.NET> wrote:
>>
>>> Howdy Volks, the saga continues.
>>>
>>> To review - the engine idles at 800-1000, above 1000 rpm up to 1500 rpm
>>> and occasionally it would go to 2000. It hunts up and down.
>>>
>>> Today, I disconnected the O2 sensor, started the engine. On a cold
>>> start, engine started rough, but did run, but it would hunt wildly up
>>> and down to 2000 rpm. Fancy foot work required to keep it under
>>> control.
>>>
>>> After it warmed up, I shut it down, disconnected the Idle Stabilizer
>>> Valve. And started it again. Ran smooth as silk from 800 to 2800. RPM
>>> stayed where-ever I had the throttle set with the pedal.
>>>
>>> Conclusion: ISV is bad. or or the ISC box in front of the right tail
>>> light is bad.
>>>
>>> O2 Sensor may be good. Will hook it back up and try it.
>>>
>>> Any opinions anyone?
>>>
>>> Thanks,
>>>
>>> John
>>>
>>> --
>>> John Rodgers
>>> Clayartist and Moldmaker
>>> 88'GL VW Bus Driver
>>> Chelsea, AL
>>> Http://www.moldhaus.com
>
>
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