Date: Wed, 17 Aug 2011 10:02:45 -0500
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: All Is Not Well in Air Conditioning Land
In-Reply-To: <4E4BB735.4020300@ip-solutions.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
As I understand it - and my interpretation may be off here so maybe a
more knowledgeable person can correct me - the idle circuit includes the
Idle Stabilizer Valve( ISV - top of the engine) and the Idle Stabilizer
Control (ISC - in front of the right hand brake light), and the
Electronic Control Unit(ECU). The ECU receives inputs from the Temp II
sensor and from the O2 sensor. These inputs change as the engine warms
up. The ECU uses the inputs - and some others - to adjust the idle speed
through the Idle Circuit so the engine does not stall when the AC is on.
I think I have read somwhere that it is set up to kick the RPM up if it
falls below 1300-1500 rpm, preventing the eninge from stalling, say, at
at stop light, when normally the engine would drop back to idle. Of
course if that happened, with the load of the AC on it, it would stall,
so the ECU works to keep the engine running fast enough to create the
horsepower needed to run the AC - which by the way, is around 5 hp.
Make sure all of your vacuum lines are connected and there are no leaks.
Then set the idle RPM per the Bentley. Be sure you remember how many
turns of the idle speed screw you used. You may want to go back to where
you were with it. Check operation after adjustment.
Beyond that - we are paddling the same boat I'm afraid. I haven't
figured out why mine wants to idle to fast, even after adjustments.
Good luck.
John
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
On 8/17/2011 7:42 AM, Harry Hoffman wrote:
> Hi John,
>
> I'd be very interested in hearing what you find out.
>
> I just got my A/C recharged and working (it feels great too) but now
> idle is 1k+ and anything lower and the engine will die (with or without
> A/C running).
>
> Cheers,
> harry
>
> On 08/16/2011 11:46 PM, John Rodgers wrote:
>> After all my excitement about having air conditioning - a new problem
>> has reared it's ugly head. Out of control RPM.
>>
>> After I got my AC system working - I noted the engine idled way to fast,
>> even with the AC turned off. Work associated with the AC effort was
>> getting the vacuum lines connected correctly - which they were not. Now,
>> with everything as it should be - apparently - the engine idles to fast,
>> as I said, even with the AC off. I went through the idle adjustment
>> procedure per Bentley, and with O2 sensor and ISV disconnected, and
>> engine warm, it idled perfect - 850 +- rpm. When I reconnected - the
>> engine died. Repeated the procedure, it will not idle when O2 and ISV
>> are reconnected, I could only get the rpm by adjusting while the ISV is
>> connected - and it is approximately correct but still is a bit to fast.
>> I can leave the ISV disconnected and just run it - which i have done for
>> years, but now I have the AC working, I need that to work in conjuncton
>> with the AC to keep the engine from stalling and it's not happening.
>> Anyone have any ideas?
>>
>> Thanks,
>>
>> John
>>
>> --
>> John Rodgers
>> Clayartist and Moldmaker
>> 88'GL VW Bus Driver
>> Chelsea, AL
>> Http://www.moldhaus.com
>>
>
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