idle problem
 

Hello,
I was hoping on getting some advice on a problem I have encountered recently. I have an 83 911 SC Cab...In the cold morning, the car starts fine, idles normally...

After I drive to get coffee, however, at the local Dunkin Donuts ( about 5 minutes from my house), I get in my car, start the car, and the idle stays at 2000 RPMS....

After I drive for 1/2 hr and the temperature goes to normal operating temp., then at the stop light, the idle is normal again...at 900 RPM...

Could I have a faulty Auxiliary Air Valve?

Hopefully someone with a similar problem can give me some advice. Thanks in Advance.


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'83 911 sc cab euro

My 83 SC idles about 1800 to 2000 until fully warm, then settles in at about 900. New York climate may have a lot to do with the time it takes for it to warm up. 5 minutes isn't enough for mine.

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Robert Stoll
83 SC
83 944

Sounds more like a faulty Aux. Air Regulator (not the Aux. Air Valve). To test, take the regulator off and put it in the freezer for a bit. The opening should now be wide open. Then apply 12V across the terminals. The opening should close completely within a few minutes (I can't remember how long).

Another possibility is the deceleration valve (I'm not sure the euro cars have them). It looks like the Aux. Air Valve, but also has a small vacuum line attached. Just dettach and plug the vacuum line.

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Graham Archer
83 911SC Cab

My car does the same thing, when the temps are cold (around 20F). Your car has two devices that increase idle when cold. The aux air valve, and aux air regulator. Sometimes they are both called the same thing. One of them has an electrical connection, and will close when an heater heats up the internal bi-metal strip. The other does not have an electric heater, and will take a long time to warm up. It is not tightly coupled to the block, so it relies on the ambient air inside the engine bay to warm up. On cold days this can take a very long time.

http://members.rennlist.com/jimwms/Auxairparts.jpg

The item on the left is the decel valve. Next to it is the aux air regulator (has an electrical connection), on the right are two different aux air valves.

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Bill Krause
'79 911SC Euro

Bill,

I'm not sure about your identification of the parts. The item on the left looks like the vacuum control for pre 78 systems. A nice reference for CIS systems can be found at: http://members.rennlist.com/jimwms/CIShome.html



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Graham Archer
83 911SC Cab

Graham - that's where I got the photo, and the description of the item on the left. I'm not familiar with the decel valve, so you may be correct.

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Bill Krause
'79 911SC Euro

Thanks for all the info...I will take out the valves and have them checked.

Driving up to NH this weekend so I will do it once I get back. Gonna do some mountain driving...it was a blast over the summer and it will be cool with all the snow around. The engine definately runs cooler (and stronger) in the winter. It's too bad most POrsches are stored during that time.

I drive my car every day, everywhere, every chance I get....I RARELY see another 911 out there on the road, esp. in the winter....That's kinda sad http://www.pelicanparts.com/ultimate/frown.gif



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'83 911 sc cab euro