I'm struggling with nearly an identical problem in the AAR on my '79 911 SC. Mine has power, but doesn't fully close. Or open.
There is a fair amount of 'almost' accurate information in this thread. The AAR provides an air bypass around the throttle butterfly.
It is active only when the engine is warm as the supplied electrical power closes the bypass.
It is inactive when the engine is cold as a lack of power causes the valve to close.
It really can't be eliminated regardless of climate. I live in Florida and you will go crazy trying to modulate the throttle while the engine gets up to operating temperature. Cold climates would be significantly worse.
In keeping with the Hughes family motto - it's already broken, isn't it? - I'm going to take it apart and attempt a repair.
I've already douched it out with Carb cleaner with no success. (Yes, 'douche' is the correct word for those of you who are so PC you will have a coronary when you see it.)
And new ones are some $800. Ridiculous.

Aar........
 

Larry,

I agree with the above statements. However, used AAR will work fine if the heater and bimetallic spring are working. Since owning my SC for almost 20 years, I still haven't had the chance to use some of my spare AAR's sitting and collecting dust in my basement.

http://forums.pelicanparts.com/uploa...1264560983.jpg

Since I was stricken by '911 virus' some years ago, I haven't stopped buying extra spare parts (duplicate, tripilcate, etc.) that I haven't touched or used in years. The sickness is so accute to get to the point of having a spare motor, transmission, even a roller (believe it or not) and I won't even mention the parts in boxes. I quess this was a result from overcoming another addiction which many of you already have. That's DE or track time. Please stay away from this addiction.

BTW, the reason I posted was to let you (Larry) know that there's a cheaper way to solve your CIS problem.

Tony

tony,
not the response i expected from you.
larry, you may have just done a typo, it opens when cold. being in florida and not very cold, you may not see a lot of change in open to closed, and i dont think it ever completely closes. remember, the opening is controlled by temp, warmer temps, less it opens. if you are getting and idle change from cold to warm, i would think it is working fine.

Need to elaborate.......
 

T77911S,

You have covered the subject well and there's no need to elaborate it further. Plus I'm quite busy lately because of the arrival of my 3rd grandchild. Another potential Porsche driver in the family.

Tony

congrats, that will keep you busy. i have not tested the AAR as much as you have. thought you might have a little more insite as to the position of the vane verses temps.

I never did like the aar, aav, decel stuff, my 75 still had the hand throtte in it when i did the 3.0 swap, took all that stuff off and have been happy every since.http://forums.pelicanparts.com/uploa...1264622069.jpg
http://forums.pelicanparts.com/uploa...1264622080.jpg

Two things to think about relative to this topic.

1. Those aluminum hoses in Don Gilbert's picture can have leaks too. Your AAV can be working fine and you still have a big vacum leak you can't see because it's behind the airbox. When I ditched all that stuff to put in EFI, I found huge holes that the PO had tried to patch with epoxy.

2. I believe that the AAV is only activated by electric current, not engine heat ( I could be wrong on this ) but assuming that's true, another thing to check is if it's getting 12volts when the engine is running. It's also easy to check if it's working by taking it out and hooking it up to 12 volts and in about 5 min it should be fully shut.

This link goes somewhere crazy?

The old link to Jim’s doesn’t work nor did my bookmark fortunately and thankful it was reposted today - this was in todays thread CIS Troubleshooting for Dummies :

https://cis911primer.com/home.html