Auxiliary Air Valve Necessary?

[Artfrombama]

My 73.5 had the auxiliary air (deceleration) valve removed at some time before I bought the car. Car runs well and otherwise everything operates properly.

I've noticed lately if I come off the gas abruptly the engine dies, not too much a problem, I've learned to work around it. AC on makes the problem worse.

Would the deceleration valve remedy this? Obsolete part, very pricey NOS or used are my choices.

Thanks!

[E Sully]

Here is a basic description from the CIS primer.
911 CIS Primer - Components
I would replace it, it should take car of your issue.
You might want to contact Tony, Pelican Parts Forums - View Profile: boyt911sc
He knows a lot about the cis and might be able to help with replacement.

[stlrj]

Then why not put it back on and let us know what happens? The worse that can happen is you might just save a ton of moolah.

[boyt911sc]

Originally Posted by Artfrombama

My 73.5 had the auxiliary air (deceleration) valve removed at some time before I bought the car. Car runs well and otherwise everything operates properly.

I've noticed lately if I come off the gas abruptly the engine dies, not too much a problem, I've learned to work around it. AC on makes the problem worse.

Would the deceleration valve remedy this? Obsolete part, very pricey NOS or used are my choices.

Thanks!

Art,

You are not talking about the AAV (auxiliary air valve) but the decel valve shown in the picture? All 911 CIS have this decel valve except those with lambda/OXS with a different decel valve. People disabled them simply because they did not understand how it works. The lame excuse was it’s for emission only. Emission was not a factor in 1973 and carburator equipped cars were still being produced. Remember that CIS was the #1 system in the world in ‘70’s~’80’s until the introduction of EFI system.

Going back to the subject, you need to find someone who knows CIS or if you want to do it, there are plenty of help available from this forum. You can find a used good decel valve for less $100 if you decide to install one. Just make sure you install a good working DV. It would take only a minute to test a decel valve. Keep us posted.

Tony