randyrap

I've been having some difficulty with my idling. It was suggested by a few that I get rid of the AAV as it has no real purpose and could be causing my fluxuating idle problems.

Is this an advisable thing to do?

Thnaks ................................... Randy

mikemdd

I am probably in the minority, but I am a firm believer in keeping as many of the original components as possible. The car was designed as a "system" (generally) and many components interact with others in sometimes unpredicatable ways. Everything has a purpose, or it would not have been engineered into the systme. Some would argue that the purpose is questionable. I think many of the problems people have with CIS systems is of their own doing....they have removed so many things that it is impossible to understand what is going on. I just replaced the auxillary air regulator on my 1981 SC with no problems. Runs perfect with all components intact. Just my lone opinion.

pjc

Many in the UK blank off the AAV because it can give extra horsepower. Can't see the problem myself - just keep the bits!

PJC

randyrap

Now, when disconnecting the AAV, do I plug the 2 main hoses or connect them together? What about the small vacuum line?

Thanks ............................... Randy

Pat S

This is false. The AAV works as follows:

When the engine is cold the AAV is open. This allows small amounts of air to enter the intake around the throttle body. This raises the idle slightly.
When the engine or the bi-metal strip warms, the vavle closes and blocks off the air.
So you will never gain HP by removing the AAV.

There is a simple way to test the AAV.

Start the car. When cold, pinch the hose either to or from the AAV. The idle should drop slightly. Wait a few minutes and let the engine wam, pinch it again and the idle speed should remain unchanged.

If you do remove an AAV you want to plug both ends of the hose so air will not go into the engine unmetered.

Pat

mikemdd

Also, be careful to insure you are talking about the Auxillary Air Regulator (AAR), which I believe is what Pat is talking about, and the Auxillary Air Valve (AAV), which is different. In neither case is horsepower involved at all.

Pat S

Good point mike, different books call them different names, I'm used to the AAV term but according to this page:
http://members.rennlist.com/jimwms/CIS/CIShome.html
it probably should be AAR.

Jim @ EuroWerks

Thats funny, I always called #9 a decell valve. Because when it hangs up the car doesn't decell. Then you crush it a couple of mms (like the bulletin states) and it works great!

mikemdd

I used to always get confused on the AAR and AAV until I had to buy one. Ouch! My 81SC takes a "special" AAR that is no longer made (apparently). It looks similar to other models, but has a different Bosch number. To make a long story short, after calling all over when my turned out to defective (testing exactly as Pat says), if found a new one....$375!! Anyway, everything now works perfectly. Great warmup idle speed, decreasing after a few minutes to spec levels.