Another - "what is this?" question
 

I recently bought a 1981 911SC and I'm going over all the issues I can find. One item is hard for me to identify.

On the right side of the motor. Below the airbox is some metal unit that seems to be mounted to the upper part of the motor itself. Could be an oil pump, regulator or vent system. But I could not find it on the fish diagrams.

Previous owner seems to have blocked it off with some kind of red cap (1) and bolt in the pipe (2)... very strange? Anybody know what this does and why they would block it off??

http://forums.pelicanparts.com/uploa...1279734794.jpg

#1 is the AAR (Auxiliary Air Regulator) that allows air to bypass the throttle body during a cold start. It raises the RPM's until the engine warms up a little then closes allowing the RPM's to drop to normal. They go bad and people just block them off or remove them. I don't know about #2 but it looks to be an oil line.

I think #2 is the line that went into #1

LOL! this is a great fix!! Oh boy are you in for some fun. #2 goes on #1 however it doesen't look like #1 works very well. How is the warmup idle? does it run good when cold? I bet not. There might be a few other vacuum leaks in there so the PO might have closed off as many as he could have. Or the AAR is bad (stuck open) and this fixed it. Who knows. You came to the right place for info.

I like the plug!!

Thanks everybody!! This is great info. I feel much better now. I live in south florida, it is damn hot here, most of the year, so I dont really have a need for higher idle speeds at startup. In fact I just removed the heater blower as well. No need for it down here in paradise... ;-)

So I am going to leave the jerry rig just as it is for now.

One reason for the AAR is to prevent air box explosions when the motor snots up on a cold damp morning. You do get those now and then, don't you?