CIS question 82 SC. What is this?
 

What is the function of the U shaped, 1/2" copper tube that runs left from from the throttle body, under the heater blower, then connects through a rubber tube into the lower airbox? Does it have a vacuum limiter in it? It looks like it just bypasses the throttle plate, though it has a t in the rubber section that must go somewhere.

Regards,

Jerry Kroeger

Although I still know nothing about CIS, I just happened to replace the hose clamps on that pipe. I didn't see anything 'in' it, but that plastic T pipe is called a venturi tube. I replaced that too because there's an O-ring in it that went bad.

Re: CIS question 82 SC. What is this?
 

hi jerry,

this sounds not as a original setup to me....
there should be a vacuum limiter, and there are two types of it:
a small one, just around the throttle valve sitting at the left side, where you described your 'tube'(i guess that's the type belonging there to your engine), but in this case the reentry is right below the throttle valve.
Or a big one in the anterior vaccum tract together with aav, aar and vacuum booster. it could be possible that somebody wanted or had to get rid of the vacuum booster and built a shortcut to the airbox.
there are quite good technical exploded diagrams at pelican parts, download and study it.


good luck
pomaro