Why is this part plugged? Done by factory?
 

I bought an early '78 intake system and found this:
A plugged Alu elbow from the rear of the rubber boot on the mixture control unit/throttle body. This elbow normally has a rubber hose leading to the AAR and CSV. I removed the hose to show the plug in the elbow.
The plug is a solid resin material and looks like it was professionally done. See picture.
With the resin-plug, and no air-flow through this elbow, how can the AAR and CSV function?
The seller says that this system passed CA smog.
Has anyone noticed this plug on any other intake? Has anyone plugged this elbow? :confused: http://forums.pelicanparts.com/uploads5/P62300191119631225.jpg[/img]

Anybody?

That's for the throttle plate air bypass on cold start. Won't affect smog inspection at all but will affect your cold start fast idle as you'll get fuel but no extra air unless the thermo time switch and CSV is out too.

tsuter: Are you saying that the resin plug in the elbow is normal for a '78 SC intake? There is no plug in that elbow on my '80 or the '82 engine I just bought. Why is there a resin plug in the '78?
I have to add that there is a second elbow on all the boots for a breather hose going to the oil filler neck.

No its not normal at all. It should be open. Its for the throttle plate air bypass on cold start. Blocking it won't affect smog inspection at all but will affect your cold start fast idle as you'll get fuel but no extra air unless the thermo time switch and CSV is out too.

Now mine is rerouted since I have a turbo and "that" particular locaton is blocked but I draw air thru a port on the back of the throttle body casting itself to supply the CSV and AAR/AAV

Thanks, tsuter: But when you think about it, even with the elbow blocked by the plug, there is extra air to the CSV on cold start coming from the AAR which is open when cold.
As the AAR warms up, it closes, no more air to the CSV which is only squirting for a few seconds anyway.
Still puzzled why the resin plug was installed. :rolleyes:

Nope, If that elbow is plugged no air goes to the CSV,AAR,AAV does not matter if they are open.
That elbow fitting is the air feed for the whole cold start system for unmetered air to bypass the TP.

Like I said it may be plugged and rerouted. I use the old decel valve fitting on the TB. If not rerouted then the cold start is disabled as there is no bypass air supply to CSV/AAV/AAR.

Here is the drawing. Part 47 is the one plugged. That is the air inlet or feed to entire cold start system

http://www.pelicanparts.com/911/911_...8-83/1-7-2.JPG

It supplies unmetered air to the AAV, and AAR and then to the CSV port on the airbox to bypass the TP on cold start

Thanks, tsuter: I'll look at it again, the CSV air supply may have been re-routed through the old-style Dec. Valve from the throttle body.
Still puzzled why the elbow was plugged; it was neatly done with a solid resin; very professionally. It would have been so much easier to leave it open so the AAR/CSV can get a direct air supply from the boot. Hmmm