This is my first post as a paid member! Feels good! Never knew that membership was so affordable and easy to process (never bothered to check!). Perhaps if the price of membership is posted up front on the home page then more people would join!

I’m starting to refurbish the intake and clean the injector and noticed that there are two vacuum connections at the bottom of the intake manifold, and only one was connected meaning that the other vacuum connection had no line connected to it nor did it have a blank cap to seal it! No wonder the car was idling rough! Can some one tell me what the second connection is for?

Thanks, Azir
87 S4, Auto, Cup 1.
96 XJ12

 

Hi Azir,

I recently did this on my 90 GT and it has only one connection on that side.
Not sure what the second was for?

There is however two on the opposit side, do you have tha same?


Cheers/Peter

 

The second one is blocked off at the rear of the engine. I do not know why or what it was for but I've never seen it connected to anything.

(It's a great place for a vacuum/boost gauge!)

 

Thank you Peter and Dave, Are your cars Automatic ? Dave you say that the second is blocked off at the back of the engine! how is that done, is there a short pipe with a plug? how long is the pipe and where does it terminate?

Thanks, Azir
87 S4, Auto, Cup 1.
96 XJ12

 

Mine is manual.

Cheers/Peter

 

Azir,
I'm in the middle of my intake R&R as well. That second white vacuum line on my '87 auto, is also blocked off. Goes to the back of the engine, then under the water hose leading toward the vacuum pot that gates water through the heater core, then ends hanging out over the rear of the passenger side valve cover, with, in my case, a hot pink vacuum line cap. This capped line, is the line who's elbow connection, cracked and fell off the vacuum port, on the bottom of my throttle body.

Ketchmi,
Your point of this line being a vacuum/boost port is a good one, here are my thoughts; Great for boost, not quite so good for vacuum, if you wish to monitor for vacuum loss. I'm going to plumb in my vacuum gauge, to measure system vacuum, so I can tell when another vacuum leak is occuring AGAIN!