Ok I sent my injectors out to get cleaned. While they were gone i went ahead and replaced all my vaccum lines. Now for some reason I cant remember where each line goes to on the UIM. I did look in the FSM but theyre drawing is not very clear. I also did a search on here but most everything I found was with emmisions and rats nest removed which I did not do....Yet.

My 1st question on the vaccum lines is the 4 nipples on the firewall side:

1.??
2.??
3.??
4.is conected to the vaccum spider on the oil injectors correct?

My 2nd question is:
The larger nipple on the firewall side of UIM is connected to Brakebooster correct?

Sorry if this has been answered befroe but i couldnt find anything other than emmisions stuff. and rats nest removal

 

Mine is also an S4, but has only 3 nipples.
The thick one is for the oil injector spider, I think that is the 3rd/bottom nipple.
The one above it should be the primary injector air bleed. The one above that should be the secondary injector air bleed. But... I don't think S4's had that? On mine (all emissions gone) I am only using the primary air bleed and the OMP spider. The other (top) I capped.

 

This is correct. It's the much larger one that is located adjacent to the ones that are aligned.

 

the very bottom nipple is a vacuum source that is used for the double throttle system from the factory. you can hook up a boost gauge to it or cap it off

 

ON my series four TURBO engine there are four nipples one above the other. The bottom nipple is the ONLY one that has vacuum. IT goes to the water thermo to the left rear of the engine.

One of the four nipples that are one above the other, is larger in size. IT goes to the oil injectors spider to feed it metered AIR.

The other two.............either one can go to the nipple b/t the two oil injectors on the intake manifold. That is the fuel injector air bleed metered AIR.

The top nipple gets capped off. Not required anymore for anything.

I was writing this when ARRG posted the above.

Oil injector spider does not get vacuum is my point. The rotor on its intake *stroke* causes vacuum to be pulled on the spider to pull metered air into the injectors top.

 

Thanks guys, I had to take a break from it for a few mins. Once i did that and relooked at the FSM i got it lol.

HAILERS: when you say the top nipple gets capped off cause its no used anymore. Is that the Cold start assist? And its not vaccum correct?

 

I forget what it was used for. It does not have vacuum on it. It is metered/filtered air like the two below it. The ONLY one that is vacuum is the very bottom one that ARGH addressed earlier.

I think the name is SUB ZERO ASSIST.