I removed the UIM and LIM off of my s5 NA a little while ago. When I put them back together I was very careful to follow the vac diagrams from F1-6 and F1-7 as best I could. However, I ran into one problem.

There is one nipple on top of the engine, below the primary injectors. The fsm doesn't seem to know about it. Right now I have it routed to a vacant port on the UIM, but I'd like to know where its proper connection is...

 

It's likely the primary injector air bleed. It gets a metered air source (non-vac). Pull the line off of the nipple it's currently on to see if it has vacuum, while the engine is idling. If not, you're good. If it does, swap it to another or tee into something like the secondary air bleeds.