2004 GTO LS-1 engine question, what is this line for ?

[Tim john---]

Good morning all, I have a 2004 GTO LS1 engine that I am installing in a first gen Firebird. Computer has been re-flashed (by Speartech) as a standalone system, original wire harness reworked (by Speartech) for stand alone as well. While laying out the fuel lines I have the supply line to the fuel rail and there is another line lying next to it. I assumed this was a return line but was informed the GTO was a return-less system. This line exits the intake manifold right behind the throttle body on the driver’s side. Can someone tell me what this line is for, where it goes, is it necessary in a standalone engine. On the backside of the engine this line takes a slight turn towards the center of the engine just like the fuel supply line so it headed in that direction, there is also a (green) capped Schrader valve (like on a tire valve stem) on this line, perhaps for diagnostics, pressure charging or adjusting ? Any help identifying this line would be helpful. Thank You.
Tim john---

[Z06vet]

Something doesnt sound right about what youre describing. Can you post up some pics so we can see what youre working with? If you're using a vaporworks/5th gen GM camaro pump, you can run a single line from the tank to the fuel rail. Otherwise you'll need to use a C5 corvette fuel filter/regulator between the tank and the fuel rail. Most times its mounted close to the tank so only a short return line is needed between the filter/regulator and the tank. Then run a single line from the filter to the rail.

[Tim john---]

My current set up is a Rick’s F.I. tank to a new C5 regulated filter (supplied by Rick's tanks) then to the engine fuel rail, a short return line from the regulated filter goes back to the tank. All this is sorted out. My problem/question is what is the other line on the engine that lies next to the fuel line for. It comes out of the intake right behind the throttle body. Engine is 100 % factory stock. I am not quite sure on how to post pictures to this thread but if you can provide an email address I can send them to you to take a look at or post. Thank You very much for trying to help out.

Tim john---

[Z06vet]

It sounds like either a PCV port or EVAP from the emissions system. Sounds like you have everything set up correctly
Scott