On return style fuel rails that have the little regulator on it, do you have to have a vacuum line hooked to it? What happens if you don't have it hooked up?

 

Yes you need a vac lined hooked up, other wise it will not work correctly based on engine rpm and all..

 

Ok does it increase pressure with rpm is that how it works? I'm just curious

 

Correct.

 

Well I got my truck back going after the 6.0 swap and I been driving it a few days and I noticed high rpm it kinda surges slightly and doesn't build rpm and I bet that has something to do with it. Ill hook it up tomorrow and see.

 

what did you find out?

 

I hooked a vacum line up to it and fixed the problem. Then today I was out driving and I noticed when I kicked it down and it got lil under 5k it just didn't pull right didn't build rpm like it should. Before I put the vacum line on it wouldn't do right at all anything above 4500 but now its just after it has been ran awhile so I believe now my fuel pump is going but it has been whining for awhile now. I'm going to check fuel pressure and see when I get time.

 

cool beans... thats where i would start as well... make sure you dont have any other vacuum leaks as well... starting fluid helps find them

 

The vac line on the fuel pressure regulator does nothing at wot, without the line it will run 60 psi and with the line it's gonna run 60 psi . Put a fuel pressure gauge on it and see if ur dropping under 60 at wot.

 

Well I put a new pump in today and fixed my problem. I didn't ever check fuel pressure because it got worse were it would turn just around 3k at WOT and the fuel pump was whining bad and changing pitches. It just didn't sound good. Now it is nice and quiet and working like it should. I wish I did own a gauge to check the fuel pressure to see what it was pumping. I'm just glad it is fixed and it sure does run better.