[Outlaw1]

Originally Posted by Onefast99gsx

Hi guys- i have a question regarding stock FPR's. I found a problem with my vacuum line disconnected last night. It created a lean spot thus got knock as a result. I put it back on took the car out and it blew off again. Put it back on one last time and of course blew off the regulator again. It wasn't until I took it home and zip tied it on that it would finally stay. Looked slightly wet around the tip of the hose too. Not much but slightly wet to the look.

Talked to a friend tonight whom is a mechanic and he said it should not be blowing off like that. He said this is a vacuum line. Is normal operation of this hose, air pressure to the regulator or suction(vacuum)? Its as though i'm getting air pressure to make the hose blow off like that. If it's a vacuum line it should be suction, correct? I have it connected to a nipple on the bottom of my Magnus manifold.

Thanks for any help.

The fuel pressure regulator sees manifold pressure. If you're under vacuum, the diaphram sees vacuum and lowers the fuel pressure. If you're under boost, the diaphram sees boost and raises the fuel pressure. ALL of your vacuum lines see boost when you're under boost and vacuum when you're under vacuum. If you take the vacuum line off of your regulator and see/smell fuel in it, the diaphram in the fuel pressure regulator is bad. If the diaphram is bad, your car will run like crap.