fuel delivery

[bohmankid]

My motor is a 2001 5.3 with the return line on the fuel rail at the manifold. Quick question, is it possible to have too large of a return line? Both my main line and return line are stainless braided 3/8" (-6an) line. My pressure at the rail is 47 psi at idle, is that normal? It has a new walbro 255 pump, new lines, new trick flow filter, new regulator.. the truck runs ok, but I haven't taken it out much.

[Clyde65]

no harm, as long as the lines are rated for fuel. if not, they could collapse.

47-50 is normal, should come up to about 58 when accelerating.

[BR3W CITY]

Nothing monitors the pressure or flow of the return line, it basically just pee's into the tank when it has extra fuel. As long as the fluid in the return line can make its way to the tank, your all good. I guess if you had a 1" pipe or something the pressure could be so low in the return that the fluid couldn't make its way all the way there...but thats insane in the first place.

[ls1nova71]

47 seems anlittle low. What does it go to when you pull the vacuum hose off the regulator?

[bohmankid]

Thanks for replying guys. When I take the vacuum off the regulator it jumps up to 55 psi. I wish I had a way to watch it while driving.

[bohmankid]

Also, when I put it in drive and hold the brakes while pushing the gas, it'll go from 47 up to 55-56 psi. So I guess it's all good? I can't drive it yet because it needs new tires, but gassing it while breaking should simulate driving under a load, I would think.