Bman2000

can someone explain this to me a little. I get the concept of one line pressure being controlled basically by the activity of the pump. and i sort of get how the pprv valve worked t keep pressure in the line, down side being spikes in fuel pressure causing fueling issues and hesitation in supercharged and turbo cars....and in some cases like my na car...lol anyway. So what im trying to figure out, is there is a split in hose right before the basket one where the pprv hose when into the basket and the other is to the pump. so what is at the bottom of the basket that the pprv went to? is it a metered hole? i ask because i blew that hose off, and im not feeling to confident about hooking it back up, so i figured if its metered i would just add a fitting and drill a correct hole, if its plugged them ill just plug it, but i cant figure out where it really goes and what its there for? can anyone fill me in?

cliffyk

I only have hand's on (hands smelling of gasoline that takes days to wash out) experience with the Cobra dual pumps, in which the PPRV (Positive Pressure Relief Valve) is intended to perform two functions.

The first is that is incorporates a check valve to prevent the fuel line from draining back into the tank when the engine is off, the second is to provide a relief valve (at 60 to 70 psi according to sources I have) to relieve excessive line pressure (as might occur if the throttle is suddenly "chopped") by bleeding fuel into the tank. The bleed port is not directed via a tube that I have seen, it just blows off into the tank.

The problem in high volume applications is that between shifts, etc., the relief valve cannot close fast enough causing a momentary drop in line pressure, and a lean condition as a result. Removing the PPRV eliminates this possibility, however it can/will also subject the pressurised lines to working pressure near to or in excess of it's capacity.

This can be further complicated when "Ideal" style worm gear clamps have been over-tightened and weakened the hose.

Bman2000

i dont have dual cobra pumps, just the single gt pump. but the reason i asked was because after i removed the pprv line and used a regular hose. i had it hooked up but it blew off, no surprise i suppose, but that leads me to believe that it doesn't just drain back to the tank, cuz i couldn't get the car to start with it draining open to the tank. I also used the correct fuel injection clamps, the smooth ones not the standard hose clamps.

teej281

Just go return. lol Much simpler and more reliable.

justinschmidt1

+1
returnless is a fail, go return

Bman2000

outside my budget, since really i will barely be able to finish scing it...so upgrading the fuel system at this point is a negatory.

Bman2000

besides one pump in a returnless system is plenty more than my stock rods can handle