I installed a holley stealthram. I hooked my fuel lines up today, and decided to do a leak test. no leaks. I unhooked the pressure side to make sure gas was going through. Plenty of gas was going to the rails. Gas was in the rails and pressurized, as I opened a shrader valve and lots of gas spewed out. However, when I unhook my return line, no gas comes out. This was all done without cranking the engine over, just turning accessories on. The return line is hooked up to the fuel pressure regulator. Is there something wrong with my fuel pressure regulator and that's why no fuel is coming out? I turned the screw on the back, I screwed it in (tighten) and I had no change. Fuel is supposed to go through the return line, right? I'm just stumped. The fuel pressure regulator is just a holley FPR. anyone got any ideas? Thanks.

Ryan

 

If you short the pump out and keep it running and you still have this, you might have a problem. The pump gets a signal to pump when the car is turned onto the run position for a couple of seconds. This is to prime the fuel lines and get it to pressure. Once that is done, the pump no longer runs and as such, no fuel gets pumped. The regulator is supposed to keep the pressure there and once it exceeds the pressure, let it bleed off into the return line. In that situation, it should not be running out at all. You need to crank it to see anything.

 

The engine was just put in, so not ALL of the sensors are plugged in, and the distributor is not in. I just replaced the hard fuel lines with flexible ones, as well as the new fuel rail and FPR so I wanted to make sure everything was okay before I progressed further on putting the engine together.

This morning I screwed the screw all the way in, and cranked it, and no fuel came out. I unscrewed it all the way and cranked it, a small amount of fuel came out then stopped. the vaccuum port is not hooked up, would that make a difference? I don't believe the oil pressure sensor is hooked up...is that the one on the oil cooler? I seem to remember something about the oil pressure sensor activating the fuel pump. I don't know, I'm rather confused right now. Thanks for looking though

Ryan

 

mine trickles out with the Holley pro injection also. I just replaced the intank unit and took out Holleys cuz it seems to be frozen up

 

In my professional experience it's pointless to try to troubleshoot anything if everything isn't hooked up. Get the rest of the engine together and then try it.

On most cars, if the computer sees no oil pressure then it will shut down the fuel pump to keep from eating the rod bearings. That may be why you got no fuel while turning the engine over. The small amount that came out when you screwed the regulator screw out was probably due to the regulator letting it out to reduce the line pressure.

 

When you screwed the AFPR in, you were increasing the pressure at which it would let off and drain the excess fuel back to the return lines and tank. Like I said, short out the fuel pump and you will see the return line have fuel in it.

 

i would make sure everything is hooked up properly!