I've been trying to diagnose a fuel system problem with this L03 for a while, checked the fuel pump, replaced the FPR, as well as the injectors (somebody had put the wrong ones on, 80 lb/hr), but it's still been running rich

Finally went and installed a fuel pressure gauge, was reading 20psi

Followed the instructions to make the stock regulator adjustable, still nothing, always 20psi

So I think my return line is clogged. I disconnected it where the engine hardline connects to the chassis hardline with a rubber hose, ran a hose from the engine line to a gas can, started the engine, now my FP is 12psi.

So what's the best way to clear a blockage in the return line? I tried fishing a stiff wire through there but didn't really do a whole lot

 

Maybe try blowing it out with compressed air, but if that doesn't work you might be replacing the line.

 

The return and vent lines may be switched at the tank. The line for the CCP vent has a restriction in it. Check each with some compressed air (take gas cap off first). If the CCP vent line flows easily, and the return doesn't, probably switched at the tank.

RBob.

 

all right, think I got it fixed

I don't remember exactly how the lines hook up to the sending unit, but I assume the return line goes all the way to the bottom of the tank? I blew on the return line at the tank (unhooked the short length of rubber hose above the rear axle), and could hear bubbles coming from the tank, but it was extremely restricted. The line going to the canister also felt restricted, but not as much (and I could suck air through it, not gas). The line going to the vent didn't feel blocked at all.

So I first tried to swap the return and vent hoses, but after a few minutes the tank built up pressure and forced fuel out the vent (since the return line goes to the bottom of the tank).

So then I put a T fitting on the hose for the canister line, and connected the vent to that, and capped off the blocked return line to the tank.

So now my fuel pressure is normal, and there are no visible leaks. Please just let me know if I did something horribly wrong by hooking the canister hose and the vent to the same line coming out of the tank.