Yes, the relief valve releases the pressure when it's greater than the spring tension. The checkvalve referred to at the beginning of this thread is part of the walbro kit, not part of the stock lift pump. This kit has a fuel line from the tank to the injector pump, with a return line plumbed in. The checkvalve is on this return line. You can adjust the spring tension on this checkvalve, and raise the line pressure between the walbro and the inj pump.

With that in mind, I own a 3rd gen, and can't really talk about a stock 2nd gen fuel system.

 

The regulator is post pump. Almost Identical to the GDP kit. It is a 17 psi regulator. Cannot remember the brand though. I bought through a website that was listed in another post. I will have to look into that.

 

my walbro stays at 21psi no matter if its wot or at idle, and it has 1/2 inch lines I had adjust my regulator down from 35psi to 21psi. The hard start problem comes from the ecm set up. If the pump comes on when the key is on then you will have hard start problems but if the pumps comes on when the engine is cranked then you should not have the hard start problem. from my understanding you can have the ecm flashed and reset so the lift pump runs only when the truck does.

 

It is the check valve. I hear the fuel dumping back into the tank. I purchase a spring and shim kit increase my presure a little. I think that I am going to shoot for 20psi.

 

I've got the 25 psi spring in mine, with no shims. It runs anywhere from 26-29 psi. I certainly don't want it any higher.