2001 galant 6g72 losing prime

My 2001 galant with the 6g72 is losing prime after it sits. I have to crank and crank till it finally chokes into start. After it runs it will start right back up. But after it sits over night it loses fuel prime again. And ideas. Help appreciated thank you. Replaced plugs and cap, replaced fuel pump. At one point wire to injector ground out on a bolt and fried ecu fixed all that. I feel maybe its a injector or regulator but im hoping someone has been where i am .

There's a valve in the fuel pump assembly that's suppose to keep the fuel in the lines when off. More than likely that valve is bad and allowing the fuel to return into the tank.