1990 blazer 350 5.7

Hi I got a 1990 blazer k5 4×4 5.7 350 full size blazer that I’m having problems with the injectors wont inject they wont spray first we thought it was the fuel pump and fuel filter but it wasn’t it or the computer it ain’t none of that. the strangest thing is if I get a piece of wire and wire it to the injectors to place it to ground the injectors will start working they will spray a lot but it get flooded so we bought a new computer it still the injectors wont work they wont spray. I’m out of ideas please help