Why does my 1998 Chevy suburban 1500 5.7 liter not start i replaced the fuel pump the relay switch and the fue?

Why does my 1998 Chevy suburban 1500 5.7 liter not start i replaced the fuel pump the relay switch and the fuel filter. When i remove the fuel line from the fuel filter the gas does not shoot out it just dribbles a lot when i turn the key to the on position and when in the off position the fuel gauge goes to half tank and the gas is not getting to the intake.