On my 02 duramax I have to start it with ether but once started it runs perfectly
2002 Silverado 3500 crew cab Dually lt it has a Edge programmer I have put all new fuel lines in it yes I have primed it no didn’t leave it over nightWelcome to DieselPlace
I would steer clear of using starting fluid...
Tell us a little more about your LB7. ( Make, Model and any mods?)
Have you attempted to prime the fuel filter head?
If so, have you primed it and left it over night to see if it leaks down?