2001 duramax, it will start right up in the morning, run for 2 or 3 seconds and die, pump the primer about 10 times, fires right up and will run all day with no problems at all, next morning same thing, i have changed the fuel filter HELP
Have you checked anything in other words did what has been suggested?
1) Take off the OEM filter
2) Clean and inspect O'rings (both)
3) Inspect housing and water sensor for cracks.
4) Put lil Vaseline on the O'rings and reassembly make sure everything is tight.
See what happens. It has to be a loose of prime issue or it would seem as you said priming it solves the problem.