Have you checked to see if the fuel shut down solenoid is working correctly?
If it's shaft retracts when the key it turned on you have power to the solenoid and the ECM is probably ok.
Fuel filter and priming is usually an inexpensive routine fix as Gary suggests.
Just had the same problem on my diesel generator on Friday. The fix was to disconnect and reconnect the fuel solenoid wire connector.
But, I changed the fuel filter first, to no joy.
1995 CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs