Have a 03 2500 Cummins. Had the truck tested for long long start. The mechanic said the return rate was 3 times the rate and said new injectors. Drove it home and let it sit a few months. Got some injectors with 20k on them. Replaced rings copper washers all 3 times they have been removed (because crank NO start). These parts came from cummins. Truck turns over and white smokes from tail pipe but no start. It will run on spray... I know bad idea, but just wanted to see. We we ran it on spray it started puking fuel from the exaust pipe. ... lots of raw fuel. Totally at a loss on this. HELP!

 

Sounds like you have a injector stuck open.
I would pull all injectors and have them tested.
When you put them back in, did you torque them to spec ?