1999 Dodge Ram 2500 Dodge with 5.9 Cummins won't fire.

I started my truck the other morning and it ran for about 5-7 seconds it ran fine and then shut off. I proceeded to try and start it again and it would crank but won't fire. That night I replaced the fuel filter on it. I also loosened the banjo bolt between the fuel filter and the injector pump to insure that the pump was getting fuel. The truck still wouldn't fire. I can hear the fuel pump pumping fuel, so it is working. At this point I don't know if it is some kind of sensor in the computor or possibly an electrical/solenoid problem. I am going to put an OBD unit on it tonight to see if error codes come up. Any help or troubleshooting would be great. Thank you.