Before trying to start, disconnect the electrical connection from the FCA, it is the only electrical connection on your CP3 injection pump. Just squeeze the tab to release and pull, it will come apart.
Now try and start, if it starts you have a low rail pressure condition, by disconnecting the FCA, you have fooled the ECM into believing you have adequate rail pressure. The ECM needs to see a minimum of 3. 5k rail pressure to fire the injector solenoids, by disconnecting the FCA, it by default raises your rail pressure to max pressure. After it starts, if it does, shut it down, you do not want to operate it with the FCA disconnected.
Now you have to figure out why you have low rail pressure, faulty COV, PRV, RP Sensor, Loose cross tubes, bad injector(s) to name a few. I will add a link that will give you a better understanding than my rambling, but the first thing I would do, would be to re-torque the cross tubes. When the engine is cold the tolerance between the cross tube and injector is greater than when warm, thereby allowing more fuel to bypass and lowering rail pressure, when the engine is warm the fuel is thinner, so that could also bypass more fuel, kind of a double edged sword. Jess
Here's the link;
Dodge Cummins diesel diagnostic repair and diagnostic information for Dodge diesel pick-up trucks courtesy of Oregon Fuel Injection