Correct me if I am wrong, but unplugging the CP3 forces it to deliver max flow at max pressure irregardless of anything else. In other words it bypasses any erroneous signals that the computer may throw at it.
So if the CP3 is working at max and the pressure relief valve is not allowing any diesel to pass, then all things being equal, there should be pressure at the injectors. Fuel press at the injectors = engine running.
BTW, I am presuming that all the lines and pressure rail have been primed and are full of diesel and not air. Also presuming that there are no new codes.

If the above does not produce good fuel pressure when a line is cracked at the injector, then there are other problems. As has been stated previously, make sure that the lift pump is supplying fuel at a good rate and pressure right at the pump when the key is turned on but without cranking the engine.
You do have a clean fuel filter don't you?
Consider this a stupid question, but do you have fuel in the tank? Like at least 1/4 of a tank?
One thing you can try. Open the drain valve on the bottom of the fuel filter and take note of the volume of fuel that runs out. With the valve still open, have someone turn the key on and see if the rate of flow changes. It should now gush out and make a nice mess on the floor.

If the lift pump is suppling fuel at any kind of pressure and at a good flow, then just maybe you have a bad injector pump. If you installed a NEW fuel pump, chances are that it was not bench tested. A reconditioned pump has a better chance of being pressure tested prior to shipping.

 

If I understand this correctly, with the key in the run position (not cranking), you had voltage at #2 injector or 2 of the injectors? And then you cranked it over and after you stopped cranking a different injector had voltage, correct?

If that is correct, I don't see where you have tested for voltage "as" someone is cranking over the motor. You haven't mentioned the age or condition of the batteries in your >5 year old truck. They may be strong enough to turn over the motor, but not have enough voltage to run the computer which is what fires off the injectors. After cranking, the voltage recovers.

Test your voltage at the battery while cranking. Check all your battery connections for cleanliness. Check your cables for internal corrosion.
Back to morning beverages. . .

 

I am going to take the truck to real diesel shop and have them figure it out. that way I can find out which injectors are bad.
the shop is the on I bought the pump through they heard that what happened and going to give me a hand getting it figured out.

 

as in not the shop I first went too. keep you posted

 

well it was 4 bad injectors. 800 psi on rail at start up. a gallon evey 20 seconds at return line. apparently 03 had bad injectors from the get go. as you all said. so I am buying 6 new ones. that hurt the wallet but it is going to help. oh buy the way rail pressure is 23,000. I was told not to crack lines while running . I would lose fingers. at lest that is what the shop told me.

 

So how did they determine that you had 4 bad injectors? Check voltage?

 

should have done a flow test to check them

 

the voltage is fine on injectors. with the return line off and filling a gallon container in 20 seconds just cranking not running and only 800 psi at cranking. and blocking lines off. thry said that injector 1,3,4,6 were bad 2 is starting to leak 5 ok. that in a nut shell is why I can't get a start out of it. also had batteries check and were good.

 

well got injectors in and stats fine.