I have had my 04 cummins in 2 shops and 2 dealerships and none of them can figure out why it wont start. so far have replaced injectors, injector pump twice, booster pump in the fuel tank. the only thing that will make it start is to take the fuel filter out, put it back in and it will start once. any ideas. when it starts it runs great good milage and pulls awesome

 

Welcome to the forum, Someone will chime in with info on it.

 

Not being a smarta$$...but did you change the fuel filter?? Because if taking out the filter and putting it back in is what makes it run I'd say you got a junker of a filter that's somehow restricting flow and won't give your engine fuel after the initial start. I had something similar happen on a 12v a couple years ago and it ended up that the internals of the filter were damaged when the canister was crimped at the factory. Good luck.

 

I hate to say it but your CP3 may be shot. you could have gotten some trash into the low pressure pump side of the CP3 and that might have chewed up the gears causeing you to loose pressure.

I would chack the inlet to the CP3 and make sure it isnt blocked first.