Today I just put a new cp3 pump in and after cycling the key a few times it fired right up I let it run a little while in the shop and took it for a drive about a half mile and it starts to run really rough and won't start after I shut it off did some investigating and found that I'm getting fuel to the cp3 but nothing out so I'm guessing the cp3 is junk? Or would there be a reason for this?

 

Could it be pump was not problem in 1st place? Did new pump come with regulator? What prompted pump change?

 

Yes pump came with a new fca the pump was changed due to only building 7000 psi at wot

 

Low rail could be to multitude of things. Bad relief valve, faulty rail PSI sensor, and most likely, injectors themselves or transfer tubes in head not torqued to spec. Have injectors been out or replaced?

 

Yes injectors were replaced about 8 months ago but what I'm trying to say is that I have fuel going into the cp3 supply and nothing coming out while cranking

 

Unplug the FCA See what it does! Did you torque the nut down on the CP3 gear?

 

Yes I torqued it

 

What kind of lift pump? Stock, in tank?

 

Man, I've been talking to a guy with a Dmax with same circumstances. If you bump the starter, the PCM picks up the no start and will run the lift pump for 45 seconds. Have you gotten the air bled out by loosening the banjo bolts? I know you drove it a little and went rough idle on you, but between fuel draining back while pump was replaced and the air in injection pump from supplier, it's gotta still be bled. If lift pump is working, keep bumping the starter and wait till you have solid stream out of return line banjo. The FCA is a normally open valve I believe so fuel should pass thru and you can bleed rail by disconnecting fuel lines at rail. Set up an old fuel cap for an air fitting with a regulator set no higher than 10-15 psi. Back to basics.

 

The lift pump is an airdog 150