Is it toggle switch controlled or stock lift pump wiring? Have you bled system all the way to rail and return line as described? You obviously have skills, one line answers don't tell me much. Just trying to help.

 

I have fuel coming out the supply to the cp3 I can't get fuel out of the cp3 if I could get that it would be no problem but not getting fuel out of the cp3 I won't get fuel out of the return

 

I have fuel coming out the supply to the cp3 I can't get fuel out of the cp3 if I could get that it would be no problem but not getting fuel out of the cp3 I won't get fuel out of the return

 

Man, you are describing a classic air lock problem. Please don't be insulted by my remarks. The return line is there for what fuel doesn't go thru rail. The pump itself is air locked and the rail also. The return line banjo on pump will bleed the air out of the pump and loosening the injector lines at rail will bleed the rail, try it please. VP44, P pumps, VE pumps all had to do the same procedure. Even individual pumping units such as 2 cylinder Lister Petter engines had to be bled at injectors to get started. I worked for Cummins for 14 yrs and had my own shop for 15 yrs where we rebuilt 15-20 CR engines and replaced 5 or 6 Dmax CP3s because they don't use a lift pump stock and the CP3 overheats, destroys themselves. It's only a little time wasted and everything is easy access if I'm wrong and I will apologize to you. The reason I asked about injector replacement is maybe the injector cross tube retaining nuts need retorqued. ??? It might be just the rail that is air locked since it already has been run. If the pump was faulty or broken, then you wouldn't get fuel out of pump return.

 

So your saying just loosen the return banjo on the cp3 and the injector lines and keep turning the engine over to bleed out like older models? Because I took the supply line from the cp3 to the rail off and no matter how long I crank I get nothing by the way I appreciate the help

 

Yes, but just 1 at a time. Return line first, and if still nothing, stop there. Need to verify you have lift pump pressure while cranking. I checked out Air Dog's web site and they do use PCM commands to actuate relay for power to LP. I'm thinking since you got more air in lines than ever, it all ended up in CP3 and rail at about the time it went rough idle on you. But that was for newest Air Dog kits, if yours is an older kit that runs off of ignition run circuit, it wont run while cranking. Check it out.

 

First thing to check is if it will fire and run with starting fluid of some type. If it will start and run you have a leak somewhere, if not then back to checking fuel supply.

The CP-3, injectors, and rail are self air bleeding. They simply cannot air lock due to the design. If you have fuel delivery to the CP-3 inlet constantly while cranking and nothing is coming out to the rail it could be FCA or even the COV stuck wide open. Check your CP-3 return line when cranking for fuel flow to see if it actually getting fuel thru the CP-3.

 

Well guys after coming to the conclusion there was something messed up inside the pump I pulled it and took it back to the shop I had gotten it from they spun it and found out there was something up inside the gear pump so now once I get this new one in we will be back in business thanks for the help once again guys!