320psi rail pressure

[Mpsoldier]

little lost right now. i have 320 to 340 cranking rail pressure. The truck was running fine and was holding 22kpsi when i went to splice in my lift pump truck wont start. Even with positive pressure on the system.I dont have a fuel filter under the hood and the fuel system was simplified down to 1/2 line directly to cp3. cranked injector lines there is fuel there at the end of both rails. any suggestions. btw fpr is unplugged and return rates are good.

 

[$chultz38]

Air in the rails somewhere. The ECM isn't seeing enough psi to fire the injectors.

 

[Mpsoldier]

yeah just seeing if there is any other tricks to priming these trucks.

 

[THEFERMANATOR]

Air in the rails somewhere. The ECM isn't seeing enough psi to fire the injectors.

No, there isn't enough rail pressure for the injectors to pop. You need at least 1200 before the injector can even open.

To the OP, are you sure you didn't get a piece of debris into the system and plug the FCA?

 

[Mpsoldier]

No, there isn't enough rail pressure for the injectors to pop. You need at least 1200 before the injector can even open.

To the OP, are you sure you didn't get a piece of debris into the system and plug the FCA?

there's always a possibility, at this point i mine as well change it out i have couple more in the shop.

 

[$chultz38]

there's always a possibility, at this point i mine as well change it out i have couple more in the shop.

Unhook the return line going back to the tank on the drivers side vavle cover and see if you are returning fuel with the pump running. Can't be plugged if you do

 

[Mpsoldier]

Any other suggestions raining all day and of course moved the truck outside when it was running. Afraid to melt in the rain by sitting on the tractor and push it back in to work on it lol.

 

[$chultz38]

If you are returning fuel to the tank then you need to bleed the air out out the rails.

 

[Mpsoldier]

If you are returning fuel to the tank then you need to bleed the air out out the rails.

going to check return again in the morning see what happens. If nothing i will pull fprv clean it and then check again for return.

 

[nwodiesel]

If you are returning fuel to the tank then you need to bleed the air out out the rails.

don't mean to poach the post in any way but Im putting mine back together with new injectors tomorrow and wondering am I gonna have to bleed my rails as well? thanx

 

[$chultz38]

Most times no you don't. Just crank it over after pumping the hand pump on the filter head like a teenage boy in the shower. It won't start right off you'll have to keep pumping it up until it gets hard to pump crank and repeat.

 

[Mpsoldier]

so i am getting fuel out the return but not much after about say 2 sets of 10 second cranks i am getting about 1" in a coffee cut. i am supplying plenty of fuel.

 

[$chultz38]

Still have air in the rails or bad rail pressure sensor maybe?