Hello guys! This is my first time posting so bear with me. ENGINE SERIAL #44407550 - I have a 2010 caterpillar 4.4L that is kicking my butt. Engine is in a brush bandit 250xp woodchipper. The engine currently is a crank no start. I have no codes. Engine WILL run on starter fluid, so I know my base engine is good. I have some sort of fuel problem. I have the common rail system, with a 320d injection pump. I have replaced both fuel filters. My low side fuel pressure, while cranking is 10 PSI (it should be 50-70psi). My low side pressure is leaking passed my fuel metering valve (solenoid on top of injection pump). I know this, because I pulled the fuel return line off the injection pump and while cranking, watched fuel come out of the port. If I block off the fuel return line port, on my injection pump (Dead head my low side pump). MY low side fuel pressure jumps up to 60psi. I have replaced my fuel metering valve (solenoid only), but the concern is still present. I LOAD tested the metering valve circuits (both test good). I found I am getting a pulsed ground signal from the ecm while cranking (I believe is normal) but on the power side I am only getting 1-1.2V with key on or cranking. I though i might have another sensor pulling the voltage down so i unplugged EOP, MAP, ECT, FRP and both timing sensor, one at a time but is still only have 1-1.2V. I pulled the metering valve off and plugged it into the harness and I am not getting any movement. Based on this I replaced the ECM and had cat flash it. My concern is still present. I have checked my pressure relief valve (attached to my fuel rail) no fuel coming out. I don't understand why my pressure jumps up to where it should be when I block the return port. I feel like I should have movement and more than 1.2v going to the metering valve. maybe a weak low side pump? I am at my wits/wallets end with this thing. Any help would be appreciated. I have attached pictures of the metering valve and injection pump Thank you.
Theory
Need to get Cat ET hooked to this unit and check the fuel rail pressure actual vs desired. Very common to have fuel injectors dumping rail pressure on these engines.
If I'm not mistaken that fuel pump has to be timed. There is a procedure for locking it before removal.
If you decide to check the injectors here is the procedure for your engine.
Yup.. injector return to hi..
Desiring 6000psi, actual Frp is at 120psi
Follow this troubleshooting procedure, it will likely lead you to the one I posted earlier.
Did you ever figure it out ?