Have a LMM we just finished head gaskets on. I don't know if I am just tired and over looking something or what. Truck will crank but won't start. only codes are IAT and Coolant temp sensor. Truck shows 5700ish psi of desired rail while cranking and only 71psi actual. Actual PSI does not fluctuate at all, stays steady at 71PSI. I unplugged the FPR thinking desired would shoot up to 26,500 PSI and it didn't. Rail pressure stayed the same on desired and actual even with FPR unplugged. I ran a hose from a fresh can of diesel straight to the line going to the CP3 to rule out any issues with the filter head or with the lines going in to the fuel tank. Still no start. Any ideas are greatly appreciated!