Have you commanded full pressure via DVT to see if it would start? Or unplug the fpr?
Yes. Still nothing. It's commanding 6000psi and actual is at 230-300psi.
You need around 2000 psi for injectors to even fire. Your relief valve is likely not fully seated or shimmed wrong. Pull small rubber return hose off fprv to see if fuel comes from there when cranking. Or one of the injectors is returning some serious amount of fuel.
Did u drop a puck while installing the nozzles onto the injectors?