Diesel Bombers - 05 F 250 Harley Davidson diesel

I'm having a problem with the high pressure oil bleeding down overnight. It takes about 8 to 10 second of cranking the first time you start the truck for the day. It will start perfect the rest of the day until it sits overnight again. I have replaced the high pressure oil pump, injectors are 190s,from inavative, EGR delete, head studs,I have a fuel system from inavative, PowerMax turbo, aftermarket FICM, and programming from innovative. I've replaced the timing cover the high pressure oil pump the regulator it doesn't matter if the truck is warm or cold if it sits for about 15 hours it loses enough pressure where it has to crank to build pressure to start. Other than that the truck runs perfect lots of power lot of fun just doesn't want to start as quick as it should after it sits for a while. It always starts strong when it starts not like it is hard to start just takes a lot of cranking. Has anyone else experienced this and what is the cure please help!