my 2003 common rail takes too long to start, ive compared it to other trucks of the same era and its about 2-3 times as long as it should be, the longer the truck sits (over 4 days) the harder it is to start (15-20 seconds of cranking) it does it when the engine is hot and when it is cold, aswell as when the air tempature is hot or cold, i have tried cycling the key 3 or 4 times to try and build fuel pressure but it does the same thing. i can run the truck, turn it off and immedietly crank it over again and it takes just as long.
i have replaced the starter, both batteries, flow tested all the injectors and they are good, and replaced the check valve on the top of the rail coming from the high pressure pump

has anyone seen this before or have any ideas of what could be happening? ive heard maybe a crank position sensor or a cam position sensor?

 

check the fuel pump and fuel filter. had a buddy with the same problem, he cleaned out his filter housing and put in a new filter with injecrtor cleaner and it made it start 10x better

 

What's rail pressure when you are cranking?