My 7.3 will start right up after it's been running. Let it sit for more then a couple of hours and it gets real hard to start or won't start unless you give it a small shot of ether. It has new fuel pump, glow plugs and GP controller. Seems like it has to do something with the fuel system anyone have any ideas

 

Have you checked all of the glowplugs with an ohm meter?Also,using ether is a no no on any engine with glow plugs.To check a glow pug set your ohm meter on ohm and see if you have continuity.I don't remember what the spec is but if a plug is bad it will usually not have continuity.I would also make sure you have voltage to ALL of the plugs too.Also I would recommend changing the fuel filter,I always start with the simple stuff first.If both things check out then you have a problem.When I used to get rebuilt pumps(injection) they were never right,most of them that I drove you had to hold the pedal to the floor to start.