Go out to my truck in the morning and she takes along time to start...cranks over but no start..then finally it starts up and the problem is solved for the day, as long as it doesnt sit for too long. Ive noticed that now when I turn the key to the wait to start position I used to hear like a Buzzing sound as if the system is pressurizing..I dont hear that anymore and Im thinking the fuel pump might be bad..Bought a new one just havent installed it yet..Glow plugs appear to be fine and the wait to start light time frame is the same as always. Its the "NON pressurizing sound That I believe is the problem..Just cant figure out why its not doing it anymore...Hopefully ive explained it well enough..But that sound is definitely missing now. 2000 ford F350 7.3 diesel engine.

 

Try plugging it in for a while before you start it first time. If that helps I'd look at GP's or GP relay. The buzzing sound should be the vacuum pump on inner passenger fender.

 

You'll want to put a fuel pressure gauge to know what's going on with the fuel pump. May or may not be bad.

How many miles on the truck? It could be your LPOP draining down while sitting. ???

 

truck only has 112000 on it, but what is loop?