Fuel pump / starting issue.
I get in the truck in the AM, and hit the key for glow plug warm up procedure...and the fuel pump comes on and hums for the allotted time like always...but it will not fire when I hit the key. So I cycle the key 10 times, hitting the starter now and then...white smoke comes out the tailpipe...and then, with a very audible "click" the pump will draw down and then the truck starts instantly. After that, it starts... no issue. But if I leave it for say, 6 hours, it cranks a while then starts...
I'd say I have a leak in the system letting the fuel drain down...but it builds pressure and starts instantly AFTER I hear the "click" under the hood..or at least it sounds like it's under the hood.
This has been going on since the day I changed the filter after running out of fuel..