I have been having some major trouble with this truck after replacing the fuel pickup screen in the front tank (which was rotted off and in many pieces in the tank) with a piece of fuel line. Now It will not start and has air still coming out of the schrader valve, even though there is several gallons of fuel in the tank. I have opened the injector lines to try and bleed the air out, and repeatedly poked the schrader valve to let the air out, but it still has air in the system. I figured that the air got in there when I dropped the tank and had to unhook the fuel lines. However, when i went to start it the other day, just after getting the fuel tank back in it, it started right up and ran for 30 minutes or so with no problem. But today, It won't start (except with ether) and I even tried switching to the rear tank but it still has air in the system. I know that the fuel line I installed in the front tank is long enough because when installing it, I pulled it out several times to try and get the length right, and saw that it had been in the fuel because it was wet with diesel fuel each time. And the piece of fuel line is cut at an angle on both sides as to not suck to the bottom of the tank.

 

they key piece of info is here:
if she starts on starting fluid and continues to run,then it's getting fuel.the problem is with the glow plug system.

 

hat he said x2 you bumped something under the hood now you have no glows...

 

my guess is you disturbed something in the fuel lines and it is now sucking air.
or you have a bad lift pump sucking air.
try disconnecting the fuel line going into the lift pump and hooking it up to an external fuel source like a portable boat tank. if it still pushes air, it is the lift pump.
if it runs fine like this, it is in the lines.
then start working your way back to the tanks with the external tank.
sooner or later you will find the problem spot.