I have owned a 1990 f-superduty (169,000 miles) for 3 good years and it has started having hard start issues like air was entering somewhere. It would crank/run fine and then not start at all until air was bled out.I decided not to get stranded again until the problem is identified and fixed. I put a return line kit on it and new glow plugs as 2 plugs were bad. Still no start and it seemed to be cranking kinda slow so 2 new batteries and a starter installed. Cranks fast enough now, getting fuel to fuel filter and out of bleeder valve on canister while cranking. While cranking,it has little fuel to some injector lines/none on others. It has voltage to the fuel shut off solenoid, but it is not a definitive "click" but a quiet noise. There is no voltage to the fast idle solenoid. Any ideas or test procedures appreciated.

 

After sitting overnight, pop the fuel filter off and see if it's full or not. If not, you still have air intrusion somewhere.