I'll share some of my experiences trying to start a year-long sitting 7.3 I'd just bought, since it was an ordeal getting adequate fuel to the injectors. It had been parked by PO for not starting.
Cranking to purge air would not yield more than dribbles at the caps. I'd filled the filter with diesel/stanadyne fuel treatment, put in a e-lift pump, and plumbed it up to a small tank of fresh fuel. It'd fire hose the stuff out the other side of the filter.
I'd removed and plugged the return line to the filter, rerouting the IP's return to the 1 and 2 injector returns with a 't'. I used a vacuum mighty-vac hand pump to pull fuel thru the return of the IP and plugged it back in return lines. Fuel was plentiful but it would not fuel injectors sufficient to do more than dribble and bubble, make any smoke or chug even with ether.
I cleaned everthing around it and pulled the IP housing cap off and moved the fuel metering valve linkage at the bottom with a clean hooked scribe. I tapped on things with the wooden end of the hammer. I filled the IP with Stanadyne fuel conditioner stuff, tapped some more and put the cap back on (making sure the the shut-off is hooked in there just right), and cranked. Killed batteries yet a gain and put them back on charge.
After a time I went back at it and cracked open every one of the injector lines again and cranked. Still not ******* out fuel at the caps. Charge batteries, repeat. I begin to see ****** looking diesel ******* out from lines at injector caps on the ones that'd hadn't been dribbleing much fuel. Recharge batteries; repeat. A little more fuel seems to be coming out. I close the ones with the most fuel, cranking now I might have had a puff. But nowhere near lively.
Batteries charging I meet my colleague at the walking distance pub to commiserate. after a few beers and a bite (and the waitresses saying my saving grace in her rental truck was too old for me), grabbed the batteries, hefty cables and connected the two together after finding where to hook them on the rental. She liked to spin fast. Fast seemed to make the difference.
Did a little bleeding, closed em up and shot some ether down her throat. Low and behold she chugged to life. Said farewells and went about trying to make her road worthy for the 300mile trip to get her home since after that first start there was no stopping her.