So update. The other day I died on the freeway. Found fuel shut off sensor plug not connected my fault. Yesterday truck possibly ran out of diesel and I had to bleed the lines. Finally started. Wife was driving and the fuel gauge isn't correct. But she was at a store and it started for 10 seconds then died. I came and bleed air from fuel lines and she ran like a top all the way home (50miles) today I drove 100 miles and stopped for diesel at 1/2 tank according to fuel gauge. I pumped 8.6 gallons into the rear tank. Front tank isn't there. I fired her up she ran for a few seconds and died. So I began to bleed fuel lines again..I got fuel to most injectors from what I can tell there is alot of fuel from previous day on top of injectors still no luck starting. I sprayed a slight mist of starting fluid into the intake and no results. Batteries are to low again from cranking. But trying to crank after I sprayed the starting fluid seems to found funny in the engine once it's trying to crank. Hard to explain it but like a whom whom whom as the piston goes up and down. Any ideas? I was told the fuel injector pump had been swapped out but I can't confirm that

 

You are sucking air into the fuel system. Check the loop of rubber hose from the lift pump to the frame rail. Once the truck is running, the air will exit via the return line off the fuel filter, but it can be near impossible to start due to that.

As far as the noise goes, it'll probably fix itself once you get it running again; I'm expecting/hoping that it's bleed-down in the lifters; a little slop will cause that sort of noise. Either that, or you've managed to knock a rocker loose, which is far less likely.

 

I figured sucking in air but wasn't sure from where. I'll check more hoses and the line you suggested. Also it didn't start making that noise til I sprayed the starting fluid. It was a mist not hard spray. I don't like starting fluid. But it's not knocking or anything like that just a deeper tone as the Pistons rotates

 

From what I can see the rubber fuel lines are ok but it seems like a weekend job not a Sunday night stuck at gas station look lol.

 

You said the front tank isn't there? Is the fuel selector valve bypassed? They don't always seal air tight so you could be drawing air in there

 

Old farmer trick I learned from prison. Put a little gas on a thick dish rag and put it in air cleaner hole after glow plugs have cycled out. I have been doing this for 20 years. Pull rag quick because it sucks into filter which restricts air. Last 7.3L had 380,000 pressure test 425 psi all 8. Wish I had that motor still. My 88 XLT Lariat F350 has 122,000 on it gas ragged her yesterday glow plug module wasn't firing up three tries no start, gas ragged her to life before batteries died for a night of being stranded.

 

You definitely have air intrusion. Hose cap that tank selector. Go through fuel return . I run 2 clear fuel lines from filter to return system. Then another from injection pump to return system. This will give you visual inspection if air bubbles are larger than 1/16 inch in diameter then you have major air leaks. Fuel doesn't have to show leakage for air to migrate in from fuel leaks. Don't chase ghost.

 

Never never use starting fluid or ether in a diesel that fuel source ignites way too quick. Gas on a rag is soaked and atomizes into mist for slow start anything else will blow a block apart.

 

Update I removed vacuum sensor from fuel filter housing and replaced it with a bolt mine seemed to be broken which I'm assuming I was getting air from there. Primed fuel lines and fired up. Now she runs real rough on idle but is fine under throttle. I don't understand. I let her warm up and drove her hard no issues. But when idle she runs rough. I turned it off and back on and seemed to idle better. I left to go get food in my other car. I came back and tried to start her again. Still runs rough on idle. Suggestions? FYI the vacuum sensor wasn't hooked up to anything before I removed it

 

Any ideas?

 

Um, is it running rough clattery, running rough with no clatter, or what? Any smoke? What color?

 

I'll check smoke in the day time. No clank just seems like a misfire. It's jumpy at idle but drives fine and it goes away under throttle

 

Ok I just started her. No smoke from exhaust. I do smell a bit if diesel fumes. She ran better today. But when I first tried to start her she ran for a second and died. I tried to crank it again she fired up and was bouncing on rpm so I gave light throttle and it stopped. So I still have air getting in from somewhere? She runs fine under load bit idle seems a tad funny since it left me stranded the other night. Any ideas?just a recap what I did is removed the vacuum sensor on the fuel filter housing because it wasn't hooked up to any vacuum line and it seemed cracked so I removed it thinking it was my air intrusion problem. Thanks for all the help sry for late reply wife just had a baby last night

 

I wasn't having these air problems until I replaced the fuel filter and filled it with seafoam. She ran ok off the seafoam until I got fuel the other day and got more air in the fuel system.

 

My personal solution for air intrusion:
Install a check-valve right before the fuel filter, to prevent drain-back.
I use an inline primer bulb(squeeze bulb) for this purpose - they have two check valves, are cheap, and provide a nice way to determine pressure with the engine running and air in the system with it off(you'll hear/feel the air when you squeeze the primer).