Hooray... I got it started. I gave it a small shot of ether(a no-no, but I was desperate), gave 1/4 pedal and kept cranking until it was clearly running. Hope I did not ruin something else. NOW I AM AFRAID TO SHUT IT OFF.

Patdaly, It takes four or five pumps to slightly hear the air leaking noise and it gets louder if I do more pumping..say 10 times.

Should I be looking for an air leak?

 

Only way to tell is when you shut it off try and restart it after she runs smooth.

You probably just had to bleed it out good, only one way to tell........

 

OK I shut it off and it starts back up with no problem. I will let it sit awhile and try to start it again. What could cause this to happen so suddenly and should I be trying to find a potential air leak?

 

My guess is you will find some period of time where you do lose prime. If it rolls over and doesn't catch with 1/4 throttle right away, pop the hood and prime it with the lift pump and see how many strokes it takes. You are actually one of the longer lived fuel hose setups if it is all factory, they tend to crack and admit air up by the engine, or the steel lines out of the tank module tend to rust thru and admit air.

But lets not get ahead of ourselves, if it is, the fix is relatively cheap, but us usually a dirty filthy job.

 

Thanks for all your help. Regarding the fuel hose setups they are all still original factory parts. I will do as you say and monitor it.

Would it make sense to do a pressure test and if so can it be done on the entire fuel line from the fuel tank to IP. Or must the individual components and lines be tested separately?

 

Typically, not always, if you prime to start to get the air out, the leak is at the higher level from the ground than the tank. That being the lines to the engine from the steel on the body or around the lift pump, or the fuel heater. I know Infidel has a procedure where he pressurizes the fuel tank (less than 2 psi IIRC) and look for leaks on the lines after you have cleaned them off.

I've replaced my rubber lines to the engine a number of times and they looked fine except for very fine cracks but still let in air.

 

You can check for fuel system leaks by pressurizing the tank through the fill cap, 10 psi max.
An air blow gun wrapped in a rag works to pressurize but then you need another person to go hunting for any leaks.
I use an old fuel cap drilled and tapped with an air hose fitting to make it a one man job.
Also comes in handy for fuel filter changes. With the bleed screw on top of the filter cracked open and the tank pressurized I can fill the new filter and bleed all the air out in about 15 seconds.
I haven't used a primer button in 15 years.

 

This pressure is the same reason air leaks happen. As the fuel tank cools, it creates a vacuum and any air leak will let in bubbles to the system. There is supposed to be a vent, but I know when I open the cap it still huffs when I fuel up.

 

The tank is supposed to be vented at 3 psi pressure or vacuum.
It should make a hiss when you open the cap.
Air gets into the fuel system when there is a leak for the same reason a straw no longer holds water when you take your finger off the end.

 

You got some good advice from the others regarding testing.

Anymore if I have a problem I don't even bother testing, I just blow new lines all the way from the tank to the engine, Diesel rated rubber works just fine. The only thing you have to check then is to make sure the module lines aren't rotted out.

I chased leaks, fixed them only to have the other stupid line ( or the same line further back ) mess up, and usually when it was bloody -10 degrees outside.

Life became simple once I adopted infidels strategy of rubber all the way back.

 

Pressurize the tank like Infidel said........I'm guessing you may have a leak at the fuel heater gasket interface. If you have one of these the best recommendation is to delete the fuel heater; useless and troublesome at best. Hope whoever is driving it now at least checks the oil when they add fuel.

Also, the fuel return line behind the P7100 is prone to cracking and dropping the fuel prime.

 

3 psi vacuum is a pretty good draw, like 6" Hg so ya, that would find any air leaks and amplify them. I know I think the spigot for my ESPAR on the tank must have a pin hole in it somewhere right at the mount or in the tank. I get air in that system if it chills overnight after a long trip to heat the tank.

 

Thanks For All The Great Feedback. Based on your advice I made the assumption that it is an air leak (also noticed that the lines from the tank were quite rusted) so because I was able to get it started (thanks to your help) I brought it to the mechanic to repair/replace.

He tested for leaks and found the fuel pump was leaking. we decided to change the lines as well. He dropped the tank and inspected everything inside which was in good shape. So now it starts right up.

PS - What I did not mentioned in my initial post was, prior to this problem of not starting at all, that when I let it sit overnight and then start the truck it would blow alot of white smoke for several minutes. Also the longer it sat the more times it took to start before it stayed idling. The mechanic said that an air leak will cause the timing to retard and create that smoke.
I am mentioning this so that if anyone reading this post in the future may benefit from this advice as well as everything else provided by you guys.

THSNKS FOR ALL YOUR HELP

 

Glad you got it fixed but I don't know I'd ever let that mechanic adjust your timing which is only changed by moving a gear on a shaft then torquing a nut down.

 

The mechanic is correct. The air bubbles in the system act as springs and when the injection pump tries to reach the pop pressure of the injector, it takes longer to compress the air in the fuel than it would to just compress the fluid.