This morning my family was going to church I started the 5.9 Cummins Excursion it fired right up but was running really rough and I had to rev it for the first five seconds to keep it from stalling and after that it ran smooth. We drove about 12 miles made it to church with no other issues. About 2 hrs later after service it started right up and ran fine. About 6 miles down the road we were going 65 and the engine died. I pulled over manually pumped the lift pump until I heard fuel going to the pump. It started right up I got up to highway speed(no decrease in power) drove a mile and it died again. It did this four times. The last time I actually made it 2.5 miles home and it did not die at all. I have had some other issues as of late and they are posted here https://www.dieseltruckresource.com/...d.php?t=162005

Recently I have changed the fuel filter, cleaned the pre filter, and changed the return line.

Could it be my lift pump?

Thanks
John

 

I should also mention that had to push the lift pump button about 60 times before I heard fuel at the injection pump. To me it seems like it could be the lift pump, but I don't want to buy parts it doesn't need. Any input?

John

 

Lift pump or pick up line for fuel either in the tank, or going over the bell housing. I've seen more of the lines going over the bell housing go bad than in the tank, but can't rule that one out either.

 

Thanks vzdude. I don't have the pickup line going over the bellhousing as I used the metal lines that are on the Ford. I removed the tank about 6 months ago and put new lines in the tank. When the lift pumps start to go do they work on and off?

John

 

Can't really say for sure. Usually I just go by pressure, but if your sucking air, then you get low pressure too, so.........Did it have a lower amount of fuel in the tank than usual?

 

Just under half a tank. How do I check the pressure?

 

If I am sucking air would I be able to manually pump fuel with the lift pump?

 

Other than the fact that maybe you are doing it slower than the lobe from the cam that does it while the engine is running? I can't say for sure. Kind of a wierd problem. Need to get a fuel pressure guage so you can watch the lift pressure. Also a clear line between the lift pump and filter housing will show if there are any air bubbles. If you have the aluminum filter housing that drops out the bottom, there should be 2 plugs on the top of the housing , you can thread a guage in there. 1 is pre filter pressure, and the other is post filter pressure. can't remember right off hand which is which. Either way with a recent filter they should be very close anyhow. Thats the two things I would start with. Clear line and guage.

 

No provisions on a 12 valve for checking fuel pressure, you have to make them.
Instructions> https://www.dieseltruckresource.com/...41&postcount=9

If it's stalling I'd lean more towards an injection pump problem. The P pump will suck fuel on it's own and once running won't usually stall. Same goes for air leaks, starting is the problem, not staying running.

 

An other possibility , may be the fuel shut off solenoid , either losing electrical , or the linkage may be out of adjustment - vibration letting it jump to the off position .

 

Hate to hi-jack the thread, but ooops too late!
O.K., it has been brought to my attention, I am wrong again!

Which years had the aluminum housing that the filter canister dropped out the bottom, and there were two plugs in the top to thread a psi guage into? Was it only a year or so on the early 24 valves? I KNOW I have seen it somewhere!

 

Started with the 24 valves. The 12s do have a port on top of the filter mount (actually the bleed screw) that can be used to measure fuel pressure but it's a small metric bolt thread.

 

After the engine stalled I tried to start it by just cranking with the starter, but no go. but after pushing the primer button about 60 times I heard the squeaking by the injection pump cranked the engine and it started right up. Now if the lift pump was working would I have to prime so long to get fuel to the injection pump?

Thanks
John

 

Many parts do not go all at once , they can operate weakly , when I last had some fuel system issues , both the overflow valve I lift pump were working , but weak .

 

I will gather parts and try to get a fuel pressure gauge and see where the fuel pressure pressure is at.

John