D3B Running Sporadically

[RossEagar]

I've got a D3B LGP (24Y) that runs fine for the first 10-15 minutes of pushing at full throttle, but then acts like it's starving for fuel and starts running real rough. It usually shuts down and I have to let it sit for 20-30 minutes. It takes a bit of cranking, but eventually starts back up and everything is good for another 10-15 minutes. I've replaced the fuel filter, cleaned out the screen in the lift pump, and even had the pressure pump and lift pump rebuilt. Thinking I might have some rust in the tank, I even bypassed the smaller fuel line with a 3/8" tube coming straight from the drain value on the tank to the lift pump. I've blown through all the lines and made sure the air filters are clean as well. Nothing has really changed, though, so I'm not sure where to look next.

Any ideas on what I'm missing? Are there any more screens in the lines someplace?

Appreciate any help!

 

[shopguy]

You are talking about the screen in the fitting between the supply line and the lift pump?

 

[pittsburgh cat man]

Hate to say it but are the valves in bottom of tank plugged ??

 

[RossEagar]

You are talking about the screen in the fitting between the supply line and the lift pump?

Yes, correct. Is there another screen I’m missing?

 

[LCA078]

Is your tank vent hole open? Try to run without fuel cap, or at least pretty loose, to see if you have a vacuum issue.

 

[RossEagar]

Hate to say it but are the valves in bottom of tank plugged ??

I was thinking that as well, so that’s why I bypassed the original line and came off the bigger drain plug. I made sure it has the screen sticking up in the tank to keep any rust from plugging it up. I’ve got plenty of fuel at the lift pump now.

 

[RossEagar]

Is your tank vent hole open? Try to run without fuel cap, or at least pretty loose, to see if you have a vacuum issue.

I checked it today and it was open. Haven’t tried to run it without the cap, but I will tomorrow to see if it makes a difference.

 

[IDwaddie]

Your problem sounds like a restricted fuel supply because it runs and starts, idles, but won't run continuously at high power. When you shutdown, the line slowly refills and you repeat the cycle. Some trash can be moving around on the tank bottom intermittently covering the fuel outlet.

Immediately after it stops, remove the supply line to the injector pump at the pump. If you have fuel gushing out there, then the problem is in the pump. If you don't have fuel gushing out of the line, the problem is somewhere between the injector pump (IP) and the fuel tank. Pinched line, clogged fuel tank vent, crud in the line etc. Try blowing back with compressed air through the line. You may have to blow from the IP to the lift pump and then from the lift pump to the tank separately depending on how the system is plumbed. Look for a screen on the lift pump.
Diesel powered farm tractor commonly have this problem but I am not that familiar with dozer fuel systems.
Good luck!

 

[pittsburgh cat man]

Some questions for you did you have rust in screen when you cleaned it? Have you checked it again? I drove a lot of miles one time to check one doing the same thing did the filter change cleaned the screen stayed with machine for a hour after I got it running never missed a beat while i was there stinking thing quit before i made it back to shop. It had a rusty tank.

 

[Dave Neubert]

I would not run it off of the drain line asking for trouble hook up a fuel pressure gauge and see if pressure drops or is low to begin With

 

[shopguy]

Should be a capped off tee in the line at the filter base for the gauge