kubota d1105 looses prime running

1mouse3

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I am dealing with a kubota d1105 that is losing prime running and exhausted all paths I can think of past replacing the IP. I started by replacing both the feed and return line along with both filters, this solved nothing. So I pulled the mechanical lift pump, there was no sign of leaking into the crank case and pumps up fuel fine to the main filter. After casing my tail some, I replaced all clamps with ones that would get tight such that cant twist them on the fittings. Seeing nothing so far, I pull the draw line back out the tank to check the somewhat new pick up and was not clogged. Not seeing nothing wrong with the feed, I went chasing the black smoke issue and that was not the source. It involved pulling the injectors and pop testing them to find one that was low with a slight dribble, so was replaced it. So the the black smoke is solved and only hint of blue here and there. With this issue not making sense by now, I put a electric lift pump on to rule out a wore out lobe for the other pump. This primes the system up easier but air is still replaceing the fuel in the main filter. Where do I go next with finding the source of the problem?
 
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robdean

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I am working on chasing your same issue. I am starting at the black smoke also since i know thats an injector.

What product did you use to pop test it?

What was the fitting thread and size for the injector to pop test it?

I will keep you posted on what i find when its related to your issues to see if we can get them going.
 

Rdnck84_03

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Have you checked the fuel return line to the tank? Didn't see where you said anything about checking it? If plugged could possibly be dead heading pump and pushing air in the return lines back to the filter.

James
 

1mouse3

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Have you checked the fuel return line to the tank? Didn't see where you said anything about checking it? If plugged could possibly be dead heading pump and pushing air in the return lines back to the filter.

The reurn line is new along with its hose that drops into the tank. When line was unhooked dealing with the injectors, it was self siphoning fuel from the tank. I will recheck the line off the IP and see if has a removable fitting I can check.

I am working on chasing your same issue. I am starting at the black smoke also since i know thats an injector.

What product did you use to pop test it?

What was the fitting thread and size for the injector to pop test it?

I will keep you posted on what i find when its related to your issues to see if we can get them going.

This is the one I got and it has the right fitting on one the two lines it comes with.

pop-tester
 

Rdnck84_03

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The reurn line is new along with its hose that drops into the tank. When line was unhooked dealing with the injectors, it was self siphoning fuel from the tank. I will recheck the line off the IP and see if has a removable fitting I can check.
With everything you have already tried doesn't leave much that makes sense. Does the fuel feed from tank come out of the bottom or a pickup from top?

If it is a pickup tube I would think about the only option left is a crack in the pickup tube that starts opening up from engine vibration when it starts.

Have you tried feeding fuel from a can instead of fuel tank?

I wouldn't think the injector pump could put air into the system unless it was fed air. I have a tractor that the ip leaks so bad that it will drain the 10 gallon fuel tank in a week if I park it facing down hill. Have to crack the injector lines to get it started if it sits more than a couple days, but otherwise still runs good.

James
 

1mouse3

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With everything you have already tried doesn't leave much that makes sense. Does the fuel feed from tank come out of the bottom or a pickup from top?

If it is a pickup tube I would think about the only option left is a crack in the pickup tube that starts opening up from engine vibration when it starts.

Have you tried feeding fuel from a can instead of fuel tank?


This is on a ditch witch mini skid and the tank is on the side, they made the tank hard to remove. On the top side there is two rubber plugs, a brass fitting is popped in to it. Rubber hose gose on both side, in tank side they broke off and fell to the bottom. For the feed hose I used one of these for pick and weight to keep the hose at the bottom, found a 5/16 one tho. No I have not tried another fuel source.

pickup
 

Rdnck84_03

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This is on a ditch witch mini skid and the tank is on the side, they made the tank hard to remove. On the top side there is two rubber plugs, a brass fitting is popped in to it. Rubber hose gose on both side, in tank side they broke off and fell to the bottom. For the feed hose I used one of these for pick and weight to keep the hose at the bottom, found a 5/16 one tho. No I have not tried another fuel source.

pickup
You definitely have a head scratcher there. I think i would run into a fuel can with just the feed line, leaving the return in the main tank.

Just a random idea, how far is the return line insert into the tank? Is there any way the air sent to the tank from the return could be close to the pickup line and sucked up?

James
 

1mouse3

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Just a random idea, how far is the return line insert into the tank? Is there any way the air sent to the tank from the return could be close to the pickup line and sucked up?


The was no return line left attached when I fixed the feed line in the tank, it was ran for some time like that with no issue, then it sat for close to a year and found it doing this. I dont have the return hose I just added all the way to the bottom, but far enough it will be submerged in the fuel. The feed line has enough slack that the pick will hang out on the bottom.
 

Rdnck84_03

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After studying a fuel line diagram for that engine the only place for air to get in the filter is the feed line. So there has to be either an intrusion point somewhere between the filter and tank, or the return is aerating the fuel.

Could try pulling the return line running to the tank and get a hose long enough to run to a catch can. This would rule out the return aerating the fuel.

James
 

1mouse3

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After studying a fuel line diagram for that engine the only place for air to get in the filter is the feed line. So there has to be either an intrusion point somewhere between the filter and tank, or the return is aerating the fuel.

Could try pulling the return line running to the tank and get a hose long enough to run to a catch can. This would rule out the return aerating the fuel.

I will try running the feed from a fuel can sunday and see what that dose.
 

1mouse3

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I had it run for a bit off a fuel can, and it still died but ran for a fair bit. So I cut up the pre fillter to see what was insited if any thing. It looks like some rusty sand is collecting in there, but is a plastic tank. So guess will need to pull the tank to find out what is in it. Will have a new filter tomorrow and will try again.



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1mouse3

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It ran today with the new filter till the hose in the fuel can was barely in the fuel. So guess need to pull this tank to find out what is in this tank.
 

snicklas

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It ran today with the new filter till the hose in the fuel can was barely in the fuel. So guess need to pull this tank to find out what is in this tank.

Algae? You did mention it had sat for a time. Tank being plastic, that is the only “easy” way I can think of to get a sandy/rusty stuff in the fuel……. or there is and opening somewhere that is letting stuff in the tank that is hidden by the machine……
 

Rdnck84_03

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Wonder if it could be pieces of the the old lines that disintegrated in the tank.

James
 

1mouse3

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Algae? You did mention it had sat for a time. Tank being plastic, that is the only “easy” way I can think of to get a sandy/rusty stuff in the fuel……. or there is and opening somewhere that is letting stuff in the tank that is hidden by the machine……

I would think with algae it would take a lot more time than a year, like with my truck that had ten year old or more fuel. Could be a posibility looking back at photos of both my filters from when that was a issue.



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Wonder if it could be pieces of the the old lines that disintegrated in the tank.

I would think Id get a black grit from that, who knows.
 

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