04' New Holland LB75.B backhoe "bubble in my fuel"

[maddmechanics]

I've recently acquired a backhoe that's been sitting for a year, possibly longer. I went ahead and removed and cleaned fuel tank, new filter, new batteries, fresh fuel ect.... It will turn over and I even had it running, for about 2 minutes. And I got it to start several times, but it would just stop. I have bled the lines and it holds pressure all the way to my primer pump. I bled the injectors and it'll start right after I do, but then it cuts off and I have air at my injectors again but not at my primer pump. And it goes back to not starting and now it won't even start after the injectors are bled. I'm just at a loss on what to do next. I really just need it moved to my shop but I can't get it to run or lift buckets. Any help would be greatly appreciated. Thank you.

 

[RickB]

Replace the rubber fuel supply line exiting the tank.

 

[maddmechanics]

Yeah I have, and I checked the solenoid and filter again. i'm going back through all the injectors and their connectors. i'm thinking that there's a blockage some where because i'm not really getting the fuel that i think i should be getting. i didn't realize that there were two solenoids on the injector pump, so I've only really checked the one. my lines look good. my lift pump is working and i can prime it as far as the filter and then at some point past or at the injector pump i'm getting air bubbles, but i'm not leaking any gas. There is a steady stream of bubbles with the fuel every time i bleed the injectors. i got it to run a little yesterday for a few seconds and it kept shutting off and it did that several times. i'm not sure what changed between then and now but i cant get it to start or even puff smoke today.

 

[Tx Jim]

Have you checked to be sure fuel tank is venting? Attempt starting with fuel tank cap removed.

 

[maddmechanics]

yup i tried that too, to be honest i don't have a lot of experience with diesel engines so a lot of this is new to me. my Boyfriend and I run a mechanic shop and we work on a lot of ATVs and dirt bikes and we do a lot of welding. I have experience operating heavy machinery and welding on it but not mechanically working on them. i went through the basic stuff like cleaning the tank, changing the filter, new batteries, fresh fuel and bleeding lines. it started up and ran several times but i cant throttle up and no response from gas pedal. i checked what i thought was the main fuel shut-off solenoid but after finding a second one i came to realize it may have been the cold start solenoid that i checked and to be honest it seemed to be working backwards. i'm going to remove the other solenoid today, I'll update and let ya know how it goes. if i can get it to the shop this would probably go a lot smoother. I got to be able to lift the buckets and get it running first. SMH

 

[EddieWalker]

I have a New Holland 555E, so it's a bit older then what you have. My tank is metal and there is rust flaking off of it. The mechanic at the Dealer said that if the tank is not kept full when stored, this becomes very common. He also said that there are two lines going into the tank, one for bringing the fuel to the engine, the other to return the fuel back to the tank. Blow air through both lines and then switch them. The return line doesn't go as deep into the tank and it's less likely to pull stuff out of the tank.

On mine, there is a small screen filter inside the glass bowl of the fuel pump. Take it all apart and clean it out with carb cleaner. I just spray until everything is clean. Tale off the fuel filter and blow all of those fittings out too. I just stick the air nozzle into the line and blow air through it and see if anything comes out the other end. It's surprising to see how much crud is in there when I'm having fuel issues.

I added a cheap, plastic, Fram, inline fuel filter for gasoline engines to the fuel line before it gets to the fuel pump. I replace it every year in the Spring when I do all my filter and oil changes. Since doing this, I haven't had any issues with my fuel system.

 

[rScotty]

Eddie's advice is about standard for older hoes. Amazing how much crud there is in an old fuel filter. Typical fuel filter woes are that it starts OK but won't rev up or dies after a couple of minutes. When mine is getting clogged the first symptom is that it won't rev past about half throttle.
I guess it's possible that air is getting into the injector pump, but although I've heard of it I don't know anything about that.
There's a guy who posts on TBN "thepumpguy" who knows all about injector pumps. Give him a shout. He may know of some simple test to tell you where to look.
good luck,
rScotty

 

[thepumpguysc]

1 thing I can think of is the fuel filter..
Is it the type that has the long bolt that sandwich’s a bowl on the bottom.??
If YES, U HAVE TO PUT THE TOP ORING UP IN THE FILTER HEAD.. NOT ON THE FILTER..
Double check that..

 

[RickB]

1 thing I can think of is the fuel filter..
Is it the type that has the long bolt that sandwich’s a bowl on the bottom.??
If YES, U HAVE TO PUT THE TOP ORING UP IN THE FILTER HEAD.. NOT ON THE FILTER..
Double check that..

It's got a spin on Bosch filter. The rubber fuel supply and return lines on these machines are famous for getting porous.

 

[IH3444]

My "just in CASE" bulldozer has a last resort fine wire mesh cone filter right at the junction of the fuel line inserted into the injection pump. Pointy end if cone into the injection pump. I very carefully remove it from time to time and clean it. This final, "fail safe" fine wire mesh filter is after all three main in line filters. The factory filters below the fuel tank, the primary paper filter, and then the secondary paper filter. I use all OEM filters. You should check to see in your shop manual if yours has a final cone fine metal mesh filter such as this. My Volkswagen gasoline Passat has one as such before the fuel enters the fuel injection metering unit. So its not unique, several manufactures employ the final "fail safe" method of ensuring only clean fuel reaches the injection pump.