Komatsu WB-140 2N dies

[Shblack]

Have a problem that's causing me to pull what little hair I have out. Have a Komatsu WB-140 2N. Machines SN is A22178, it has a Yanmar Tier II 4 cylinder Diesel engine, model S4D106-2XFH - conforms to 2005 EPA requirements, which in turn is equipped with a Wooster fuel injection pump (YM7234551330). Problem began with the machine dying right after startup. Crank a bit, machine would start, then run all day. Problem has progressed to the point where the machine may start and run all day, or may die shortly after being started and refuse to run for a ny time at all. Fuel filter has about 150 hours on it and I drained the water separator. Fuel tank is completely full. Machine looses power before it dies, no visible smoke. Machine has a booster pump (silver colored cylinder) located below the fuel filter, I can hear it ticking when the problem occurs, sounds the same as when things are running. Suspect I have a fuel problem, what are some trouble shooting ideas?

Building a house, really need to get some trenches dug so we can lay pipe and get the slab poured.

 

[Dickjr.]

Does it have a transfer pump? You might check for fuel flow at the fuel injection pump inlet. Take it loose and turn the engine over to see if you get any flow. It almost has to have a lift pump of some sort.

 

[Shblack]

Thanks for the response! As far as I know only the booster / feed pump, pretty hard to follow all of the plumbing. Loosened one of the fittings on the injector pump output, first got air bubbles, then fuel. Machine kicked over and ran after that. Put a couple of pounds of pressure on the fuel tank, bleed down to zero in 5 minutes. Couldn't find a fuel leak, but assuming we have an air leak on the suction side of the feed pump, in the process of replacing the fuel line between the tank and water separator and the separator to the feed pump. Good opportunity to learn about the machine, hate doing it with a crew standing around. Anything else come to mind out there?

 

[Delmer]

Yanmar Komatsu Wooster Tier means nothing to me, I'm just winging this so to speak.

First, if you have an inline Japanese injection pump with a priming pump that has a one inch round handle that unscrews and pops up to pump, then take the banjo bolt out of the BOTTOM of that transfer pump, and unscrew the screen that's INSIDE that banjo bolt. Blow the crap out and put it all back together, without loosing the aluminum washers.

That's not the most likely issue, but do it anyway if that's the setup you have.

Second, check the seal on the water seperator and clean the screen inside.

The air you found is the smoking gun. You have a plugged fitting/line somewhere and/or a cracked or leaky hose or seal somewhere, most likely between the tank and the pump. Possibly something in the tank. If it's all to confusing for you, put a tee somewhere in the system and run a line to a pressure/vacuum gauge in the cab, that will show you what's going on with the fuel pressure when it dies.

 

[Shblack]

Delmer:
Thanks for your response. The injection pump has the 4 outputs arranged in a square, and no it does not have a priming pump. I have gone through the breakdowns for the water separator, piping and filter in the parts book, searching for words like filter or screen, have not seen anything. Unfortunately the parts book does not have a breakdown for the injection pump on our machine (there is one for the in-line output one on a Tier I engine), guess they figure it's throw away. We replaced all the suction side fuel lines today, seemed to run great when we fired it up. Going to dig trenches tomorrow, will report on how it behaves. The water separator sounds like a good next step if the problem is still there, maybe a start would be to pressurize the tank again and spray it with soapy water.

 

[Delmer]

Just because it doesn't leak fuel, doesn't mean it won't suck air.

 

[thepumpguysc]

Your inj. pump is a Yanmar "MP" pump.. no access to anything..they are sealed pretty tight.
They WILL NOT tolerate ANY water.
You can pull the inlet banjo bolt on the inj. pump to SEE if its rusted.. that'll give you some idea as to the problem..

 

[Shblack]

Changed the fuel lines from the water separator to feed pump, feed pump to fuel filter and fuel filter to injector pump plus the return line. After bleeding the lines, machine started right up. Did some other maintenance on it, then went to work. About 30 minutes later it died, we are back to the same routine crank for a bit, machine eventually starts, then looses power and dies. FYI - Friday I had a fellow that maintains equipment for the contractor working on our house look at it, he was the one who reported air bubbles when he cracked the nut on one of the injectors, had him replace the fuel lines since my day was pretty full.

Assuming air is still getting into the fuel system seems like the options are limited to the water separator and the pickup tube in the fuel tank. So this AM I started with the pumpguysc's suggestion and removed the bolt in the banjo fitting on the fuel line feeding the injector pump to inspect - clean as a whistle. While I had this apart I turned the key to "run", which started the feed pump. No fuel came out, no air, nothing. Obviously a problem. So I broke the suction line at the input to the water separator and put a little pressure on the fuel tank - fuel came pouring out, don't have a blocked pickup in the tank. Next I took apart the water separator, it was a cruddy mess with lumps of black stuff filling the bottom and a messy element. Good to find something, cleaned it up, blew the crud out of the pickup tube / bolt and tried to find a replacement element. We live in a very rural area in the Bible Belt, so finding something like this on a Sunday was not successful. So I cleaned everything up, blew the large lumps off the filter element and put everything back together. Cracked the bleed nut on top of the separator, put a little pressure back on the fuel tank, drove the air out. Put the key back to "run", now fuel pours out of the line feeding the injection pump. Buttoned things back up, cranked the engine and she fired right up. Loose crud floating around in the water separator bowl may explain one of the early symptoms, where the machine would die when driven up slope. Will order a new element, and also replace the spin on fuel filter, concerned that some of this crud may have migrated to the filter.
Interesting note that the manual lists draining the water separator as a 50 hour task, but there was no mention anywhere on replacing the element in the water separator, it wasn't even listed on the consumable parts list. Makes one wonder if it had ever been replaced. What was the black crud - algae? I run ultra low sulfur pink diesel with an algae inhibitor.

Thanks for all your suggestions, I am a real newbie when it comes to mechanics. This would probably be a trivial problem to you veterans out there, but it forced me to learn more about my machine. Now to figure out why the temperature gage has stopped working, the fix a leaking seal on a final drive.

 

[Delmer]

If the element you're talking about is a screen, then it's probably not meant to be replaced on schedule. Just blow the crud off it and put it back. The black gooey stuff may need brake cleaner or hot water and detergent to get off.

It's either algae or asphalt, what difference at this point does it make? Both are from aged fuel.

 

[Shblack]

It's actually pleated paper

 

[Delmer]

what the heck do I know? If you got the numbers off the element it shouldn't be too hard to find. filterspro dot com is a place I've ordered from if you can't find it elsewhere, they have a good selection at good prices if you buy enough to make the shipping reasonable.

 

[Shblack]

Found a seller on eBay that had new old stock Komatsu filters. Ordered both. Machine has been running great this AM, more power too.

 

[Dickjr.]

I had a similar problem with my dump truck. It had the black slivers of stuff in it. It took probably 8 new filters and I put Sea Foam algae treatment in it and it cleared up. My issue was in the tank. You may want to pick up a couple extra primary filters until it clears up.