Issues with KX-41 excavator.

[MudRunner]

I have a late 90's model KX-41H that has been having some issues lately.

3514 hours currently, we bought it used with 3100 hours on it. I've changed the oil every 100 hours using Shell Rotella T and have pretty much followed the book on maintenance. Not sure about it's past history.

Anywho, lately we've been hearing some sort of tap/knock when the engine is under load. It doesn't sound like rod knock to me (I'm an auto mechanic) but I don't have much experience with diesel engine sounds. The oil comes out clean on the dipstick. The engine also bogs down at random, almost like a fuel starvation issue, but it has a new filter, and plenty of fresh diesel. Sometimes it will go from wide open throttle, and slowly bog down until it dies (just sitting there). Trying to move the excavator kills it nearly instantly.

I'm just very lost here. All the fluids/filters are good. I'll be taking an oil sample tomorrow and sending it to Blackstone Labs to see what they can find in it. Any suggestions in the meantime?

Thanks!

-Zach

 

[MudRunner]

Thanks Vic! Yeah, 100% hydraulic. It has a leak somewhere that I need to track down and fix.

The hesitation/bogging issue is fixed though. While tracking the fuel lines, I found another fuel filter! It was the inline-type commonly found on gas tractors.... looks like someone added it. Anywho. the media had pretty much collaped, and clogged the line. So, replaced it with a straight fitting since I have the spin-on filter to catch debris.

Still has a little tap/knock that hopefully oil analysis can diagnose. Who knows, it may be normal.

 

[Bulldog]

My L 3000 had a strange sound to me when I was digging with my backhoe. It was the same type noise that you are describing. It has been making it for 10 yrs now and nothing has happened. The only time I ever hear it is when I have my backhoe on it. I just figured it must be the type of load digging puts on the engine.

 

[MudRunner]

^Hmm. I wonder what it could be?

The ticking seems to have calmed down some after an oil change, but there were only 23 hours on that oil. Sent a sample of it off to Blackstone today. I'll post the results when they come in.

 

[Bulldog]

I have been thinking more about that ticking problem. It could be the injectors you are hearing when they fire the fuel in cylinder.

I went from a Cat 980 G loader to a Cat 980 H. They both have 3406 engines but the H model is called a C15 instead of 3406. One big difference is the C15 is electronic and the G model is mechanical. They sound nothing alike. The old one makes all different kinds of noises that the new C15 doesn't. The electronic injectors are very quiet. Not only quiet but work totally different. Elec. injectors fire in fuel 7 times per cycle. They claim to be more fuel efficient but I don't see much difference. It don't smoke though.

 

[MudRunner]

Interesting that you'd mention that. The ticking seems to have stopped since the fuel filter issue was resolved. That's a possiblilty, or it could have been the lack of fuel causing a lean condition, making the engine knock (though I'm not sure that diesels really do that?).

My engine is the D1105, if I remember correctly. It does smoke some under heavier loads (digging, cutting roots, etc).

 

[Bulldog]

Most of the time people may be able to hear a noise but never try to find out what is making it. I myself want to know what makes a strange or different sound. Sometimes being able to identify a noise when it first starts may save some big bucks down the road.

 

[MudRunner]

Yeah, I'm a member of a few online car forums. Too many people go, "What's that noise?" then turn the radio up and forget about it.

I just got done rebuilding a small-block Chevy. I've re-adjusted the lifters twice now because I'm so OCD about the noises. I'm just picky!

 

[Bulldog]

The turn the radio up move never works out good for anybody but the mechanic that will be paid to fix it.

 

[616jim]

just saw your post from a few years ago. i have two comments. the problem you may have had may have been a dirty fuel filter or water in the fuel. i worked as a mechanic on golf course equipment and we had problems with both. (especially when our fuel supply was low)

secondly, i need a electrical schematic and hydraulic schematic for a grey market excavator, 17 hp. do you have one?