I have 2002 Komatsu WB140-2. It will crank but not start. It was running fine, and would always start easily. I started to hear a warning beep, which looking in the manual meant low fuel, low battery charge, or transmission temp. One or two times after hearing that warning beep, I would no longer start. In the past it had a bad battery connection. I repaired that and cleaned the ground contact. I changed the fuel filter, but I believe I forgot to fill the filter with diesel before attempting to start, but I did prime the system. I replaced the primer pump, because original one was leaking. The manual did not mention the filter in the water separator, but eventually found that one and replaced it. It was pretty dirty, so thought that was the problem. However, that did not seem to help either. Other things that have been done to it: new battery, new starter, replaced fuel lines, and cleaned the screen where the fuel comes into the bottom of the primer pump. If I loosen the lines at the injectors, I will get about a 3-6 inch spurt of fuel while cranking. While cranking I will get a small puff of smoke, and a small sputter, but not enough to start. Air filter looks fine, and have tried it without the air filter to eliminate that as a problem. What am I missing? Any suggestions on what to try next? Thanks!
Does it have a manual shut off or does it shut off on the key?
It just shuts off with the key.
Maybe the fuel solenoid or wiring for the fuel solenoid is weak. Have you tested for power at the solenoid while cranking. How far down does your new battery go while cranking, does the engine spin close to 250 RPM while cranking. How many hours on the unit. Could it possibly be sanded. Have you tried with air filters out to start with a very heavy spray of WD40 while at the same time shooting 2 electric heat guns worth of hot air at the same time. WD40 increases compression, and heat guns help ignition of diesel to happen. Let us know what happens. Simon C
Thanks Simon. Fuel solenoid seems to stay on while cranking, but testing the solenoid while cranking is worth a try. I try to keep the cranking to around 10 seconds, and I usually get 10-12 cranks before I need to recharge. The tach does not register any thing while cranking, I need to think of a way to check the RPM's. The unit has about 2500 hours on it. I am not sure what "sanded" means. I have tried WD40, but maybe not a heavy enough dose. Heat gun is an interesting idea. Something to try tomorrow.
Sanded means that sometime in the past the air intake plumbing developed a leak and was sucking dust into the cyklinders and thus the compression rings are worn out and the cylinders are worn in lots and it becomes very hard to start. The idea behind any oil into the cyklinders is that it increases compression significantly. If it won't fire with these things you will probably be looking into the fuel system. Simon C
That makes sense. Thanks again.
You should check the fuel solenoid with an ohm meter. It should have resistance through the coil. Maybe three to five ohms or so. If you have a book it should give you the reading that you need. Do you know which engine is in it?
Sounds like you're getting fuel to the injectors, so I'd start looking beyond just filters and lines. The warning beep before it quit could be a clue—I'd check battery voltage while cranking and make sure the fuel shutoff solenoid is actually staying energized. A weak electrical supply can crank the engine but not let the fuel system work properly. Since you're getting a little smoke and an occasional sputter, it almost sounds like it's still got air trapped in the fuel system or isn't getting enough fuel pressure. I'd bleed the system again thoroughly and verify the lift/primer pump is moving a solid amount of fuel. Also check all fuses, relays, and engine safety shutdown circuits. Sometimes a bad sensor or relay can stop fuel delivery even though the engine cranks normally. The fact it was running fine, started beeping, then gradually became a no-start makes me suspect an electrical issue or fuel shutoff problem more than a mechanical engine failure.
Thanks. I will check the fuel solenoid. The engine is a Yanmar, model number SD4106-1FH.
Thank you. I will try these things also. One the things that I did try in the past was to pressurize the fuel tank to about 15 psi. Partially to add more pressure and to check for leaks. No leaks were found. There might have been a little more smoke at that time, but not certain.
Sounds like you need a new battery.
It is a new battery, because I also thought it might be the battery. The old battery also checked out fine (load test and hydrometer), so I have been hooking them up in parallel.
I guess I should clarify. After about 10-12 cranks the started gets pretty hot. I generally feel it is time to let it cool down and recharge the batteries at that point.
The battery voltage is 12.8, at no load and 10.5v while cranking. The starter seems slow to me, but I have not figured out a good way to test the speed yet. The fuel solenoid is staying open. On this one it activates a lever, so it is easy to see if it is working. I also manually held it open while cranking to see if that made any difference, but no real change.
I also tried what Simon suggested, the WD40 and heat gun. Definitely more smoke, but still no start. May try that again later in the day, when everything is hot.
Sounds like you still have a fuel problem, possibly along with a cranking speed issue. Is it possible a hydraulic strain is in the pump, while turning over? I would look for a plugged strainer in some of the fuel lines. Those buggers can be hard to identify! With 2 batteries connected, you should be easily good for 30 seconds of crank time, before anything gets hot. Seeing as you had a bad connection in the past, new battery and starter cable, would be in my list. If the cables are bad on the inside, you could be drawing a large amounts of current, that is spent on heat and not starting.
The hydraulic stain is an interesting thought. I did notice the front wheels were easy to turn, while cranking. Something to check. The new battery cable is also a good idea. Thanks.
Made some progress today. Definitely have some hydraulic load going on while starting (Thank you HarleyHappy!!). I briefly got it to start while actuating the outrigger lever. The in-between areas relieved enough pressure to allow it to start. Now I just need to figure out what is causing that issue, but first success I have had in a long time. I really appreciate everything that suggested things to check!
Try putting the front loader lever in float. Even with that load the engine should still start.
Thanks. I will give that try tomorrow.
So the backhoe is running again. Thanks again to all those that have helped me out!! The problem falls under one of those, "I can't believe that is what has caused me so much grief" Next to the backhoe controls, there is pedal which I believe is for a hydraulic boost in hard digging situations (Its function is not really clear in the manual). It is a feature that I have never used or needed, since I live in a giant sandbox. Apparently that pedal was accidentally pushed at some point, and (probably due to lack of use) did not return to the neutral position. Started right up after deactivating that pedal.