Hi We have some serious problems with our machine. The machine runs perfectly for about 10-15 minutes, and then the engine stops. After cooling down it can be started again. The local Kumatsu dealer mechanic diagnosed a fuel pump replacement, but this did not fix the problem. Now, after new diagnosis, he says that the block valve has a crack, and it is supposed to be the valve controlling the bucket. He measured, that not enough pressure was delivered. I think he said 210 bar and supposed to deliver 280. It seems that the valves can not be purchased individually, so a complete block is needed. This is really expensive (>$12,000), so we would appreciate any comments/thoughts. The machine has only run about 2800 hours, and has run smoothly until now. Has anybody experienced something similar? Kind regards Eric
The engine shutdown issue sounds like a fuel problem. I have never seen that model but what I have seen in the past was the fuel tank was mounted behind and partly under the cab. The ones I worked on had plastic tanks with a sediment bowl or fuel strainer mounted there. There also may be some banjo bolts that have stainers installed in the center of them. Check all those bolts from the tank to the engine. When checking out the engine problem why did the mechanic check hydraulic pressures? I'm not sure about that pressure reading either. Your mechanic needs to show you something in writing that gives the factory spec pressure for the bucket. If you fill the bucket with dirt and hold it up in the air with sides level to the ground, does the bucket drift down? There are more reasons than a cracked valve for the pressure to be low and it might be meant to be that way.
Agreed , sounds like a fuel problem, is the fuel shut off controlled by solenoid or mechanical linkage, If solenoid, may be failing, have had same symptoms in a truck, run for 20min then shut down, and restart when cooled down. As to hydraulic pressures, were boom, arm ,and bucket circuits checked or just bucket. I would be asking your mechanic how a $12000 valve block is going to cure an engine shut down problem when he has already replaced fuel pump with no result. A good rule to work by is to diagnose problem first before throwing parts at it. Best of luck.
Ck temp to see if the motor is actually overheated, or just up to normal operating temperature. If normal, that eliminates a overheating shutdown. Then look at fuel delivery. When it shuts down-try some fuel or WD-40 sprayed into the intake. If it fires, you know where afuel delivery problem exists
Thanks for the replies. We also suspected fuel delivery problems before we contacted the mechanic. We emptied the tank and blew the hose clean as the first step. We will check the banjo bolts to make sure. @bwmwaima: I think the rest was also checked, but I am not sure. We were not there when he was working. The shut off is solenoid. This was the first the mechanic suspected, but i am not sure if this was included in the fuel pump change. We will check again. We will also try the spray trick. It did not seem to overheat. In the mean time, I found the individual valves on alibaba.com at $450 each. If we decide to try to change the valves this maybe the cheapest way. Thanks again for your time. I am about to go on a small vacation, but I will keep you posted. Regards Eric