I working on a PC50MR-2. The engine will stall intermittently when you return to neutral when traveling. The engine will restart each time and the issue will occur again. Once it starts happening it will occur after operating either travel lever or both levers in ether direction(forward or reverse). You can raise the machine and it will still stall. Sometimes the engine has trouble starting. The issue will not occur when operating any of the implement functions. I believe that the pump is not "de-stroking." I believe that the pilot is keeping the pump stroked too long and stalling the engine. Any thoughts? Does anyone have a hydraulic schematic for this machine?
Sounds almost the same as my problem with my PC30mr-1 in the thread a few below yours, I so fair i have taken out the Load sensing valve, the Ls bypass valve and the main relief valve and they all look fine. I'm not having much luck. If i fix it i will let you know what i did. Let me know if you have any luck fixing yours.
Well it's not really likely the pilot controls are keeping the spools actuated. But it is more likely there is a plugged drain orifice on the pump controller or something wrong with the signal circuit not draining
I had some success today, I decrease main the relief valve pressure, one turn counter clockwise and its not stalling when the using the functions, but the revs were still dropping when I stopped, but not as often. I'm tempted to lower the pressure more, but am thinking I should try and get a hold of some pressure gauges before I do to much.
All you are doing is allowing the pressurized oil to vent to tank. You will generate a lot of heat
I did some research and found out that this is somewhat of a common problem. It was recommended that I pull the main pump apart and check the balls and sockets for the swash plate to see if they were gaulded. So I did and they were pretty bad. So much so that they were sticking and causing the pump to stay stroked too long. A new pump should fix it. I'm not sure if you have the same issue but if it has high hours this could be the cause.
Thanks for the info heavyequip01, I'm really hoping I don't have to replace my pump, how did you go? Did you end up replacing the pump?
I installed the new pump. Runs great now. No stalling, no drop in RPM's now. Didn't you say you had a fair amount of hours on your machine? If so I would pull that pump apart and check the balls that the swash plate rotates on and see if they are gaulded.
It has 3700hrs so not sure if you would call that heaps, but i think you may be right, at this stage I'm probably going to get komatsu to come out and look at it.