Hello, I have a 2000 Kobelco SK200SR with a hydraulic problem that I can’t figure out. All hydraulic functions operated by the joysticks are very weak. The machine still works, but it has almost no digging or lifting power. The travel motors work normally and the machine drives without any issues. What I have noticed is that if I press the foot pedal for the hydraulic breaker (hammer) circuit, all the other hydraulic functions immediately become faster and much more powerful. As soon as I release the pedal, they become weak again. Another symptom is that the engine no longer auto-accelerates when I move the joysticks. It used to increase engine RPM automatically whenever a hydraulic function was operated. Now the engine stays at idle unless I operate several functions at the same time, and even then the RPM only increases slightly. The hydraulics remain weak and the machine is unable to lift a load. So far I have checked and replaced the following: All fuses and relays. Hydraulic oil. Hydraulic filters. Air filter. Pilot filter. Pilot pressure (approximately 45 bar). Has anyone experienced this before or have any suggestions on what could cause these symptoms? Could this be related to the pump regulator, unload valve, EPC/proportional solenoid, or the auto-idle/engine control system? Any advice would be greatly appreciated. Thank you!
Have never worked on one, but would want to rule out bad battery connections, good cab to battery ground, frame to battery ground, computer power and ground are strong and can keep up to load. How many hours on the unit, and does the engine stay at full RPM if placed there or does it drop like a rock when functions are engaged. Not even sure if it would have diagnostics on it, any relevant codes, being 26 years old. What type of engine and have you tried running it off a Jerry Can of Diesel fuel. Does it have any banjo bolts at filters or fuel pump with screen inside that is partially plugged. How about a transfer pump with screen inside partially plugged? Could something be over relief and bogging it down, would be a hot spot on the hydraulics somewhere if it was ? Post more info and maybe someone who worked on one will chime in. Simon C
45 bar sounds too high for pilot pressure. Should be no more than 35
The pilot pressure should be 750 psi at full throttle. do you know what mode the machine is in (H,S,FC) when did the issue start? does your display work?