CAT 311D excavator - low engine power/hydraulic overload

[agris.liepkalns]

Hi guys!
Need advice on the following problem.
When excavators boom is pulled up till the end and you keep pulling joystick up, the excavators hydraulic is overloading and shutting off the engine. The same happens with bucket closing function and moving one of tracks.
When we checked the hydraulic pressure on the service menu - there is a 100% difference in section pressures when idling, which shouldn`t be like that and when the main boom is pulled up, the difference grows up 5-6 times.
Its clear that problem can be in main control valve or in hydraulic pump valves, but maybe someone can give more specified information from what to start...

Thanks!

 

[digger_hunter]

could me the pump pressure sensor is malfunctioning. Did you check the pressure in computer compares to actual using a gauge? the issue could also be the PRV is malfunctioning but better check the main pump sensors are working correctly before that. we have had several where the sensor reports a lower pressure than actual so it throws off the PRV function. also check the wiring to the sensors, there was a an issue on many C and D models where the wiring insulation would flake off and that causes the wires to touch and cause various issues and most of the time the wires to the pressure sensors were the ones affected

 

[Nige]

Try swapping the sensors between #1 and #2 pumps maybe, see if the difference moves with the sensor or stays with the pump.?

 

[digger_hunter]

actually to check the wiring you could swap the plugs first if the harness is long enough to do that before you swap the sensors