Hello, I have a JLG forklift G12-55A with this problem: The hydraulic pump gets very hot and the steering orbital pump begin noise , and the engine does not stay at idle correctly. It just when the joystick function moves can the aceleratorpedal be acxtivated otherwise the engine can race the idle and keep running the machine Work already done: Replaced the harness from engine to ECU Changed filters Checked fuel lines But the problem is still there. Has anyone seen this before? Could an overheating hydraulic pump affect engine idle? What should I check next: hydraulic pressure, relief valve, pump, load sense, sensor, or ECU input? Any advice would help. Thanks. we appreciate your help.
Sounds like the pump is stroked up all the time.
Yes, the pump isn't moving enough fluid to cool itself (or feed the steering pump) and has become a load on the engine.
thank you for your answers . by continuing to move the Joystick in cert point the machine rise the rpm by self and can keep running for a while but the hydraulic pump came to hot i measured and is over 300 f . about this we clean up the check valves but still same any suggestion?
Have you done a hydraulic pressure test?