Ive got a cat 289c high flow xps two speed sn:cat0289cpjmp01393 that will bog the motor almost to a stall when you actuate the hydraulics. For example; when you are driving the machine forward and simaltaniously lower the loader arms, the machine will bog down and almost stop driving completely. The electronic fuel pump has been replaced, as well as the hydraulic and fuel filters. The hydraulic pilot pressure and relief pressures look to be correct by my gauges. I am lost on what could be the issue next.
If you drive back & forward without operating the lift/tilt controls, or if you operate the lift/tilt controils with the machine stationary, does it appear to operate normally..? What pressures did you see for the implement pilot and main relief valve..? Specs are 400 +/- 30 psi @ Low Idle and 480 +/- 30 psi @ High Idle for Pilot. 3335 +/- 100 psi for main relief. Have you tested the accumulator nitrogen pre-charge pressure.?
Did this problem develop suddenly or has it got worse over an extended period of time.? Does the engine black smoke when the RPM gets dragged down.? When you changed the fuel filter did you clean the filter head and are you sure you didn't lose the o-ring..? Ths thread may give you some ideas, especially the photos on page 3. HeavyEquipmentForums
This machine is new to us, so I am not sure how the problem came to be. (over time or suddenly) The machine does not smoke when it is dragged down. The fuel filter was replaced with a genuine CAT filter. The entire filter housing was removed and cleaned well. The fuel lines have no signs of leaking nor sucking air. The o-ring on the bottom of the filter in your tagged link is still in position and looks to be in very good shape. The pilot pressure and relief pressures are exactly where they should be. The accumulator pressure seams to also be correct to the Cat service manual (
900 ± 100 kPa (130 ± 15 psi) then HIGH idle. The pilot pressure should rise to 3500 ± 200 kPa (500 ± 30 psi).