Ill try keep this in-depth and brief as possible. Purchased second hand ec290blc excavator, ex logging machine. Common Vecu fault, replaced with new ecu machine ran perfect, leaked like a sive but did everything I wanted it todo. Resealed pump servos, pilot pump, main valve, replaced various hoses Issue it's having is it will not auto idle down. All work functions work fine on the dial. Main valve has what could be described as noise or harmonics from front pump loading up ( closest to engine) to the lhs main valve bank. pulled main relief resealed and wound out, was maxed out on pilot boost and main pressure ( logging company known for ******* with stuff they have no idea on) returned to respectable settings. Still no change. Machine will idle down when pressure sender from middle valve segment is unplugged. And idles up and holds when plugged in again. Have tested incab switch with others and does not change. Any ideas would be great. Probably missed a few things but will let someone know if I've touched something. Cheers and thanks
Good day & welcome I guess we are talking auto idle see attached explanation, pump noise from only one section a little unusual. Could there be disturbance to the regulation? Kind regards Uffex
Thanks for the file mate ill go over it and see what I can find. The noise is related to the main relief being screwed up, it only relieves one side of the valve block i am unsure how the other side is regulated as it does not have a relief the same as the lhs of the valve I will gather some photos tommorow to make this more clear. These ports are joined in the valve internally the centre segment top being the main relief.
Good day May I suggest you try and source a hydraulic schematic as the standard 290B has only one relief valve serving both pump sections.You could follow the pump delivery lines and take photo's Kind regards Uffex
Yes thats correct, I have the volvo manual, I will take photos tommorow as it's dark at the moment