Hi all. I have this 317N Cat excavator who's giving me a hard time on troubleshooting the hydraulic system. The problem is that on some hydraulic circuits, the hydraulic pump stalls the engine, such as the under carriage, and boom lift cylinders, while on the other circuit such as the bucket cylinder, the pumps are putting out low power. When i switch it from auto to manual, the power on the bucket circuit is more or less restored. I thought maybe it needs a PRV calibration and followed the procedure to calibrate it. However, when the actual Calibration starts, the engine revs up to speed 10, and stays like that, without out any hydraulic control cycling. From what I've read,as the hydraulic pilot control system loads and unloads the pump, the controller should automatically decrement the engine speed in order to calibrate it at different points. However this is not happening. Any ideas? Also i would appreciate if someone could help me with the ECM pinout (same as the on in the attached image) in order to be able to test it out. Also I have tested out the grounds on the PRV which resulted to be ok. I appreciate any help as I am confused.
Normally I'd ask for your serial number prefix, but a 317N appears to give us a choice of exactly one. I think you may be getting your calibrations confused. Calibrating the PRV involves connecting a pressure gauge and adjusting the powershift pressure to two fixed values. What you're describing sounds more like the governor motor calibration. Attached electrical schematic.
Thank you for your reply Cmark. So what is the calibration procedure for the PRV. Any ideas why i don't have hydraulic power on the bucket and 1 track?
A powershift problem would affect all functions equally so that's probably not the first place to look. Initially, I would treat them as two separate problems. The first step is to systematically check main relief pressure on all functions. Dead-head each cylinder in turn, both in and out, and write down your relief pressure (except for boom-down which you won't be able to get unless you have a big hole you can drop the bucket into). Check swing pressure by jamming the bucket into the ground and swinging left and right. Check travel motor pressures by blocking the sprocket with a steel pin. Test both sides, fwd and rev. Oh, and while you've got the gauges out, check your pilot pressure as well. How much of the testing and adjusting manual do you have? What's the history of the problem? Sudden? Gradual? Long-term? Recent repairs?
ok any fix for this problem . we have a 4mm 317 . bucket is very slow . took the pump of repaired it . test relieve pressure on stick bucket and boom set to 4800 psi . negative flow pressure is 400 psi in neutral 0 when using implement . pilot pressure is 500 psi . bucket is faster when you move it with boom or stick