Hi all, I have a problem with this machine, no high travel speed. I have checked and Computer doesn't engage high speed valve coil. Output fom the computer is constantly 5.8 volts. No matter high or low speed selected. Coil resistance is Ok, 27 ohms, same as other coils. I have ckecked all the conditions that computer needs to engage high speed (found in service manual), all checked on computer connectors. Speed switch - ckecked OK, connects to ground when high speed selected Front pressure sensor - OK, 5 volts when boom arm or bucked are not operated Travel pressure sensor - OK, goes from 5 volts to ground when travel engaged But computer still not engaging high speed. Did I miss checking something, or does anybody have any other ideas? Thanks all!!!
Good day Have you checked the ground is connecting Kind regards Uffex
Hi, yes I have chacked all the grounds as well, all good. But I forgot to mention the main part. I checked all the conditions that I understand. There are conditions that are not clearly explained. Service manual states that conditions to be met are also: - Pump delivery pressure : low - Pump displacement target angle: large Now to me it looks like it is looking for low load high flow situation on the pumps. If the load increases, it probably switches back to low speed. But it doesn't mention anywhere what it considers to be low. 20 bar, 100 bar, 150 bar? Same goes for target angle. I have nothing to reference to.
Good day I will take a look at the information I have, however the pump pressure is unlikely to be a issue if the only issue you have is that of the tracks. Kind regards Uffex
Thanks Uffex, I'll wait for you response. Also, do you know if this is on off valve, or variable? Asking because of those 5.8 volts.
Good day Rioamer The speed control of the tracks is by variable displacement motors the swash is controlled by the solenoid valve which you have checked out, if you are still uncertain give the solenoid an independent live & ground. I suggest you then move on to see if the motors are getting servo pressure to move the swash, put a gauge in the small line going to the central joint, this should switch from zero to servo pressure as the solenoid valve shifts. if this has not identified the source of the issue come back with the information and we can move on. Kind regards Uffex
Good day Roamer Most ECU's only deal in low voltage normal is 5 volts DC KR Uffex
Thanks for the update. You are right about 5 volts, but that is for sensors etc. Outputs to coils go to 24 volts. On the other hand, I always get 5.8 volts on the coil, regardless of the high or low speed selection. I need to sort out electrical side first, and then see if hydraulics are ok. For some reason computer is not activating the coil for some reason.
Good day If you remove and study the solenoid coil in norma circumstances it will have the voltage rating attached in some way, giving an independent feed will confirm your theory. Kind regards Uffex
Thanks. But that won't solve my problem. I'll try it anyway. But then I need to find out why it doesn't come on properly.
I understand what you mean, but if you prove that the high-speed travel coil/solenoid valve works when supplied with external 24v at least it narrows down the problem to the part of the machine electronics (I have no idea what part that is) that is required to send the 24v supply to the coil.
True that Nige
Hi all, update. As I was saying before, computer needs to see that pump pressures are low in order to engage high travel speed. Well it turns out that pressure sensor on pump 1 is gone. So computer desn't get appropriate voltage. Interestingly, machine wasn't puttiong out any alarms. And everything on it was working fine.