I have had the komatsu dealer out twice,replaced lock solenoid have power to it. Replaced self reducing pressure valve.Have had pumps tested and are around 3300. Help this is going on two weeks and a lot of money down the drain.
Always fires up and runs fine, tried to start with safety switch up and it won't let me, like it should.
Anyone out there?
Does all hydraulic stop at once?
Keep in mind people the people who might help you with your problem are not on here every second of the day so sometimes you might have to wait a day or two for an answer. What year and how many hours do you have on this monster? The pressures you give are low from the experience that I have.
Yes all hydraulics stop at once, and pumps have tested to spec by the komatsu technician. Sorry for the impatience just struggling.
yes
pc 200-7lc 7200 hrs
yes
It sounds like a bad ground connection or a wiring harness issue. Have you checked the monitor panel for fault codes when the problem happens. I would say if there are no fault codes when it happens you have a problem in the wiring for the pilot shutoff control. Do you have a book with a wiring schematic?
no error codes,I only have the operation and maintenance manual.
Can you hook up volt meter or light to lockout solenoid to see if there is an intermittent power loss?
I've hooked a multimeter to the wires before the lockout solenoid and I have 27 volts
I mean so you can see when it happens
no,the voltage is constant whether working or not
Voltage not needed to keep solenoid open or closed?
The system is controlled through a ground connection. Voltage is always to the switch. Close the switch and the connection now runs to machine ground. If like the Dash 6 machines there will be a ground in the cab behind the seat usually over by the boom side corner of the cab somewhere around the computers. That will likely connect to a jumper connection to the cab mount bolt or something. They are not identified or located in a drawing in the books any longer that I have seen. What you can do to check this is to connect the non hot side wire going into the switch to ground and see if that keeps the pilot controls working.
Thanks for the information ,will give this a try, it is -20 below wind chill so I am waiting until tomorrow to apply the information you have given me.
If you bypass the safety lockout, fix the issue, don't operate the machine without the lockout. A fella was killed here years ago when the lockout was disabled on a 245 cat. Operator left the seat with the machine running bucket down, but not on the ground. His coat caught the joystick as he jumped out, and crushed a guy running a walk behind tamper against a concrete wall. Only takes a second.
I'm not saying to bypass the switch. Only to hook the ground side lead to a good ground outside of the wiring harness.
I grounded the solenoid to the machine and still no function.
I'm not real sure where to send you from this point. Can you plug a gauge into the pilot system somewhere down stream of the pilot shut off valve? Maybe the spool inside is stuck in the close position.
It worked for about 4 hours today, went to lunch ,came back no hydraulic function.
I have pressure downstream of the pilot system
Which spool would I start at?
I would say there is a manifold block behind the cab somewhere that has a bunch of electrical switches. You should be able to tee off one of those switches to see if you have pilot pressure when the system is acting up.
A friend had similar issues with his komatsu , tech was out many times replacing everything under the sun, in the end it was a bad wiring harness at the bottom of the boom, several wires got damaged, he fixed the wires and all is good, the dealer had a 6K bill for him for the parts change outs, after chatting with dealer they worked it out to a much lower amount..
Sometimes we over think stuff when trying to fix things in a hurry. My father always said electrical issues are simple if you trace from fire to switch to function. Without a service manual it can be hard to do that. Perhaps a live jumper wire from the battery to try and trigger pilot functions. We had a Cat do that but it had been vandelized and the dash had been smashed. Once replaced the issue was solved. Hopefully you solve the problem soon
I have power to the pilot control solenoid,but no functions.
I have a komatsu 200 doing same exaxt thing with 7600 hrs did you ever figure out the issue?