I have a Cat 259b3 compact track loader. Yesterday the loader started operating sporadically. Sometimes it works,

Hello,

I am not certain about what you mean but, it sounds like you are saying you are losing power?

If so, the best place to start is to replace the fuel filter. When you do this, listen to the electric lift pump when you prime the fuel system.

You may need a helper to turn the key switch to the start position, just barely engaging the starter. This will latch the fuel relay on and you will hear the pump run without the engine running. Leave the key switch in the on position after bumping the starter. The pump will only run for a minute or two so, you will need to repeat the to purge the air from the system.

While priming the engine, perform your normal inspections of the air filters air supply pipe. Look for loos or kiked air lines or fuel lines. If nessacary, clean the engine to help view all the fuel lines to verify none are damaged.

Please describe what is happening and what you do to correct it when you can.

No warning lights, no need to press any buttons?

Do you have the monitor control in the upper right console with the large display screen?

Ok, without the monitor, you cannot troubleshoot the system. The B3 machines rarely have it anyway.

I would inspect the wiring from the joystick back to behind the seat. You do not want any damage to the wires. Then raise the cab and inspect the wiring from the cab pass-through connector to the ECM. Again, you do not want any damage to the wires.

If the wiring is good, I would replace the joystick assembly. No repair parts are available and you can replace it with the handle for only a bit more money. It is worth it if you have any wear on the handle.

I have seen several of these fail and found it much better to replace the assembly with the handle as it is often damaged or difficult to remove.