Cat 314C LCR stuck in low idle mode

[Kjartan]

I have a Cat 314C LCR excavator that is stuck in low idle mode (engine will not rev up when I turn the engine speed dial).
My first thought was that the wiring from the low idle button to the computer was faulty but I have measured the resistance of the wires and examined them and they seem to be fine.
Does anyone know of a way to reset the computer so that it will exit this low-idle mode, or any other way to fix this? (Breaking the main electric circuit doesn't work)
I can rev it up with a backup switch under the operator's seat but the output of the hydraulic pump is reduced (some kind of a safety measure, according to the owner's manual) and it's annoying to operate it like this for a long time.
The weird thing is that there is another switch that is supposed to enable this backup rev change switch but the rev change switch works regardless of the other switch's position and therefore I'm thinking this maybe is a computer problem.

Any ideas would be appreciated

Kjartan

 

[ben46a]

Kind of sounds to me like one of the backup switch wires is chaffed and shorting to ground or the backup switch itself is faulty. I would be inclined to start looking there first.

 

[dirtdobber1]

I have a slightly older and smaller machine than yours. My low idle switch is in the top of the right hand joystick and is user activated. Any chance your switch has failed (if yours is like mine) and is continuously in the position for low idle?

 

[Kjartan]

Thanks for your answers!
I forgot to mention that I had already checked the switch of the right hand joystick (sounds like they are the same) and it is working perfectly.
I checked the backup switch and it seems to be working but one of the wires is probably the cause of the problem. At one point two wires merge into one that is connected to the switch. One of the two wires is connected to the computer and has 12Volts but the other one leads out of the cabin and has 5Volts (definitely something wrong here). I thought that the only working voltages in the machine should be 12V or 24V. Do you know if I am right about that?

 

[Nige]

A lot of electronically-controlled machines use 5V and/or 8V stabilized power produced by one of the electronic controls for certain functions. Without looking in detail at your model this may be one of those cases. If you would like an Electrical Schematic for your machine then please PM me with your Serial Number and an e-mail address to which I can send the document. You may find that you have to have a minimum of 3 posts on the forum before you can send PMs.

 

[Kjartan]

I see, but I can't imagine that two wires with different voltages should be connected together to form a single wire. I also measured the resistance between the 5V wire and ground to be about 20kOhm, which seems strange to me.

 

[simonc@e81]

i have a 314c lrc doing the same thing with same test results where you able to find the problem. thanks and any help is appreciated!!

 

[DEMLONE70]

Serial number ?

 

[simonc@e81]

Serial number ?

pca01222

 

[DEMLONE70]

U may have problem with the governor motor

 

[simonc@e81]

U may have problem with the governor motor

is there an test i could run on it to confirm. One thing to i would like to note is the green low idle mode light is on and will not go out, witch is making me lean towrds a coumputer input problem. The backup controles work fine both in auto and manual position. thanks for the replay and help

 

[DEMLONE70]

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