Cat 312B calibration error

[digger_hunter]

Hey guys,

I have a Cat 312BL and the auto idle is not working, i mean even when i press the button on the RH joystick it won't idle down. I tried to calibrate the governor but it keep showing 70 HF 00 when i start the calibration, i mean to be exact when i goto item 70 to calibrate and then press button 8 to start it says 70 HF 00 and then i press nbutton 8 again and it says 70 HF 03.

Any ideas whats wrong? the book says load is applied but what can that be?

 

[shinigamix2x]

had a problem like this with a 320bl, once the oil is well within operating temperature range and the boom pressure sensor and pump sensor are good, i've made about 3 attempts and it finally went through... i can't say for certain but work the levers a bit and retry again...

 

[Nige]

I think it could have something to do with the fact that the hydraulic oil is probably not hot enough and therefore you're getting drag of some kind on the pump end. Also maybe your pilot controls might not be neutralizing 100%, thus causing a hydraulic load on the engine.

Are you sure it doesn't say 70 Hd 00 rather than 70 HF 00..? If it does then there is a procedure to correct that before doing the calibration..........

Perform the following operations when the character display shows "70 Hd 00"..............

Depress the fine control mode switch and hold the fine control mode switch (25) until the character display stops blinking.
Depress the boom priority mode switch (23) or the swing priority mode switch (24) in order to select the data that is used as the calibration data.
Depress the boom priority mode switch (23) in order to select the previous calibration data.
Depress the swing priority mode switch in order to select the default calibration data.
Depress the travel alarm cancel switch (22) in order to memorize the calibration data that has been selected.

 

[Mobiltech]

If the auto idle won't come down to idle you probably have a faulty pilot pressure sensor saying you are using a function when you're not. The sensors and the wiring to them are a common failure.

 

[digger_hunter]

Hey Nige,

Thanks for the reply, but today I tried again and basically i get "70 H 00" and then i press 8 again and i get "70 HF 03" I put 70 HF 00 by mistake in my earlier post. also i checked all the out puts from the pressure switches etc and all the outputs check out and the pressure switches are being read correctly on the computer. There was one anomaly that the hydraulic return filter switch would not reset, i am not sure whether it is actually blocked because we put a new one but i think the switch busted because we have had a few with that switch in pieces!. Anyways shorted the signal wire to ground on that connector to the hydraulic return filter and the block warning went off but still no auto idle or auto idle switch on lever still inop.


Could it be a faulty stepper motor potentiometer? I noticed the stepper had been replaced at some point and i know sometimes (if an aftermarket unit is used) the stepper feedback signal goes all crazy! So gonna try a stepper from a known good machine we are getting in a couple of weeks time. But until then any ideas are welcome guys.

Thanks

 

[digger_hunter]

oh so despite everything we did same story, can't calibrate as we get 70 H 00 and then 70 HF 03. Only times we got SP and once i even got another step forward when we messed around with the governor cables a bit, so thats why i think its the feedback signal from the stepper.

 

[Jeff Ski]

Just curious if you ever figured out what the problem was? I'm having the same issue with my machine. Thanks, Jeff

 

[digger_hunter]

Hi Jeff it was the feedback potentiometer in the stepper motor. So we replaced that.

 

[Jeff Ski]

Thanks. I've replace the gov. and cable and everything was working great and the next day i started the machine and it just right to full throttle and wont turn down no matter what i do. I haven't done a governor recal. yet and im not sure exactly how to do it to be honest. Would you have any advice? I have a 312 serial 6bl00625 if that helps. Thanks!! Jeff