Hi All, Would anyone have a wiring schematic for a Zx80-1 throttle control circuit? Machine is throttling down during use, often when boom cylinder is extended fully but not always. Have replaced EC sensor but machine is not quite right after learning procedure is done. Engine revs too high at start up. Then after running a while and particularly if she is put into P mode and and turned back to E mode the tick over revs are a little low. Any suggestions greatly appreciated. Thank you.
The learning procedure sometimes isn't easy to get right. I've seen myself replacing main controllers and stepper motors and still have quite erratic idle speeds but I just try and get it as good as I can then leave it at that. I'll give you a step by step procedure 1 Check the cable and linkages and make sure there's no play in the linkage or tight cables 2 Warm the engine up fully. This is necessary because the idle speed will rise slightly when the engine is cold. 3 carry out learning using the switch in the cab. 4 Confirm that the signal wire from the EC sensor is set at 2.5v. If it is, run the engine and unplug the 4 pin connector on the stepper motor 5 Using a tachometer, measure the engine rpm, and set the low idle speed by loosening the lever on the shaft of the motor and moving the linkage back and forth to get the desired speed. 6 plug the 4 pin connector back in then run the engine at various engine speeds to see if it achieves maximum speed
ZX80-1 low idle spec is 1050-1200 rpm.
Thank you for the replies. 2 things I'm unclear on: 1)Voltage from the EC sensor set at 2.5v, how do you check this? I can measure voltage on the connector when separated but this is voltage from the controller to the sensor and is currently measuring 3.2V at idle. 2) Is learning done with linkage connected ? I would have thought the linkage should be disconnected to let the sensor find 2.5V and then adjust the lever arm on the motor to set idle rpm. Thanks
You can check the EC sensor angle voltage when monitor is in “service mode“ To get into a Deere C series or Hitachi ZX -1 excavator service mode, press and hold the set button then key on or start. After bulb check release the button. Then use the select button to scroll. . The service mode available data list on 80C or 80ZX-1 is quite short compared to excavators 120C ,ZX110/120 and larger. See data list for the small excavators below .
See 2 screenshots of the learning procedure from the manual below. .
Thank you for the information. Machine is going out on a job for a few days so I will look into all this when it is back in the yard.