Cause analysis and treatment of Caterpillar excavator's failure to start
If other conditions are completely normal, the failure of the flameout solenoid valve and the starter will cause the excavator to fail to start
1. The flameout solenoid valve does not work: at the moment when the key start switch is turned to the start position, the quick suction coil end of the flameout solenoid valve should have power. After the release reset, the holding coil should have power input, while the quick suction coil has no power; If the input is completely normal and the solenoid valve does not act, the solenoid valve is damaged; If the input is abnormal, please check the corresponding quick start and hold relay;
2. Starter does not work: when the key start switch is turned to the start position, the start (R2) end of the key switch shall have power output. If there is no output, the key switch is damaged; After the starting end of the key switch has output to the starting composite relay, measure whether the starting composite relay has output. There are two reasons for not outputting: 1. The starting composite relay is damaged;
3. There is power supply voltage at the midpoint signal terminal of the starting composite relay (check whether the input of the signal at the midpoint signal terminal is short circuited with the power supply or the output of the starter midpoint is abnormal). If the output of the starting composite relay is normal, check whether the harness connection between the output end of the starting composite relay and the starter is intact (measure whether the starting wire at the starter end has voltage); If the above conditions are completely normal, it can be judged that the starter cannot work normally.
Note: the above judgment can only be established when other conditions are completely normal. If the system voltage is too low, the starter will not start.
