In the middle of a rush construction schedule, your excavator suddenly breaks down? Whether it’s failure to start, weak hydraulic power, or stuck travel—don’t panic! These 4 common fault diagnosis guides will help you quickly locate problems, reduce downtime losses.
- Electrical System Faults: Instrument Panel Alarms/Light Malfunctions
Typical Scenario: Fault codes appear on the instrument panel (e.g., engine fault light, hydraulic alarm light), work lights don’t turn on, and windshield wipers don’t work.
Core Causes + Troubleshooting Steps:
• First, check the fuses: Open the electrical box and find the fuse corresponding to the function according to the manual. If blown, replace it with a fuse of the same specification (do not use a larger specification to avoid burning the circuit).
• Next, check the sensors: Common alarms are mostly related to sensors, such as water temperature sensors and oil pressure sensors. Check if the sensor wires are loose and use a multimeter to test if the resistance is within the standard range.
• Be alert to aging wires: Long-term vibration can cause wire damage and short circuits. Focus on checking the wire connectors in the engine compartment and under the cab. Wrap damaged parts with insulating tape and replace the wires if severely damaged. - Difficult to Start the Engine / Stalls After Starting
Typical Scenario: No response when turning the key to the end, or the engine stalls within seconds after starting, and repeated attempts don’t work.
Core Causes + Troubleshooting Steps:
• First, check the “fuel supply” Is the fuel gauge showing normal? Open the fuel tank cap and smell for any spoiled odor. Check if the fuel filter is clogged (especially in rainy seasons, diesel is prone to water ingress and emulsification). You can open the drain valve at the bottom of the filter to check for water accumulation.
• Next, check the “power”: Do the instrument panel lights dim when starting? Listen to the horn—does it sound loud and clear? If the sound is weak, it’s most likely a dead battery or loose terminal posts. Tighten the terminals with a wrench, and call for emergency jump-starting if the battery is dead.
• Finally, inspect the “fuel line”: If the above are normal, the fuel line may be leaking air. Loosen the hand pump and press it—if it feels empty and soft without resistance, you need to check the sealing gaskets at the line connections section by section. Replace damaged parts and bleed the air again. - Weak Hydraulic System, Slow Bucket Lifting/Excavating
Typical Scenario: The bucket “can’t dig into” hard soil, the lifting speed is half as slow as usual, or even settlement occurs.
Core Causes + Troubleshooting Steps:
• Prioritize checking hydraulic oil: Observe if the oil level is below the scale line and if the oil is turbid and black (normal is light yellow). If severely contaminated, replace the hydraulic oil and filter immediately to avoid wearing the hydraulic pump.
• Next, check the pressure value: Start the machine and operate the control lever, then use a pressure gauge to test the pressure of the main safety valve. If it’s lower than the standard value, the safety valve may be worn and require professional adjustment or replacement.
• Be alert to leakage points: Check if there are oil stains on hydraulic cylinders and pipeline joints. Aging seals are a common cause. Replace them promptly when leakage is found to prevent further hydraulic oil loss. - Travel System Faults: Deviation/Stuttering
Typical Scenario: Deviates to one side when traveling straight, stutters and makes abnormal noises when turning, or one side of the track doesn’t move.
Core Causes + Troubleshooting Steps:
• First, check the track condition: Are there stones or branches stuck in the track plates? Are the carrier rollers and idlers loose or stuck? Use a crowbar to move them and check flexibility. Clean foreign objects promptly and add lubricating oil.
• Next, check the travel motor: Touch the outer shell of the travel motor—if it gets hot quickly after starting, the motor may have internal wear or insufficient hydraulic oil. Stop the machine to check if the motor oil seal is leaking; disassemble and repair if necessary.
• Finally, inspect the control valve: If there’s an obvious power difference between the two tracks, the spool of the travel control valve may be stuck. Try operating the lever repeatedly to free the spool; if ineffective, disassemble and clean it.
Veteran Operator’s Reminder
- Do the “three checks” daily: Check the oil level before work, check the temperature during work, and check for leaks after work—this can reduce 80% of sudden faults;
- Don’t randomly clear fault codes! Take photos to record the fault cod.
- Don’t disassemble core components (hydraulic pump, engine) by yourself. It’s more reliable to find a qualified maintenance team.
