As a well-known Sino-American joint venture in the power equipment industry, Cummins diesel generator sets are widely favored in the industrial sector for their easy maintenance, strong economic performance, and excellent load response characteristics. To help users better manage equipment operation and maintenance challenges, we have summarized four common operational faults and key troubleshooting steps as follows:
1. Difficult Starting – Troubleshooting Procedure
When the equipment fails to start normally, it is recommended to follow a three-level diagnostic approach:
- Energy System Check:
First, check the battery charge (voltage ≥ 24V) and electrolyte specific gravity (standard value: 1.28 g/cm³). Also, verify the fuel tank level (recommended to maintain at least 90% capacity). - Power Transmission Test:
Use a pressure gauge to measure the fuel pump output pressure (normal range: 0.25–0.35 MPa), and simultaneously check the pulsation frequency of the high-pressure fuel pipe. - Mechanical Connection Inspection:
Focus on inspecting the flywheel housing bolts (torque should meet the 280–320 N·m standard) and the engine mount tightening condition.
2. Frequency Fluctuation – Diagnostic Guidelines
When frequency instability occurs, proceed with the following diagnostic steps:
- Electrical Parameter Check:
Use a multimeter to measure the output voltage fluctuation range (allowable deviation: ±1%) and record the fluctuation cycle. - Governing System Inspection:
Dismantle and inspect the Electronic Speed Governor (EST) module, focusing on PID parameter settings (typical values: P = 4, I = 0.3, D = 0.5). - Fuel System Troubleshooting:
Use a transparent fuel line observation method to check the low-pressure fuel line for air bubbles (bubble content should be less than 5% of the pipe diameter).
3. Unexpected Shutdown – Fault Analysis
If the unit shuts down due to protection mechanisms while oil pressure appears normal, the following components should be checked:
- Sensor System:
Use a pressure calibrator to test the oil pressure switch (typical action value: 0.15 MPa ± 0.02). - Control Unit:
Retrieve controller fault codes via the HMI interface (pay special attention to 1681/1682 series codes). - Wiring Inspection:
Measure the insulation resistance of the control circuit (standard value: >2 MΩ) and check for connector oxidation.
4. Black Smoke Emission – Troubleshooting Strategy
When abnormal black smoke emissions occur, a tiered diagnostic method is recommended:
- Boost System Inspection:
Measure turbocharger speed (should reach 120,000 rpm ± 5% under rated conditions), and check intercooler pressure drop (acceptable value: <5 kPa). - Injection System Calibration:
Use an injector test bench to check the injection start pressure (standard value: 25 MPa ± 0.5), and observe the atomization spray cone angle (recommended: 110°–120°). - Combustion Chamber Check:
Use an endoscope to inspect piston crown carbon deposits (deposit area should be <30%), and measure cylinder pressure (normal range: 2.8–3.2 MPa).