Diesel generator Troubleshooting

Symptoms: Nothing turns over on the start command, no engine rotation; the controller may show a fault or stay dark. Likely causes: Flat or failed starting battery; Loose or corroded starter/earth connections; Failed starter motor or solenoid; Controller lockout or open safety. Fixes: Test and charge or replace the battery; clean and tighten terminals; check the charger and charge-alternator output. Isolate the battery first, then clean and torque the starter, battery and earth connections. Test the starter and solenoid; replace if the solenoid clicks but the motor does not turn. Check the controller for an active shutdown (emergency stop, low oil pressure lockout); find the cause before resetting the fault. Prevention: Scheduled battery load tests, clean and torqued connections, weekly test runs, controller fault-log review.

Symptoms: Engine turns over but does not fire, or fires and dies, often after fuel work or a long standstill. Likely causes: Air in the fuel system; No or low fuel / blocked filter; Fuel shut-off solenoid not energising; Cold engine with failed starting aids. Fixes: Bleed the fuel system at the filters and injection pump per the OEM procedure; confirm the lift pump primes. Check tank level and valves; replace clogged fuel filters; clean a fouled strainer. Verify the run/stop shut-off solenoid pulls in on start; check its fuse, wiring and the controller output. Check glow plugs or intake heater and the jacket-water heater; a worn engine with low compression also resists cold starts. Prevention: Clean fuel with scheduled filter changes, fuel polishing on standby tanks, working jacket-water heater, periodic under-load test runs.

Symptoms: Rising coolant temperature, high-temp alarm or shutdown, coolant loss, steam at the radiator. Likely causes: Low coolant or a leak; Blocked radiator or restricted airflow; Failed cooling fan or slipping belt; Faulty thermostat or water pump. Fixes: Let it cool, then check level and pressure-test for leaks; repair hoses, radiator or water pump; refill with the correct coolant mix. Clean the radiator core and clear obstructions; check enclosure louvres and hot-air recirculation. Inspect the fan drive and belt tension; replace a glazed or worn belt; check the viscous or electric fan. Test and replace a stuck thermostat; check the water pump for wear and weep-hole leakage. Prevention: Coolant level and condition checks, radiator core cleaning, belt inspection, adequate ventilation and clear hot-air discharge, alarm testing.

Symptoms: Voltage or frequency drops under load, breaker trips, engine bogs or surges when load is applied. Likely causes: Fuel starvation under load; Clogged air filter or exhaust restriction; Governor or actuator fault; AVR or excitation problem. Fixes: Replace fuel filters; check for a restricted supply line and a weak lift pump; confirm tank draw and vent are clear. Replace the air filter; check for a blocked or collapsed exhaust and high back-pressure. Check the electronic governor, actuator and speed sensor; correct droop/isochronous settings; look for hunting from a sticking actuator. Test the automatic voltage regulator, sensing leads and exciter; replace a failed AVR; check for loose alternator connections. Prevention: Regular under-load or resistive load-bank tests, filter changes, governor and AVR checks, connection-torque audits.