Why Diesel Generator Fail to Start

After using a diesel generator for a long time, some malfunctions may occur that will cause the generator fail to start. What can you do when it happens?

If diesel generators fail to start, you can analyze the causes from fuel system failure, electric starting system failure, insufficient compression pressure in the cylinder and the low ambient temperature and other factors.

Fuel System Failure

1. Air in the fuel system

This is a common problem that a diesel generator fails to start normally.

Solution: Check whether the fuel oil pipe connector is loose or not, and ensure that the air is cleared from the fuel system. Loosen the bleed screw bolt on the diesel filter, and then use the manual oil pump to pump the fuel until the air bubble is gone.

2. Fuel Line Obstruction

Solution: Check whether the pipeline is smooth or not.

3. Fuel Filter Clogging

Solution: Clean the filter or replace the filter element

4. The Handle Position of Fuel Injection Pump Is Not Correct

Solution: The handle position should be pushed to no-load when starting the diesel generator set. Rotation speed is about 700-900r/min.

5. Fuel Injector Problem – Little fuel injection or fuel injection is not atomized   

Solution: Remove the fuel injector, connect it to the high pressure oil pump, pry the fuel injection pump plunger spring and observe the spray condition. If necessary, wash the injection pump.

6. Oil Supply Problem – Oil transfer pump doesn’t supply oil or the oil supply is brokenly.

Solution: Check whether the oil inlet pipe is leaked or not and the filter screen on the oil inlet pipe connector is blocked or not.

Electric Starting System Failure

1. Battery Power Shortage

The most common failure for diesel generator is battery failure.

Solution: Use the battery with sufficient power, or increase the battery to use in parallel. Replace the new start-up battery if necessary.

2. Circuit Wiring Error or Poor Contact

Solution: Check whether the wiring is correct and reliable.

The compression pressure in the cylinder is insufficient; fuel injection is normal but does not catch fire; or fuel oil inside the exhaust pipe

1. Excessive wear of piston ring and cylinder liner

Solution: Replace the piston ring, and replace the cylinder liner according to the wear condition.

2. Valve leakage

Solution: Check the valve clearance, vlave spring,  as well as  the sealing of the valve guide and seat. If the seal is not good, you should make a repair.

3. Combustion chamber volume is too large

Solution: Check whether the piston belongs to the model, if necessary, measure the combustion chamber volume.

Ambient Temperature Is Low

Solution: According to the actual ambient temperature, the corresponding low temperature measures should be adopted.

A lack of diesel generator maintenance or operation knowledge will undoubtedly result in malfunction. To prevent the malfunction occurring again, it is obvious that daily maintenance of the generating set is very important, which not only helps prolong the service life of the machine, but also reduces the cost. If you want to know more manintenance tips for the diesel generator, the following articles will be helpful.

Useful Maintenance Tips for Diesel Generator Set

Maintenance Tips for Diesel Engine

Daily Maintenance for a Generator