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Why Does Fuel Injection Pump of Electric Generator not Supply Oil?

Jun. 24, 2020

Electric generator fuel supply and its speed control system mainly includes fuel injection pump, fuel injector, fuel delivery pump and regulator, etc. No matter which of the above components fails, the unit will not work normally.

Today Starlight generator manufacturer shares the reason why fuel injection pump not supply oil. Hope it is helpful to you.

Why does fuel injection pump of electric generators not supply oil?

1.There is no fuel in fuel tank or the oil switch did not open.

2.Fuel filter is blocked up.

3.There is a lot of air in the oil way.

4.Fuel injection pump plunger spring is broken.

5.Excessive wear of plunger coupling (plunger and plunger sleeve).

6.Plunger is stuck.

7.The position of the screw groove of the plunger is wrong.

8.The oil outlet valve is excessively worn or the oil outlet valve is covered with dirt.

9.The plane contact between the oil outlet valve and the plunger sleeve is not tight (if there is any impurity), which causes the diesel to leak out from the gap of the contact surface, and the fuel injection pump does not supply oil because the oil valve is not pushed out.

10.Oil outlet valve pad is broken.


PS: If all cylinders do not supply oil, the diesel engine will not work at all. If the individual cylinder does not supply oil, it is difficult for the diesel engine to start, that is to say, it starts and works unevenly.

 power generating sets

How to deal with the problem?

1.After finding the fault, first check whether there is fuel in the fuel tank, whether the tank switch is open, and whether the air vent of the tank is blocked.

2.If there is air bubble in the diesel oil flowing out of the vent screw, it indicates that the air has leaked into the oil circuit. The cause should be found out, which is caused by the shortage of diesel oil in the oil tank or the loosening of the oil pipe joint or the rupture of the oil pipe and the untight sealing gasket.

3.After troubleshooting, continue to pump oil by hand pump or gravity flow by diesel until there is no bubble in the diesel. Then tighten the bleed screw and hand oil pump. If the oil supply is not smooth, it means that the low-pressure oil circuit is blocked.

4.Check whether the fuel filter and the low-pressure oil circuit are blocked; if there is oil leakage in the low-pressure oil circuit, it will cause the oil to be blocked.

5.If there is no problem with the delivery pump, the problem is with the injection pump. For the combined fuel injection pump, at this time, the side cover of the fuel injection pump can be removed, the throttle handle can be placed at the stop oil supply position, the plunger spring seat of the fuel injection pump can be pried with a screwdriver, and the pump oil action can be done to check whether the plunger spring is broken and whether the plunger is stuck. At the same time, it is also necessary to check whether the screw of adjusting ring gear is loose, which will cause the change of oil supply. If they are all in good condition, then it is necessary to check the wear degree of the plunger coupling and the tightness of the oil outlet valve.


How to maintain the fuel injector pump of diesel generator set?

1.Use good quality diesel oil and filter to ensure that the diesel oil entering the injection pump is highly clean.

2.Always check whether the oil quantity and quality in the oil pool of the injection pump meet the requirements.

3.Regularly check and adjust the fuel supply advance angle and oil supply interval angle of each cylinder.

4.Regularly check and adjust the oil supply quantity of each cylinder of injection pump.

5.Check the camshaft clearance regularly.

6.Check the sealing condition of the valve coupling regularly.

7.Use standard high pressure tubing.

8.Regularly check the wear of relevant keyway and fixing bolt.

9.Replace the worn plunger and outlet valve coupling in time.

10.To maintain the accessories of the injection pump correctly.


The fuel injection pump of the diesel generator set is an important part of the fuel supply system of the diesel engine. Its working condition directly affects the power, economy and reliability of the diesel engine. Correct maintenance is an important prerequisite to ensure the normal operation and prolong the service life of fuel injection pump.

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