Causes of Failure of Generator Set Fuel Injection Pump Plunger

Dec. 23, 2021

When the plunger of the fuel injection pump of the generator set is issued, it will affect the normal operation of the governor and easily cause the engine to run away. If it is not handled in time, it will cause more serious failures. So, what are the reasons and troubleshooting methods for the injection pump plunger of the generator set?


1. The plunger is bent.

As the plunger and auxiliary parts are not paid attention to during transportation, storage and assembly, the plunger is slightly bent and card issuance occurs during work. If this happens, it should be replaced in time.

2. The plunger is strained.

Since the plunger was not cleaned during assembly, or impurities entered between the plunger pairs, carelessness during assembly caused the plunger to be strained, causing the plunger to get stuck. Therefore, you should install it carefully during assembly, do not damage the plunger, and clean the plunger pair and even parts to reduce the entry of impurities between the plunger pair.

Causes of Failure of Generator Set Fuel Injection Pump Plunger

3. The sleeve positioning screw is too long.

If the positioning screw of the plunger sleeve of generator set is too long or the washer is forgotten when the positioning screw is installed, the sleeve will be crushed and the sleeve will be offset, causing the plunger to get stuck. If the set screw is too long, you can file a proper amount of short, and do not forget to install the washer when installing the set screw.

4. The base of the pump body is not flat.

Because the base of the pump body is installed on the shoulder of the plunger sleeve is uneven or dirty, which affects the assembly accuracy of the sleeve, and makes the assembly of the diesel engine parts oil pump plunger skewed, causing the plunger to get stuck. The method to check the unevenness of the pump body is to pull down the fuel injection pump from the body, connect the low-pressure oil circuit and turn on the fuel tank switch to fill the pump body with diesel oil, and wipe the outside of the fuel injection pump clean. If oil leakage is found at the rollers, it means that the base of the pump body is not flat, causing diesel leakage. You can use an old plunger sleeve, coat the shoulder with abrasive sand, put it into the pump body, rotate and knock the sleeve continuously. After grinding and smoothing, install and reinstall and check for oil leakage.

5. The storage time of the new plunger pair is too long.

The storage time of the new plunger is too long, it is easy to cause oil loss and oxidation reaction, make the plunger rust, assembly without cleaning, causing the plunger to get stuck during work. In this case, the plunger pair must be soaked in kerosene or diesel for a period of time, and then rotate and repeatedly pull the plungers to grind each other until the plunger pair rotates flexibly and carefully cleaned before assembly and use.

What are the common faults of diesel generator set fuel injection pump?

1. The fuel injection pump of the generator set does not inject fuel. The reasons for the failure are: no diesel in the fuel tank; air in the fuel system; blockage of the fuel filter or fuel pipe; failure of the fuel delivery pump and no fuel supply; plunger and even parts Seizure; the joint surface of the oil outlet valve seat and the plunger sleeve is poorly sealed.

Troubleshooting: add diesel oil in time; Loosen the oil drain screws of the oil transfer pump and pump the oil pump by hand to remove the air; Clean the paper filter element or replace it, and blow it clean after cleaning the oil pipe; Repair according to the troubleshooting method of oil transfer pump; Remove the plunger coupling for grinding or replacement; Remove it for grinding, otherwise it shall be replaced.

2. Uneven oil supply. The fault causes are: there is air in the fuel pipe and intermittent oil supply; The oil outlet valve spring is broken; The oil outlet valve seat surface is worn; Plunger spring is broken; Impurities block the plunger; Only the pressure is too small; The adjusting gear is loose.


Elimination method: remove the air by hand pump; Replace the fuel injection pump; Grinding, repair or replacement; Replace the plunger spring of generating set; Clean the plunger impurities of diesel generator set; Check whether the filter screen and fuel filter of the oil inlet joint of the oil transfer pump are blocked, and clean and maintain them on schedule; Align the factory mark and tighten the screws.


3. Insufficient oil output. The fault causes are: oil leakage of oil outlet valve coupling; The filter screen or fuel filter of the oil inlet joint of the oil transfer pump is blocked; Plunger coupling worn; Oil leakage at oil pipe joint


Troubleshooting: grind, repair or replace; Clean the filter screen or core; Replace the plunger coupling with a new one; Retighten or check.

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