Steps for maintain the fuel injection pump of diesel engine

Fuel injection pump is an important component of fuel supply system in diesel engine, so its working status affect diesel engine reliably, economically and dynamically. Correct maintenance is an important precondition to insure injection pump working normally and extend its lifetime. So here we listed ten steps summed up from our experiences for your reference.

1、To monitor filtering process strictly to ensure the diesel going into injection pump is highly clean.

General speaking, diesel filtering is more strict than gasoline filtering process, so we must choose one brand which is suitable for requests and deposit at least 48hrs. strengthening maintenance and cleaning of diesel filter, replacement or cleaning timely；Washing fuel tank and removing the fuel deposit and water according to working condition, any impurity in diesel will cause pump jam and abrasion or corrosion of driving parts and fuel valve.

2、To check the oil quality and level of oil pool often

It is necessary to check oil level and quality of oil in injection pump every time we start generator sets except that engine forced lubrication, if oil goes bad by mixing with water, the lighter aftermath will cause jams and abrasion of oil vavle and lower power of engine and starting hardly. The heavier aftermath is to corrode oil valve. Meanwhile those problems like inner leakage of pump, oil valve working status and sealing ring breakage will let diesel go into oil for dilution, so it becomes very important to replace oil and wash oil pool wholly and remove impurities like oil deposit in order to avoid oil going bad again.

3、To regularly examine and adjust the fuel supply advance angle of fuel injection pump and oil supply interval angle of each cylinder.

Loose coupling bolts and abrasion of camshaft and rollers often lead to change of fuel supply advance angle and the cylinder oil interval angle, which make diesel go bad, accordingly causing deterioration of diesel combustion and economic nature, difficulty in starting, instable running, abnormal noise and overheat etc.. in practice most people only examine and adjust the overall fuel supply advance angle, but ignore examination and adjustment of the oil interval angle (involving adjustment of a single pump fuel supply advance angle ), doing that benefits fuel supply timely in first cylinder, but it is hard to ensure fuel supply timely in other cylinders because of arbasion of camshaft and roller components , so that difficult starting-up, power shortage and running unsmoothly, so it is very important to examine and adjust interval angle, especially for those used for long time.

4、To examine and adjust oil supply of each cylinder periodically.

Fuel leakage caused by abrasion of plunger and coupling valve will reduce oil supply or unevenly. Accordingly causing difficulty in starting, power shortage, increased fuel consumption and instable operation. Therefore, we should regularly examine and adjust the oil supply volume of each cylinder to ensure engine work effectively. In practice, we can determine oil supply volume of each cylider by observing the diesel smoke, listening to the engine noise and touching exhaust manifold temperature.

5、To exmaine clearance of camshaft regularly.

Axial clearance of camshaft is controlled between 0.03～0.15mm strictly, if the gap is too large, it will aggravate the impact of the work surface imposed by driving components,thereby increasing the early abrasion of cam surface and changing Oil advance angle; another hand, if the gas is too large, it could aslo lead to camshaft operating unsmoothly and fuel adjustment rod jitter,accompanying problems like periodic changes in fuel supply so that engine operation is unstable, therefore we should regularly examine and adjust clearance of camshaft. If axial clearance of camshaft is too large, we can add the pads on both sides to adjust it, if the radial clearance is too large, we usually need to replace a new one.

6、To examine the seal condition of coupling parts of outlet valve regularly.

We can make rough judgements on abrasion of plunger and working status of pump by checking seal condition of outlet oil vavle. Which will help determine the method of repair and maintenance. when inspection, We should twist the high-pressure oil pipe joints of each cylinder and use hand pump to pump oil, if we found that there was oil outlet at the top of the pipeline joints, it proves that the seal of outlet valve is not good, (of course a broken valve spring will cause same problem), if multi-cylinders have same problem, then a thorough commissioning and maintenance should be conducted, or even replacement of coupling parts.

7、To use standard high-pressure oil pipeline

high-pressure diesel will be the formation of pressure fluctuation in the pipe during fuel supply process due to the compressibility of diesel and flexibility of high-pressure oil pipeline, and the pressure wave in the pipe will take some time to pass, the length and diameter of high-pressure pipeline are measured and selected in order to ensure oil supply interval angle of each cylinder unanimously and fuel supply evenly and diesel engine working steadily, Thus, when one high-pressure pipeline is damaged, we should replace it by standard one. In actual use, we usually don’t consider length and diameter of pipeline so that there are big differences between length and diameter, although it can be as emergency use, but it will change oil supply advance angle and volume of oil supply so that the whole machine work instably, so we must use standard high-pressure pipeline.

8、To examine abrasion condition of relevant keyway and fixed bolts.

Related keyway and bolts mainly refer to the camshaft keyway, coupling flange keyway (oil pump to use coupling to transfer power ), semi-circular keys as well as coupling fixed bolts. due to long-term usage of camshaft keyway of injection pump and flange keyway and semi-circular key, the lighter aftermath is abrasion and keyway boardening and semi-circular keway installation insecurely and change of fuel supply advance angle; the severer case is key sub-rolled, resulting in power transfer failure, therefore we should regularly check, repair and replace worn parts.

9、To replace worn plungers and coupling parts of oil outlet valve timely

When we found problems like difficulty in starting diesel engines, power down and fuel consumption increased, we should dismantle plunger of injection pump and coupling parts of oil outlet valve if it can not be improved by by adjusting the fuel pump and injector, they should be promptly replaced if plunger and outlet valve are worn to a certain level, and do not insist on using any more.

10、To maintain accessories of injection pump in right way.

We must ensure Pump side covers, oil-foot, fuel plug (respirator), oil spill valve, oil tank screw block, oil flat screws, oil pump bolts intactly, these accessories play very important role in work performance of injection pump, eg. the side cover prevent intrusion of dust, moisture and other impurities, respirator (with filter) can effectively prevent oil deterioration, oil spill valve ensure the fuel system has a certain pressure to stop air going into. therefore we must strengthen maintenance of these accessories, and it must be promptly reparied or replaced once we discovered damage or loss.