10 fuel injection pump maintenance methods

10 fuel injection pump maintenance methods

In the process of using the fuel injection pump, we will always encounter many problems. Below we mainly introduce the 10-point method of maintaining the injector.

The fuel injection pump 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 of the fuel injection pump and extend its service life. Do the following.

Posted on Mar 26,2020 by Sharon Wen
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 (1) Use diesel and filters well to ensure that the diesel entering the fuel injection pump is highly clean

Generally speaking, the diesel engine’s filtration requirements for diesel fuel are much higher than those of gasoline engines. For use, select a diesel that meets the requirements of the brand, and it must be deposited for at least 48 hours. Strengthen the cleaning and maintenance of the diesel filter, and clean or replace the filter element in time; clean the fuel tank in time according to the operating environment conditions, completely remove the sludge and moisture at the bottom of the fuel tank, and any impurities in the diesel fuel will affect the fuel injection pump plunger and the fuel outlet valve. Severe corrosion or wear caused by couplings and transmission components.

pump

(2) Always check whether the amount of oil in the oil pool of the injection pump and its quality meet the requirements

Before starting the diesel engine, you should check the amount of oil in the fuel injection pump and its quality (except the fuel injection pump that is forcedly lubricated by the engine) to ensure that the amount of oil is sufficient and the quality is good. If the engine oil is deteriorated by mixing with water or diesel, the lighter will cause the early wear of the plunger and the valve assembly, which will cause the diesel engine to be underpowered and difficult to start. In severe cases, the plunger and the valve assembly will be corroded and rusted. Leaks in the oil pump, poor working of the oil outlet valve, wear of the lifter and casing of the oil pump, and damage to the seal ring will all cause diesel oil to leak into the oil pool and dilute the oil. Therefore, it should be replaced in time according to the quality of the oil. When replacing the oil tank, clean the oil tank thoroughly, and remove impurities such as oil sludge from the bottom of the oil tank, otherwise, the oil will deteriorate if it is not used for a long time. The quantity of engine oil must not be too much or too small. Too much fuel in the governor can easily lead to the “speeding” of the diesel engine. Too little fuel will cause poor lubrication. The oil dipstick or oil plane screw shall prevail. In addition, when the diesel engine is not used for a long time, be sure to check whether there are impurities such as water and diesel in the oil in the oil pool of the pump. If necessary, replace it immediately. Otherwise, due to long-term storage, the water can easily cause the plunger and the oil outlet valve. Even the pieces of rust were stuck and scrapped.

(3) Regularly check and adjust the fuel supply advance angle of the injection pump and the fuel supply interval angle of each cylinder

In use, due to the loosening of the coupling bolts of the coupling and the wear of the camshaft and roller body components, the fuel supply advance angle and the fuel supply interval angle of each cylinder often change, which deteriorates the diesel combustion, and the diesel engine is dynamic and economical. Poor performance, at the same time difficult to start, unstable operation, abnormal noise and overheating. In actual use, most drivers pay attention to the inspection and adjustment of the overall fuel advance angle but ignore the inspection and adjustment of the fuel supply interval angle (involving the single pump fuel advance angle adjustment). However, due to the wear of camshafts and roller transmission parts of other cylinders, the fuel supply is not necessarily timing, which will also cause the diesel engine to start difficult, lack power, and run erratically. Therefore, for fuel injection pumps that have been used for a long time, more attention should be paid to the inspection and adjustment of the fuel supply interval angle.

(4) Regularly check and adjust the fuel supply of each cylinder of the fuel injection pump

Due to the wear of the plunger parts and the oil valve parts, the internal leakage of the diesel will reduce or uneven the fuel supply of each cylinder, resulting in difficulty in starting the diesel engine, insufficient power, increased fuel consumption, and unstable operation. Therefore, it is necessary to regularly check and adjust the fuel supply of each cylinder of the fuel injection pump to ensure the power of the diesel engine. In actual use, the amount of fuel supplied to each cylinder can be determined by observing the exhaust of the diesel engine, listening to the sound of the engine, and touching the temperature of the exhaust manifold.

(5) Check the camshaft clearance regularly

The axial clearance of the camshaft of the fuel injection pump is very strict. One is between 0.03 and 0.15mm. If the clearance is too large, it will intensify the impact of the roller transmission components on the cam working surface, thereby increasing the early wear of the cam surface. Change the fuel supply advance angle; the axial and radial clearances of the camshaft bearings are too large, which may cause the camshaft to run erratically, the oil quantity adjustment rods to tremble, the fuel supply amount to change periodically, and the diesel engine to run erratically. And adjust. When the axial clearance of the camshaft is too large, you can add shims on both sides to adjust it; if the radial clearance is too large, you must replace it with a new one.

(6) Regularly check the seal of the oil valve coupler on the machine

The fuel injection pump works for a period of time. By checking the seal of the oil outlet valve, you can make a rough judgment on the wear of the plunger and the working condition of the oil pump, which is helpful to determine the repair and maintenance methods. During the inspection, unscrew the high-pressure oil pipe joints of each cylinder and pump oil with the oil pump’s hand pump. If the oil is found out from the oil pipe joint at the top of the fuel injection pump, it means that the oil outlet valve is poorly sealed (of course, the oil outlet valve spring will also break when it breaks) this circumstance occurs). If the multi-cylinder has a bad seal, the fuel injection pump should be thoroughly debugged and maintained, and the spare parts should be replaced.

(7) Use standard high-pressure tubing

During the fuel injection process of the fuel injection pump, due to the compressibility of diesel oil, high-pressure diesel oil will form pressure fluctuations in the pipe. It takes a certain amount of time for the pressure wave to pass through the tube. In order to ensure that the oil supply interval angle of each cylinder is uniform, the oil supply is uniform, and the diesel engine works smoothly, the length and diameter of the high-pressure oil pipe are selected after calculation. Therefore, when the high-pressure oil pipe of a cylinder is damaged, the oil pipe of standard length and pipe diameter should be replaced. In actual use, due to the lack of standard oil pipes, use other oil pipes instead. If the length and diameter of the oil pipes are not considered, the length and diameter of the oil pipes will be very different. Although it can be used in an emergency, it will cause the supply of the cylinder. The oil advance angle and the amount of oil supply have changed, which makes the whole machine not stable, so be sure to use standard high-pressure oil pipes in use.

(8) Regularly check the wear of related keyways and fixing bolts

The relevant key grooves and bolts mainly refer to camshaft key grooves, convex green key grooves of couplings (oil pumps transmitting power through the couplings), semicircular keys, and coupling fixing bolts. The fuel pump camshaft keyway, convex green keyway, and semi-circular key are worn for a long time, which causes the lighter to wear and widen the keyway. The semi-circular key is not installed securely and the fuel supply advance angle is changed. In the heavy case, the key rolls off, resulting in power transmission failure. Therefore, regular inspections are required to repair or replace worn parts in a timely manner.

(9) Replace worn plungers and oil valve couplers in time

When it is found that the diesel engine is difficult to start, the power is reduced, and the fuel consumption is increased, if the injection pump and the injector are still not improved by adjusting the fuel injection pump plunger and the valve assembly, such as after the plunger and the valve are worn, The losses caused by the difficulty of starting the diesel engine, the increase in fuel consumption, and the lack of power far exceed the cost of replacing the spare parts. After replacement, the power and economy of the diesel engine will be significantly improved. Therefore, the worn-out spare parts must be replaced in time.

(10) Correctly maintain the accessories of the fuel injection pump

The side cover of the pump body, dipstick, filler plug (breather), oil spill valve, oil pool plug, oil level screw, oil pump fixing bolt, etc., must be intact. These accessories are essential to the work of the fuel injection pump. Important role. For example, the side cover can prevent the invasion of dust, moisture, and other impurities, the respirator (with filter) can effectively prevent the deterioration of the oil, and the oil spill valve ensures that the fuel system has a certain pressure without entering the air. Therefore, it is necessary to strengthen the maintenance of these accessories, and if they are found to be damaged or missing, they must be repaired or replaced in time.

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