DIY repair of fuel pump mtz diesel engines

Malfunctions of the fuel pump TNVD UTN-5 engine D-240

During the operation of the D-240 diesel engine of the MTZ-80, MTZ-82 tractors, the following malfunctions of the fuel equipment may appear: the diesel does not start, does not develop normal power, it works unstably, the work is accompanied by a smoke release.

To ensure a clear start of the diesel engine, the crankshaft is given a sufficient rotation speed, and the air in the cylinders at this time is compressed so that, at the time of fuel injection, the temperature is sufficient to ignite it, so that the fuel is supplied to the combustion chamber in a timely manner, in sufficient quantity and finely atomized.

The fuel supply can be disrupted for various reasons, the formation of air plugs in the fuel lines, in the head of the fuel injection pump UTN-5, in the filters; severe wear of plunger pairs of pumping elements of the pump, spray nozzles; violation of the regulation of the fuel pump or its incorrect installation on a diesel engine.

The appearance of black or gray smoke from the exhaust pipe of a diesel engine indicates that oil has entered the combustion chamber, incomplete combustion of fuel, misfiring of flashes in the cylinders, incorrect setting of the start of fuel delivery by the fuel pump.

The ingress of oil into the combustion chamber can be explained by the extreme wear of the piston group of the MMZ D-240 engine, an excess of oil in the oil pan. Incomplete combustion can be caused by both an excess portion of fuel entering the cylinder and a lack of air.

It is observed with poor fuel atomization by UTN-5 nozzles, the use of an inappropriate fuel grade, with late fuel injection into the diesel cylinders.

An external sign of deterioration in the operation of the D-240 injectors is a smoke exhaust, interruptions in operation and a decrease in diesel power. To check the injectors, a diesel engine is set to operate in such a way that interruptions are most clearly audible. Then, alternately loosen the union nuts securing the fuel lines of the injectors to the fittings.

If the crankshaft speed does not change after loosening the nut, then the tested injector is faulty. If the lift pressure of the injector needle (injection pressure) is less than normal due to a change in spring stiffness or leaks in the liner-plunger interface, then the fuel injection time will increase and the atomization quality will be poor.

When the needle lift pressure is greater than normal or the needle sticks in the lower position, the duration of injection and the amount of fuel decrease, which also affects the starting qualities of the diesel engine.

The D-240 fuel pump injectors are removed from the diesel engine and adjusted on the device. The injection pressure and tightness of the injectors can be determined without removing them from the diesel engine. For this, a device and an autostethoscope are used. The device is connected to the tested injector and a forced fuel supply is created by the handle. The injection pressure is set by rotating the injector screw.

If the pressure is not regulated, this indicates a stuck needle in the gun body. The quality of spraying is judged by the characteristic click heard through the autostethoscope, which indicates a clear fit of the needle into the seat of the atomizer at the moment of the end of the injection.

Difficulty starting a diesel engine can be caused by the presence of water in the fuel, a drop in air temperature at the end of compression, which is not enough to ignite the fuel.

A decrease in the temperature of compressed air is usually caused by a decrease in pressure at the end of compression due to air leaks through leaks in the piston (with wear or coking of the piston rings, wear of liners and pistons, valve timing, etc.). The same phenomena are observed when the air cleaner becomes clogged, when the amount of air entering the cylinders decreases.

With a decrease in the ambient air temperature, the crankshaft speed at start-up decreases, due to thickening of the crankcase oil, air leaks through various leaks grow, the temperature of the end of air compression decreases due to heat transfer to the cold walls of cylinders, pistons and combustion chambers.

Diesel D-240 MMZ can be difficult to start due to violation of the adjustment of the advance angle of the start of fuel supply, wear of the plunger pairs of the high pressure fuel pump.

The amount of fuel supplied to the cylinders and the precise operation of the MTZ-80, MTZ-82 engine injectors are interrelated with the deterioration of the plunger pairs of the UTN-5 injection pump.

The technical condition of the plunger pairs is checked with a device that determines the pressure developed by the plunger pairs of the pump at starting speed. The device is connected to the unions of the pumping sections of the fuel pump. Diesel is scrolled with a starting device.

If the developed pressure is at least 30 MPa, then the plunger pair is in good order. The tightness of the discharge valve is checked by the time the pressure drops from 15 to 10 MPa in at least 10 s. If the readings of the pressure gauge of the device are below the given parameters, the fuel pump of the injection pump UTN-5 must be repaired.

The operation of the MMZ D-240 diesel engine without load with the emission of gray smoke from the exhaust pipe, and with an increase in the load - black smoke, indicates a late supply of fuel to the cylinders. The "hard" operation of the diesel engine is accompanied by sharp knocks, and the emission of black smoke from the exhaust pipe with increasing load indicates an early supply of fuel to the cylinders.

The moment of the beginning of the fuel supply by the sections, by which the angle of the beginning of fuel injection into the cylinders is judged, is one of the important parameters that affect not only the power and economic indicators, but also the starting qualities of the diesel engine.

During long-term operation of the MTZ-80, MTZ-82 tractor, the moment of fuel supply may change as the plunger pairs wear out, therefore from time to time it is controlled with the KI-4941 device.

The change in the moment of fuel supply during operation is explained by the fact that with worn-out plunger pairs of the fuel pump, if you slowly turn the crankshaft, part of the fuel, due to the high stiffness of the pressure valve spring, will leak into the gap between the plunger and the liner, and the pressure valve will open later than with new plunger pairs.

The rigidity of the technological spring of the device is eight to ten times less than the rigidity of the pressure valve spring, and therefore fuel is supplied with any degree of wear of the plunger pair, due to which the valve opens at the moment of overlap of the supra-plunger space. For UTN-5 pumps, the fuel supply in idle mode is regulated by changing the number of working turns of the regulator spring.

To reduce the fuel supply and the corresponding decrease in the frequency of complete shutdown of the fuel supply, the number of spring turns is increased, and to increase it, it is reduced.

Check the fuel supply at the maximum torque mode (overload mode), changing it in this mode by adjusting the corrector. To increase the fuel supply, the corrector is screwed in or the spring force is changed.

The corrector is adjusted before installing it in the regulator of the UTN-5 fuel pump. Its stroke should be 1.3. 1.5 mm. It is installed using spacers. The compression force of the corrector spring is 85. 90 for the pumps of MMZ D-240 diesel engines. It is measured when the corrector rod is flush with the body.

The starting fuel supply should be 14.5 cm3 per 100 cycles at a camshaft speed of 150 min1. Set the regulator control lever to the maximum feed position and the amount of rack displacement by the regulator in the direction of increasing the fuel supply using the power lever bolt. The final operation to adjust the pumps is to set the regulator lever to completely shut off the flow.

The starting frequency of rotation of the camshaft of the pump is set, the lever of the regulator is moved to the stop in the screw "Stop" and the fuel is monitored from the injectors. Feeding should stop.

Otherwise, unscrew the screw before stopping the feed. With a decrease in the hydraulic density of precision parts (the appearance of fuel leaks in their interfaces), the pumping element assembly is replaced and at the same time the state of the discharge valve is monitored.

To replace the pumping elements, the fuel pump of the MTZ-80, MTZ-82 tractor is partially disassembled. At the UTN-5 injection pump, open the regulator cover, disconnect the intermediate lever rod from the rail, unscrew the fastening bolts and remove the assembled regulator. Then check the amount of axial movement of the camshaft.

Axial movement should be no more than 0.2 mm. At the same time, the axial movement of the weight coupling is checked. Its significant movement leads to spontaneous movement of the rack, which causes unstable operation of the diesel engine.

When replacing the pumping element, the hatch of the D-240 fuel injection pump housing is removed, the dowel pin fixing its sleeve is removed, and then, using the device, the discharge valve assembly with a seat is removed. To remove the pusher spring, the spring support plate is removed, and the pumping element is removed through the hole in the UTN-5 pump head.

When installing new pumping elements, the slot on the ring gear must coincide with the slot on the sleeve, and the mark on the plunger shank must face the pump housing hatch. When installing the gear rims, the pump rack is installed so that the end face of its driver is at a distance of 24.25 mm from the plane of the pump.

Diesel injectors D-240

The technical condition of the MTZ-80, MTZ-82 nozzles significantly affects the operation of the D-240 tractor diesel engine; the operation of the diesel engine is observed intermittently, its start-up is difficult, etc. In general, nozzles with pinless atomizers, multi-hole, are used. The main malfunctions of the nozzles: wear or freezing (coking) of the nozzles, insufficient fuel injection pressure, poor-quality spray.

If, when checking on the device, one of the above defects is found, the nozzle is disassembled in order to replace the atomizer body with the needle assembly. To disassemble the nozzle, it is installed in a device or clamped in a vice and the sprayer nuts and springs are unscrewed. A new atomizer is installed and a control check of the injector performance is carried out.

When selecting a spray nozzle, carefully examine its marking and design. Externally, the nozzles are similar to each other, however, in design, they have significant differences in the number of spray holes and their size. Residues of carbon and tarry deposits from the outer surfaces are removed with a brass wire brush and rinsed in gasoline.

The atomizer is replaced if its surface has cracks, chips and breaks of any size, and the needle hangs in the body. In the absence of new sprayers, the D-240 injector can be restored to its proper working capacity by carrying out simple repairs.

When the holes of the sprayer are coked, the needle is removed from it, and the spray holes are cleaned with a magnetized drill or wire. In case of partial loss of tightness (hanging of the needle or insignificant appearance of smudges on the sprayer when testing the nozzle), the surfaces of the housing and the sprayer needle are “refreshed”.

For this, the needle is clamped in the drill chuck, and it is installed in the spindle of the lathe, setting the rotational speed to 150.200 min-1. A thin layer of aluminum oxide paste is applied to the cylindrical surface and joint grinding of the body and the needle is carried out until an even shine is obtained over the entire surface.

Next, rub the locking cones and the spray needle. A thin layer of paste is applied to the cone and the conical surfaces are rubbed until a sealing band is formed at the end of the needle, located at the base of the locking cone. The width of the belt should be 0.5. 0.7 mm.

At the same time, the end surfaces of the nozzle body and the sprayer are "refreshed". Remove the pins from the nozzle body, apply a layer of paste to the lapping plate and polish the end of the body until an even shine is obtained. After cleaning and lapping work, all parts are washed in gasoline and wiped thoroughly.

After installing and tightening the nozzle nut of the D-240 internal combustion engine nozzle, check the ease of the needle stroke. To do this, shake the nozzle. The spray needle should hit the body. The torque of the gun nut is 0.7. 0.8 Nm, nozzle cap 0.8. 1.0 Nm. The final step is to check the density of the atomizer.

The pressure is set according to the pressure gauge of the device 30. 31 MPa and the time of pressure drop (density) is determined from 28 to 23 MPa. It should be at least 10 s for new nozzles, and 3 s for used ones.

When checking the density, fuel leakage through the nozzle holes is not allowed. The minimum density characterizes the maximum clearance between the nozzle body and the needle in its cylindrical part. The minimum gap diameter in this part of the nozzle is 1.2 µm.

If the density is unsatisfactory, the end surfaces of the nozzle and sprayer bodies of the MTZ-80, MTZ-82 tractor are refreshed. If, after that, the required density is not reached, the nebulizer assembly is replaced. At normal density, the injectors regulate the operating pressure at the start of injection.

After assembling and testing the D-240 injectors, they are checked for throughput. The injectors selected for a set for operation on one diesel engine should not differ in capacity by more than 4% from the average value of the capacity of the entire set of injectors.

To check this parameter, the injectors are installed on a test bench and the flow rate of each nozzle is determined for 1000 cycles at the nominal rotational speed of the camshaft of the UTN-5 fuel pump.

What are the main signs of malfunctions of the fuel equipment of the MTZ-80, MTZ-82 tractor? It happens that the diesel does not start, does not develop normal power, or is unstable. Sometimes works with the appearance of a smoky release.

All these malfunctions are largely due to a violation of the fuel supply. Why could this be? Air locks may form in the fuel lines, fuel pump head, filters. A strong production of plunger pairs of the fuel pump, injector nozzles is also possible. And it also happens that the adjustment of the fuel pump is violated or, in general, its incorrect installation on the engine.

If you notice that black or gray smoke appears from the exhaust pipe of the engine, then this may mean that incomplete combustion of fuel occurs, that there are skips of flashes in the cylinders. An error in the beginning of the fuel supply by the fuel pump is also possible.

Underburning of fuel can be explained by both its excess and lack of air mixture. This also happens when using fuel of inappropriate quality, as well as late fuel injection into the engine cylinders.

Observing from the outside, the deterioration of the injectors is manifested in smoke exhaust, interruptions in operation and a decrease in engine thrust.

How will the injectors be checked? To do this, select a mode of engine operation in which interruptions are clearly audible.Then, one by one, loosen the union nuts for fixing the fuel lines of the injectors to the unions of the fuel pump. A constant crankshaft speed after loosening the nut tightening indicates a malfunction of the injector under test. An increase in the fuel injection time, a decrease in the quality of its atomization can occur for the following reasons: a decrease in the lifting pressure of the nozzle needle due to a weakening of the spring stiffness or the appearance of leaks in the liner-plunger ligament. When the needle lift is pressed more than the standard one or the needle is jammed in the lower position, the injection time and the amount of fuel delivered to the cylinder will decrease. This, of course, also affects the starting properties of the engine.

The injectors are dismantled and adjusted using the KI-562, KI-3333 or KI-15706 device for an injection pressure of 17.8-18.5 MPa.

Injection pressure and injector tightness can be calculated directly on the engine. To do this, use the KI-16301A device and an autostethoscope (Fig. 2.1.52).

Rice. 2.1.52. How to determine the injection pressure and tightness of the nozzle of the MTZ-80, MTZ-82 tractor:
1 - nozzle; 2 - device KI-163101A

First, the high-pressure fuel line is separated, and a forced supply of fuel is realized with the handle. Then the device is connected to the nozzle of interest. The required injection pressure is set by turning the nozzle screw. If the correct pressure is not controlled, then the needle in the sprayer body is stuck. You can talk about the quality of spraying if you hear a characteristic click. It can be heard with an autostethoscope. The click is heard only when the needle is clearly seated in the nozzle seat during the period when the injection is completed.

A splash of coolant from the radiator vapor pipe indicates a violation of the nozzle cup seals, breakdown and cracks in the cylinder head.

The nozzle glass is removed from the block head, but first the M24X2.0 thread is cut on the inner surface of the glass using a special device. How to place the device, see fig. 2.1.53-2.1.55.

Rice. 2.1.53. How to unscrew the nut that secures the nozzle cup MTZ-80, MTZ-82:
1 key;
2 - cup fastening nut;
3 - cylinder head

Rice. 2.1.54. How to cut a thread in a nozzle glass MTZ-80, MTZ-82:
1 - cylinder head;
2 - nozzle glass;
3 - tap М24 × 2.0

Rice. 2.1.55. How to press out the nozzle glass from the MTZ-80, MTZ-82 cylinder heads:
1 - a device for pressing out the nozzle glass;
2 - nozzle glass;
3 - cylinder head

If the engine is difficult to start, water may have entered the fuel. Due to the low temperature of the mixture at the end of the compression stroke, difficulties can also arise that prevent the fuel from igniting.

But not only these reasons affect the difficult start of a diesel engine. Violation of the adjustment of the advance angle of the beginning of the fuel supply and the development of plunger pairs of the high-pressure fuel pump are quite suitable reasons. The volume of fuel supplied to the cylinders and the normal operation of the injectors depend on the technical condition of the plunger pairs of the fuel pump. The technical condition of the plunger pairs is checked with the KI-16301A device (Fig. 2.1.56).

How to use the KI-16301A? It is connected to the unions of the pumping sections of the fuel pump, but first you need to disconnect the high pressure fuel lines. With a serviceable plunger pair, the developed pressure should be at least 30 MPa (when the engine crankshaft is cranked by the starting device). The seals of the discharge valve are measured by the time the pressure drops from 15 to 10 MPa. The time interval for descent is not less than 10 s. At low values ​​of the pressure gauge of the device, the fuel pump is dismantled (see Fig. 2.1.57, 2.1.58) and changed.

Rice. 2.1.56. How to check the technical condition of the plunger pairs and discharge valves of the MTZ-80, MTZ-82 fuel pump:
1 - device KI-16301 A;
2 - fuel pump

Rice. 2.1.57.How to remove the fuel pump MTZ-80, MTZ-82:
1 - fuel pump;
2 - compressor;
3, 5 - fuel lines;
4 - pump control rod

Rice. 2.1.58. How to unscrew the fuel pump mounting bolts (front view) MTZ-80, MTZ-82:
1 - fuel pump drive gear cover

And once again about gray and black smoke from the exhaust pipe: when the engine is running without load (gray smoke) and the appearance of black smoke with an increase in load occurs when fuel is supplied to the cylinders late.

Engine operation, in which sharp knocks are heard and black smoke is pouring out of the exhaust pipe with increasing load, already indicates an early supply of fuel to the cylinders.

The moment when the fuel supply in sections begins and gives an idea of ​​the angle of the beginning of fuel injection into the cylinders is one of the valuable parameters that clearly affect both the power and economic indicators, and the starting properties of the diesel engine.

After installing a repaired fuel pump or a new one, it becomes necessary to adjust the angle of the start of fuel injection. How to do it? To this end, unscrew the adjusting bolt-stud from the hole in the rear sheet of the engine and push it all the way into the flywheel with the uncut part into the same hole (see Fig. 2.1.59). Turn the crankshaft by the fan drive pulley mounting bolt (Fig. 2.1.60) until the installation bolt-stud aligns with the hole in the flywheel. The valves of the first cylinder are closed at this moment. Such an arrangement of the crankshaft makes it clear that the advance angle of the start of fuel supply is 26 ° to top dead center.

Momentoscope KI-4941 (Fig. 2.1.61) is placed on the union of the first section of the fuel pump. Then open the cover of the gear wheel of the fuel pump drive, unbend the tendrils of the lock plate and unscrew the bolts securing the drive flange (the camshaft of the pump to the gear (see Fig. 2.1.62).

The next stage is pumping the power system. We take the hand pump and pump until the fuel flows without air bubbles from the filter drain tube. We put the fuel supply lever in the position of maximum supply and turn the shaft of the fuel pump clockwise several times until the momentoscope tube is completely filled with fuel (see Fig. 2.1.63).

Rice. 2.1.59. Installation of the stud bolt of the MTZ-80, MTZ-82 tractor
Rice. 2.1.60. How to crank the engine crankshaft MTZ-80, MTZ-82
1 - rear engine sheet; 2 - bolt-stud

Rice. 2.1.61. Installing the momentoscope:
1 - fuel pump;
2 - momentoscope

Rice. 2.1.62. How to unscrew the bolts securing the camshaft drive flange of the MTZ-80, MTZ-82 pump:
1 - splined flange;
2 - lock plate

Rice. 2.1.63. How to turn the shaft of the fuel pump MTZ-80, MTZ-82

Rice. 2.1.64. How to adjust the axial clearance of the MTZ-80, MTZ-82 fuel pump drive gear:
1 - adjusting bolt;
2 - lock nut

Gently shake the tube to remove some of the fuel from it and smoothly turn the pump shaft clockwise until the level of the fuel (meniscus) in the transparent tube of the momentoscope begins to rise.

Holding the pump shaft bolt with a wrench against accidental rotation, look for holes on the splined flange that coincide with the holes of the gear, screw in the fastening bolts and then fasten them with a locking plate.

After the pump drive gear cover is installed, adjust the axial clearance of the fuel pump drive gear with bolt 1 (see Fig. 2.1.64). Having loosened the lock nut, screw in the adjusting bolt to the end, and then unscrew it by half a turn and counter with the nut.

Fuel pump device TNVD MTZ – 80,82

The four-plunger fuel pump (fuel pump) of the d 240 engine is installed in one unit with a booster pump and a centrifugal regulator on the left side of the engine (in the direction of travel of the tractor) and is bolted to the distribution cover. The fuel pump is driven by the crankshaft via timing gears (plunger stroke 8 mm, plunger diameter 8.5 mm).

The injection pump consists of the following main components: plunger pairs, bodies, discharge valve, pushers, camshaft, plunger drive mechanism. The fuel pump head and body are one piece and made of aluminum alloy.

A cast iron plate is attached to the front of the housing to mount the pump to the motor, while the rear has a flange for mounting the regulator. All four pump sections are a miniature fuel pump, whose principle of operation is as follows. During the rotation of the camshaft, the cam protrusion runs into the roller for a certain period of time and raises the pusher. After the cam protrusion comes out from under the roller, the springs lower the pusher. Simultaneously with the pusher, the plunger rises and falls, producing, in this way, a reciprocating movement in the cavity of the sleeve. When the plunger moves down, the fuel fills the space it freed up in the liner. During the upward movement, the plunger compresses the fuel and from the created pressure the discharge valve opens, providing a path for the fuel to the injector. Then the suction and discharge cycle is repeated.

The plunger turning mechanism, which serves to change the fuel supply, consists of a rack and gear rims. On the plunger sleeves there are swivel sleeves equipped with toothed rims. With its projections, the plunger fits into two longitudinal grooves of the swivel sleeve. A plunger spring is put on the sleeve. Through the lower plate, it abuts against the pusher bolt, and through the upper plate - against the pump housing. The toothed rims of the sleeve are in constant engagement with the teeth of the rack, which moves in two bronze bushings. With the help of a thrust, the rack is connected to the regulator levers and moves under their influence, while turning the ring gear simultaneously with the plunger sleeve and thus changing the fuel supply.

On the camshaft, tangential cams are arranged symmetrically to each other. Between the second and third cam there is an eccentric that drives the fuel supply pump.

A bypass valve is located at the top of the rear part of the fuel pump housing of the MTZ 82 tractor, through which the excess fuel supplied by the fuel pump returns to its suction chamber. Thus, the pressure in the channels of the injection pump head of the d-240 diesel is maintained in the range of 0.07-0.12 MPa (0.7-1.2 kgf / cm²). The pushers slide into the holes in the horizontal bulkhead of the fuel pump block. There is a hatch on the side wall of the body, by means of which it regulates the uniformity of the fuel supply through the sections and, in fact, the fuel supply itself. A threaded hole is used to check the oil level in the pump housing.

To communicate the internal cavity of the fuel pump housing with the atmosphere, a breather is used, equipped with an air filter made of elastic foam.

Plunger pair

The plunger pair consists of a sleeve and a plunger, which are the main working elements of the fuel pump. Thanks to it, the required amount of fuel is supplied to the engine cylinders under high pressure. The plunger and bushing are made of alloy steel, after which they are heat treated to form a precision pair. This design is realized because during operation a high pressure is formed in the pump, as a result of which tightness and vapor density are required, blocking the flow of fuel from the space above the plunger. The plunger pair cannot be dismantled and if one of the parts fails, the entire pair is completely replaced.

The upper part of the bushing of the plunger pair has a significant thickening, since in this place it is subjected to severe pressure. The upper thickened part of the sleeve has a step-like end to fit into the socket of the pump housing. In the upper part of the sleeve there are two windows: bypass and suction. Fuel cut-off and bypass pass through the bypass window, and through the suction fuel it is supplied to the over-plunger space. These holes are connected in the upper part of the injection pump with longitudinal channels.The bushing is secured from turning with a pin that goes into the milled groove of the bushing. Falling out of the pins is blocking the hatch cover. The sleeve is located in the pump casing from above, and the discharge valve is pressed against its upper end. To ensure the required tightness, the contacting ends of the discharge valve seat and sleeve have a well-ground surface.

Plunger pair diagram: 1 - fitting; 2 - stop of the pressure valve spring; 3 - the spring of the discharge valve; 4 - a saddle of the discharge valve; 5 - discharge valve; 6 - seal; 7 - bushing; 8 - plunger; 9 - rail; 10 - a gear wreath; 11 - rotary sleeve; 12 - the upper plate of the plunger spring; 13 - plunger spring; 14 - the lower plate of the plunger spring; 15 - clamping screw; 16 and 17 - suction and bypass ports.

The plunger looks like a cylindrical rod, on the surface of which there is a pair of symmetrically placed spiral grooves, one of which is carefully processed and is designed to change the volume of fuel injected into the cylinder of the D-240 engine. During the coincidence of the edge of the bypass window of the sleeve with the edge of the groove, the pressure in the above-plunger space decreases sharply, and therefore the supply of fuel to the nozzle is interrupted. Another groove equalizes the specific pressure of the fuel acting on the side surface of the plunger when the pump is running. On the plunger, below the cut-off edge, there is an annular groove where the leaked fuel is retained, which is then used to lubricate the plunger pair. In the lower part of the plunger, there are two protrusions for controlling its rotation and a head on which the spring plate rests.

Discharge valve

The discharge valve is used to separate the supra-plunger space from the high-pressure fuel line and sharply reduce the pressure in the fuel line when the plunger stops supplying fuel. The valve and seat are made of alloy steel. To create the necessary tightness, the seat and valve are carefully machined and matched to each other. Dismantling of discharge valves is not permissible.

The valve moves in the seat with a cruciform shank, between the supporting belts of which fuel is passed. A spring mounted above the valve tends to press it against the seat. In the upper part of the valve there is a guide collar on which a spring is mounted, and with the second end it abuts against the end of the bore of the pressure fitting. A cylindrical groove called a relief collar is provided between the seat cone and the valve shank.

Discharge valve: a - start of fuel cut-off; b - the valve is closed; 1 - discharge valve; 2 - a saddle of the discharge valve; 3 - unloading belt.

When the plunger stops supplying fuel, the spring under the valve moves it down. At the same time, the unloading belt first separates the high-pressure fuel line from the plunger area, and then, continuing to move along the valve seat opening, acting as a piston, it pumps out part of the fuel from the fuel line, thereby sharply lowering the pressure. Due to this action, an abrupt cessation of the fuel supply occurs.

Maintenance and adjustment of the injection pump of the D-240 engine

Maintenance of the fuel pump consists in checking the oil level (every 120 hours of operation) and its timely replacement in the pump housing (every 480 hours). For more reliable operation of the injection pump on the latest modifications of the D-240 and D-240L engines, circulating pump lubrication from the engine lubrication system is used. Every 960 hours of engine operation, it is recommended to check the compliance of the fuel pump with the set parameters. If necessary, adjust the injection pump.

Checking (adjusting) the fuel pump

Before carrying out the check, it is necessary to make sure that the closing cone of the discharge valve is tight and that there is sufficient pressure in the pump section located in the upper cavity. Rotating the crankshaft, you need to move the regulator until the arrow on the pressure gauge stops at 15 MPa. The engine is then stopped and the fuel supply is turned off with the control lever. When the pressure on the pressure gauge drops in less than 10 seconds, the valve corresponds to serviceability and further use.

To adjust the exact angle of the beginning of the flow of fuel, you will need to twist / unscrew a special adjusting bolt. When unscrewing the bolt, the angle will increase, and when screwing back, it will decrease accordingly. Note that one turn (revolution) of twisting / unwinding adjusts the engine speed by approximately 30-50 rpm. When the bolt is unscrewed, the performance and throughput of the pump proportionally decreases, and when the bolt is tightened, on the contrary, it increases.

Theoretical recommendations

You can logically calculate that with an increase in the fuel supply to the motor, its torque also increases, which, of course, increases the rated power of the D-240 engine. In addition, the high-speed operating mode rises to the limits of its capabilities.

Changing the oil in the UTN pump is necessary only after disassembly and repair, and is not needed in the daily operation of the tractor. Filling of diesel oil should be done through the injection pump crankcase in a volume of 150-200 ml.

if you have any questions about the operation or arrangement of pumps or nozzles, I will try to help

Tell me how to change the bearing on the regulator.

.Dismantle and assemble as I can. there was simply no donor for analysis (I mean the injection pump).
TNVD UTN-5P. Bearings 8110 and 8202.

what type of pump and what bearing exactly?

without a sledgehammer and a chisel, you are not a locksmith, but. at least director
Glory to Ukraine! (And the power will be transferred!)

what was the pumping malfunction? if it gave the solar oil to the pump, then the bearing deteriorated, then not one, but everything, but you will not change everything without a specialist, but if you want to change only the persistent bearings of the regulator, then it’s simple:
1.remove the pump
2. remove the cover of the regulator
3.Unscrew the rail pin and pull it out so that the rail pulls out, if it does not come out, you will have to pull the spring finger and pull the rail pull finger to the other side
4.remove adjuster 6 bolts
7. on a nickle, change the hem. 8202
8. remove the corkscrew ring on the weights and remove them carefully, the rubber dampers will fall out
9. Change bolster 8110 On both bolsters. clips with a smaller inner diameter are packed onto the assembly and then a separator and another clip are placed
10.Adjusting the elastic bands through the special holes in the cargo, we put the cargo in place and so on in the reverse order
AND THE MOST IMPORTANT THING, I EXTREMELY DO NOT RECOMMEND YOU TO DO THIS, AS THE ADJUSTMENTS WILL FLY OUT AND MOST WILL NOT HELP YOU
Well, if not then good luck!

without a sledgehammer and a chisel, you are not a locksmith, but. at least director
Glory to Ukraine! (And the power will be transferred!)

what was the pumping malfunction? if it gave the solar oil to the pump, then the bearing deteriorated, then not one, but everything, but you will not change everything without a specialist, but if you want to change only the persistent bearings of the regulator, then it’s simple:
1.remove the pump
2. remove the cover of the regulator
3.Unscrew the rail pin and pull it out so that the rail pulls out, if it does not come out, you will have to pull the spring finger and pull the rail pull finger to the other side
4.remove adjuster 6 bolts
7. on a nickle, change the hem. 8202
8. remove the corkscrew ring on the weights and remove them carefully, the rubber dampers will fall out
9.Change bolster 5110 On both bolsters. clips with a smaller inner diameter are packed onto the assembly and then a separator and another clip are placed
10.Adjusting the elastic bands through the special holes in the cargo, we put the cargo in place and so on in the reverse order
AND THE MOST IMPORTANT THING, I EXTREMELY DO NOT RECOMMEND YOU TO DO THIS, AS THE ADJUSTMENTS WILL FLY OUT AND MOST WILL NOT HELP YOU
Well, if not then good luck!

Thanks to

,exactly what is needed.

This video is about repair of fuel equipment on diesel engines... The story is about a specialized car service that deals exclusively with diesel engines. It is almost impossible to repair a high-pressure fuel pump with your own hands, so people turn to specialists.

The director of the service gives interviews, where he talks about the work of the company, about which equipment most often gets to them. We also talk about equipment and special tools that are used in the repair of both old-style and new diesel engines, in particular engines equipped with a Common Rail system.

The video also demonstrates diagnostic equipment, with the help of which the auto mechanics of this center identify problems in the fuel network of a diesel engine. This equipment is a special test bench with which it is possible to carry out a complete check of the operation of the fuel systems.
The principle of checking after the repair of the injection pump on such a stand is as follows: the pump is installed on the stand, the required rpm values ​​are set, and the amount of diesel fuel that the pump delivers to different cylinders is recorded.

In addition, employees of the center show a stand where diesel engine injectors are tested. They first go through the bulkhead and replacement of the necessary parts. When installing the nozzle on the stand, its pressure and the correctness of the spray are checked.

High pressure fuel pump in the diesel power system. Violations in the operation of the device, their external manifestations. How can you repair the pump on your own, the sequence of actions. Tips for using specialized services.

Any diesel engine may sooner or later require repair of the high pressure fuel pump. As the human heart begins to "junk" over the years, so this apparatus is subject to age-related changes. Along with the natural wear and tear of parts, refueling with low-quality fuel also affects. Diesel units are more sensitive in this regard than gasoline engines.

The proposed article will help the owners of diesel cars in case of problems with the fuel pump. It also provides tips on how to repair this unit yourself.

The high-pressure fuel pump (TNVD) is an independent unit of the power supply system for internal combustion engines (ICE), primarily diesel. Although this device is also used on gasoline engines with injection injection, it was first used on a diesel engine.

Its main function is to create a pressure difference between the pressure line and the compression chamber in order to ensure reliable injection of fuel into the cylinder cavity. But this is not enough.

The pump also sets the sequence for supplying fuel to the working injectors, that is, it performs a distribution function. In addition, it regulates the flow rate depending on the driving mode (crankshaft speed) and on some other factors: engine temperature, turning the air conditioner on and off.

Finally, just as the ignition timing is adjusted in carburetor engines, the injection pump on a diesel engine automatically adjusts the injection timing.

There are three main types of pumps: in-line, multipoint injection and mainline. Their device is considered in a separate article. It is worth mentioning here only that in-line pumps were used until recently on diesel trucks, tractors and specialized road transport equipment.

Switchgears are installed on all light diesel cars and some trucks.Trunk lines are used in modern Common Rail fuel systems. Such pumps are deprived of the function of fuel distribution; this task is performed by the electronic engine control unit (ECU), which, according to the program, commands the working injectors.

What are the signs of a malfunction of the fuel pump? As mentioned at the beginning of the article, the main reasons for the loss of performance of the high pressure fuel pump are wear of rubbing surfaces and low quality of fuel. Here you can clarify that the low quality of diesel fuel should also mean the ingress of water into the fuel. The following are the external symptoms of a malfunctioning fuel pump:

• It is difficult to start the engine - most likely, the plunger pair (or steam) is worn out, and the pump does not develop the required pressure. It is checked in a simple way. You need to put a rag on the injection pump, pour cold water over it and wait a few minutes. Then try again. If the engine starts, then the reason is really wear. During cooling, the gaps in the interface decrease and the viscosity of the fuel increases, as a result of which the pump provides the required pressure.
• Loss of power. Due to the increased clearances, the injection pressure decreases, and the operation of the all-mode speed controller deteriorates.
• Overheating of the engine. The reasons may be incorrect operation of the automatic injection advance. In this case, it is impossible to postpone the repair of the injection pump "for later".
• The growing "appetite" of the power unit. Caused by fuel leaks, worn plunger couplings, incorrect injection timing.
• Hard work of the engine, which may be the result of too early injection moment and uneven supply of diesel fuel to different cylinders. True, the latter is practically impossible on distribution injection pumps, so, most likely, the matter is in the nozzles.
• Black exhaust from the exhaust pipe. The reason may be too late a fuel injection angle.

If you have any of the above symptoms, consider repairing your fuel pump. Below is considered how to fix some malfunctions of the axial injection pump of the distribution type with your own hands.

It should be noted that before taking on this work, you should study the device of the unit being repaired, find out what tools you may need, because in some cases you cannot do without special equipment, a puller, for example.

You should also prepare a camera to record each stage of disassembly. Otherwise, you can forget where these or those parts were. For disassembly, you need to prepare a suitable table and cover it with a clean cloth or at least a sheet of white paper. There should be no debris on the floor, otherwise an accidentally dropped part may not be found.

So, what can a non-qualified motorist do on his own?

1. eliminate fuel leakage from the pump housing;
2. check the serviceability of the solenoid valve;
3. check the plunger fuel supply mechanism;
4. check the automatic speed controller;
5. clean filter nets;
6. check the pressure developed by the device;
7. adjust the automatic injection advance.

The sequence of actions for self-repair of a high-pressure fuel pump is described below. With the engine running, disconnect the rod connecting the gas pedal with the lever that regulates the fuel supply. Then manually swing the lever in the radial direction, trying to stretch the return spring.

If no diesel oil seeps through the annular gap, then the seal is not worn out. Otherwise, refurbishment of the pairing is required.

While the pump has not yet been removed from the engine, make sure that the fuel shut-off solenoid valve is in good working order. If the engine starts and stops when the key is turned, the valve is working properly.How to deal with a situation when this component fails during movement will be described below.

Now it remains to proceed to disassembling the pump. Before disconnecting the fuel lines and electrical supply from the unit, wipe its body and connections with a cloth soaked in diesel fuel, and then wipe it dry to prevent dirt from entering the fuel system. Rinse the removed pump again, then remove the cover and drain the fuel from it.

First of all, you need to disassemble the drive for adjusting the fuel supply and revise the seals, as well as assess the degree of wear of the mating parts. O-rings must be changed. For this purpose it is necessary to buy a repair kit for the device being repaired.

As for worn parts, there are two ways to restore them: restore the worn axle using chrome plating, or grind and put a repair bronze bushing in the body. The body will have to be bored before this.

Next, you should proceed to disassembling and revising the plunger supercharger. Disconnect the pump distributor head from the housing, and then put it with a pulley downward so that the insides do not spill out. Before removing the cams, the drive gear and the centrifugal regulator clutch, you need to check if these parts are jammed during movement, and then, gently supporting them with your fingers, remove them from the housing.

It is advisable to mark the rollers, washers, axles of the cam clutch with a marker, because all the mating surfaces have already rubbed into each other, and it will be better if they remain after assembly. After disassembly, you need to carefully inspect the parts for chipping or depletion. Replace badly worn elements with new ones.

The wear rate of the plunger pair can only be estimated approximately. The performance of the precision mate is verified after the pump is assembled by measuring its operating pressure. Finally, you need to blow through all filter elements (screens) with compressed air, after which you can assemble the pump in reverse order.

When the unit is assembled, you need to fill it with diesel fuel by turning the drive roller by hand, after which you can put in place and connect the fuel lines, hoses and wiring of the control system.

After the engine is started, you should make sure that the fuel injection advance automat is working correctly, depending on the pressure in the cavity of the low-pressure vane pump. This block has its own idle speed regulator. If necessary, adjust this parameter by tightening or unscrewing the adjusting screw.

Before performing this procedure, it is recommended to memorize the position of the screw by counting the number of threads protruding from the locknut in order to, in extreme cases, return to the original setting. The engine manual indicates the required number of revolutions at idle of the engine. Usually, they decrease from 1100 rpm after starting to 750 - after warming up a diesel engine with a manual transmission, and to 850 - on an engine with an automatic transmission.

In conclusion, the pressure in the pressure line is checked, which is an indirect check of the condition of the plunger pair. For this purpose, you need a pressure gauge designed for pressures up to 350 bar, a connecting hose for connection to the pump and an adapter that includes a bleed valve.

As a measuring device, a TAD-01A manometer or an older one - KI-4802 is suitable. If the adapter is not available on sale, you will have to make it yourself.

Of course, it is necessary to take into account the dimensions of the connecting thread, and where it is planned to screw the connecting hose. For measurement, the device is connected to the central opening of the distribution block or to one of the pressure connections.

After connecting the pressure gauge to the high-pressure fuel pump, turn the pump shaft with a starter and record the dial gauge.If the device shows more than 250 atmospheres, this is normal (with the engine running, the pressure will be higher).

As promised above, a few words about what to do if the fuel shut-off solenoid valve fails along the way. In this case, the engine will suddenly stop. True, there may be several reasons for this. To reject the version of the malfunction of the solenoid valve, it must be excluded from operation, since in normal mode it is always open.

To do this, you need to remove the supply wire, isolate it from the ground, then unscrew the valve, remove the tip with the spring from it and put the device back. If the engine still does not start, the reason is obviously something else. If the engine starts, you need to look for a malfunction in the valve.

To do this off the road, you must first get home. True, you will have to turn off the engine roughly, but simply: put the car on the handbrake, turn on an overdrive and release the clutch pedal.

And then start the repair. First, you should check if the solenoid winding is burnt out. To do this, connect the valve to the battery plus using a piece of good wire, and then try to start the engine. If it starts, then the winding has burned out. Otherwise, look for the place of voltage leakage from the lead wire.

Those who do not have the desire or ability to repair the injection pump on their own should contact a specialized fuel equipment repair station. Although there are dealerships that service and repair cars of a certain brand, they, as a rule, do not deal with fuel equipment, since this requires expensive diagnostic equipment.

The main stand for diagnostics and adjustment of the high pressure fuel pump is Bosch EPS-815. It checks various parameters set for a given pump by the manufacturer. For example: starting fuel supply, volumetric supply in various modes, outlet pressure and some others.

When choosing a service, you should consider its reliability. To do this, you must first arrive for an interview, where you can ask the opinion of the clients served. In such cases, pay attention to the history of the selected service. As a rule, unscrupulous firms exist in the service sector for no more than one year.

The weak link of the injection pump of diesel engines is their sensitivity to water entering the fuel system. Passenger cars, for which water is the main enemy, are especially susceptible to this. To mitigate this danger in winter, keep the fuel level in the tank as high as possible in order to minimize the formation of condensation.