Why did the diesel go in razzle: the reasons, the consequences. Diagnostics of diesel engines

The most common engines at the moment are diesel and gasoline. The latter was born much earlier, but now its popularity is falling. Diesel engines are more productive and economical. However, for a motor to meet these two requirements, you need to be able to properly operate it. Do not allow the diesel engine to be spaced apart. Today we will consider what kind of process it is and why it arises.


Sometimes you hear "the diesel went into rags." What does it mean? Spacing is an uncontrolled increase in engine speed, regardless of the position of the accelerator pedal. In most cases, the driver can not control this process. The crankshaft rotates at a high speed, which is constantly increasing. Sometimes the turnover reaches 5 thousand. This is dangerous for a diesel engine. This action takes several minutes. As a result - jammed power unit. Often accompanied by a black thick smoke from the exhaust pipe.

Causes - injection pump

One of the main causes of this phenomenon is the malfunction of a high-pressure fuel pump or slats. As a result, the fuel enters the combustion chamber without restrictions. This is an uncontrolled process. And the more it gets into the camera, the higher the engine speed. After this, the gas distribution mechanism (often with a chain drive) does not have time to react to these changes. As a result of incorrect phase distributions, the crankshaft, intake and exhaust valves are bent. The consequences in most cases are very sad. What if the engine went to races? You can save the unit only in one way - to muffle it. But it is not always possible to make this key. It is necessary to independently cut off access to the combustion chamber. But in some cases, the diameter of the inlet intake is very large. And even with improvised means of closing it will not succeed. The air will still come through small cracks. It is worth noting that in passenger cars, the oxygen intake is at the bottom. Therefore, it is necessary to cut off the feed after the air filter. For this purpose, the screw is loosened by a screwdriver and the supply of oxygen to the nozzle stops. You need to do this as quickly as possible. Remember that here the account goes for a minute. The second option is longer, but more effective. If the engine goes into races, it is necessary to stop the fuel supply by disconnecting the fuel line. But there is not always time for this. The consequences are bending valves and a cranked shaft. What is most terrible - at this time fly fragments of the block of cylinders. The explosion can be compared with the action of a grenade. Is located next to such an engine is just dangerous. But this does not happen immediately, but after 3-5 minutes of the engine running in this mode.


Diesel in raznos can go for various reasons. If it is a turbocharged engine, there is a high probability that this happened precisely because of this mechanism. This element is cooled by oil. Sometimes there are leaks. As a result, the mechanism is not able to provide a boost. The engine speed increases involuntarily. With their increase, the oil pump starts to pump lubrication faster. As a result, it enters the combustion chamber. From the exhaust pipe goes black smoke. With such a malfunction, the unit may even remain without lubrication. After all, all the oil went into the exhaust pipe. There were times when, even after the fuel cutoff, the unit continued to work purely on grease. And let this process last no more than a minute, it is enough to leave the diesel in raznos. Especially often this happens on old military engines. They are designed for the consumption of fuel oil and kerosene. Therefore, it should not be surprising that after the fuel supply stops, the engine continues to operate. If the diesel engine has gone in raznos, the cranked shaft can burst in half. It is not necessary that he tear out the block of cylinders and fly away with the splinters. In some cases, the motor will continue to work, but with characteristic knocking. What else happens when the diesel goes in raznos? With an increase in the number of revolutions, the temperature of the engine increases. He quickly overheats. Also, if it is a leak from a turbine, it is possible to catch fire in the vicinity of the exhaust manifold. Jamming of the pistons occurs in a matter of minutes. And it does not matter what the force of inertia of the flywheel is at the moment. Even if the car is on idle, it is possible to break the connecting rod bolts and other elements of the crank (crank mechanism).

Why only on diesel?

As practice shows, only the diesel engine leaves the car. And for that there are reasons. The speed of the engine on gasoline is regulated by a throttle valve. It passes a certain amount of air, so that the number of shaft rotations can be adjusted from 1 to 7 thousand. On gasoline motorcycle engines, the maximum mark is 10-13 thousand. As for the diesel engine, its operation is controlled by the amount of fuel, rather than air. In the design of such an assembly there is no throttle. And in order to ignite the mixture, it does not need candles and sparks. Even if you remove the battery, this motor will continue to work even further. As for modern diesel engines, they have a much less chance of going into races, since the amount of fuel is strictly metered by the injectors. Here the system is electronically controlled, so if there are problems with the gas pedal, the computer will stop or reduce the partial supply of fuel to the combustion chamber. Usually it takes less than a second. Thus, if the diesel engine went off in a rake, you do not have to unscrew the nipple and the main line yourself, or close the access of oxygen. For you, everything will be done by electronics, and so quickly that you will not notice it.

What to do next?

If you or the electronics were able to drown out the engine that has gone away in anyway, do not re-start it in any case. Try to leave the scene on a tow truck or tow. Re-starting may cause an increased separation of the unit, which you can hardly drown out.

How to avoid a malfunction?

To exclude serious consequences, you need to monitor the performance of the injection pump. The engine, equipped with a turbine or a compressor, should not be spliced with oil or "eat" it in excess of the norm. The limit is 1 liter per ten thousand kilometers. Timely oil change and repair of the cylinder-piston group can reduce the risk of spacing several times. Remember, with a breach of tightness, oil will enter the intake path along with the air. This mixture burns much more intensively. Therefore, the turnover will grow. And so on until the oil is completely over. Also check the ventilation of the crankcase. If it is poorly sealed, the oil vapors enter the intake manifold. When the car's mileage is large, the piston rings are not able to take off the entire film. As a result, the vapor under pressure from the crankcase penetrates into the combustion chamber. It is impossible to control this process.


Adjustment of the injection pump is an obligatory measure for each diesel unit. This pump is driven via a reducer from the crankshaft. His work depends on the current engine speed. To maintain them, use a centrifugal regulator. What should this mechanism do? Thanks to it, the injection pump is automatically adjusted. The device limits fuel delivery at increased crankshaft speeds.

Additional pump adjustment

If the diagnosis of diesel engines shows that the preparation of the mixture is wrong, most likely the cause is in the injection pump, and the centrifugal regulator with this function can not cope. For this purpose a special adjusting stand is used. Before testing, the pump must be cleaned of dirt and other deposits. The injection timing is then checked against the marks and a low-pressure valve is diagnosed. To do this, you need to unscrew the valve and knock with a hammer (light strokes) on its upper part. Next, the cyclic feed is set. It is regulated by means of a lock nut. It, if necessary, is unscrewed or twisted, and then clamped. Normal revolutions of the diesel engine at idle speed - 770-790 per minute. For additional adjustment, the hydraulic corrector is used, rotating its thrust counterclockwise or clockwise. Timely troubleshooting ensures reliable operation of the power system and the engine as a whole.


So, we found out what the process is. Regular repairs and timely diagnostics of diesel engines can reduce the risk of this malfunction. As you can see, the consequences can be the most dangerous, up to the explosion of the power unit. Therefore, if the motor is not controlled to increase the speed and the traction is lost, immediately stop the air supply to the cylinder. On small cars, this can be done with your own hand - cover the intake hose with the palm of your hand.

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