Significantly different from gasoline. But the problems with them are almost the same as with gasoline units. Having read automotive forums, you can see a lot of all sorts of topics where certain problems are discussed. But especially often you can see topics where motorists complain that diesel engines periodically emit black smoke from the exhaust. Let's see what the problem is, why this phenomenon occurs. Let's also see how this problem can be solved.
We make a diagnosis by the colors of the exhaust
Diesel engines, like gasoline engines, can have exhausts of various colors. More often it is white, gray, gray and black smoke.
Let's start with white. Often referred to as white smoke with a bluish tint. This happens when the turbine collapses, and the lubricant gets straight into the intake tract. In such a situation, bluish-colored smoke comes out of the chimney. But an inexperienced motorist will completely take him for white smoke. And if you also smell it, then it is immediately clear and understandable what is the reason for its appearance.
Many in the kitchen at least once, but burned vegetable or butter in a pan. The smell is about the same. Such smoke can also be confused with steam, which is more often observed in the winter months from the exhaust of not only diesel cars. It's all because of the water that appears as a result of combustion.
Later, after the engine warms up, steam will not be noticeable, although this can be easily checked. You just need to put your palms on the exhaust. The palm will be slightly damp. This steam causes significant inconvenience when tuning the engine, and especially in winter. For high-quality tuning, it takes a long time to heat the unit. And in cold weather, the adjustment may not work at all.
White smoke is a signal of a serious problem
If the smoke from your diesel is not steam, then it is definitely coolant that enters the combustion chambers. Usually a cylinder that has been flooded with coolant mixtures does not have the ability to idle. Therefore, the motor can troit.
How does coolant get into the cylinders?
Coolant enters the cylinders due to the poor condition of the intake manifold gaskets. Also, the cause may be a burnt cylinder head gasket, and for diesel engines, most often it may be a cracked block head. In the cylinder head crack, the tank, often full of liquid, also completely goes into the pipe.
Repair
If you find a cylinder head crack, then here you can only recommend replacing the head. However, prices ... Therefore, many motorists do not disdain contract details. These are used parts from Europe.
Cracked cylinder heads can be repaired, but we will not recommend this technology, because during such repairs a hole is drilled that will fall on the crack, and then a copper bar is pressed into the hole. There will be no gas breakthrough here, however, one of the cooling valves will be blocked by half. Such a head will have a significantly reduced resource.
Blue smokes
For those with diesel smoke, the sight of blue smoke made them nervous.
Blue, and on some engines it can be gray, on a working engine it is often caused by late injection. This problem has been said more than once, many motorists have managed to discuss this topic up and down.
Experts say that blue smoke is not scary. In most cases, the problem of late injection is associated with the natural process of wear of the injection pump, of course, if no one touched the pump.
Causes of blue smoke
The fuel pump in our conditions works as follows. A set of parts in this assembly constantly rotates, works, rubs. And lubrication is provided by a pumped diesel. While the diesel is moderately oily, the pump in this mode can work for a very long time. But when the cold comes, winter diesel fuel is poured into the fuel tanks of diesel engines. Everything in it is excellent, but the lubricating fractions are completely absent. Well, almost none. All its fat content, along with various paraffins, was removed at the refinery.
So, when winter comes, most high-pressure fuel pumps on diesel engines run without lubrication and are subject to severe wear. Due to this completely natural, but already too fast and increased wear, the injection advance is reduced. Diesel fuel stops heating up, and the cylinder stops working normally. The engine twitches, shakes. Fuel that does not have time to burn, as a result, turns into blue smoke. Some engines have black smoke coming out of the exhaust. If the engine warms up, then it will stop smoking, or at least the amount of exhaust will decrease. In this case, the fuel has time to warm up and ignite.
If the power unit has low compression characteristics, then the temperature in the combustion chambers is less than necessary. And the fuel will not ignite. If the unit is equipped with a pair of cylinders with good compression, the one with the lower compression will not work.
This picture often happens in parking lots. Cars are trying to start, and the entire area is filled with blue smoke. But sometimes diesel emits black smoke from the exhaust pipe. After warming up, the smoke will disappear. After all, the temperature in the engine is growing, and the temperature increase, even in worn cylinders, will be enough to ignite.
A case from one's life
Mechanics on this subject tell one story. The cylinder head gasket was replaced on the unit. After the motor was assembled, they found a strong shaking at idle. After a couple of kilometers, these vibrations stopped, and after a couple of minutes of work again at idle, the shaking reappeared.
The mechanics analyzed this situation and found out that the new gasket is slightly thicker. Until the diesel engine warmed up to operating temperature, it did not work smoothly.
So, the main cause of blue smoke is late fuel injection and poor compression performance. Many modern engines have a device that injects a little earlier. Cars work harder, but the fuel in the cylinders heats up and burns without smoke, that is, at all. Then the unit heats up, the coolant heats the actuators, and they return the injection advance piston to its rightful place. The motor runs smoother and smoother.
How to remove blue smoke
If the engine shakes and releases diesel black smoke from the exhaust pipe, well, or blue, then you can safely tuck the injection pump. But first you need to see if there is enough fuel. If the pump does not have enough fuel, then the pressure decreases, and this allows the spring to move the timer to late injection. This will cause shaking.
Black smoke
Such smoke can be observed if the fuel does not burn completely. This happens if too much fuel is supplied or the wrong combustible mixture is supplied. If too little air is supplied to the engine, there will be the same effect as if fuel was supplied in excess.
Why is black smoke coming out of a diesel exhaust?
A larger volume of fuel supplied is usually a signal of either improper adjustment of the injection pump, or wear of the injectors, or wear of the speed controller in the pump.
Any fuel pump is equipped with a special adjusting screw. With the help of it, the volume of fuel supplied is adjusted. This screw can only roughly adjust the volume. If this screw is tightened, then the volumes increase. And where there is an increase in volumes, there is also an increase in idle speed. But the turnover can be significantly reduced. Then you can increase the power. But driving diesel black smoke from the exhaust pipe will continue further. If the adjusting screw on the injection pump is screwed even more than it should be, the unit will practically stop reducing speed.
Nozzle wear
Here we can assume that the needle does not fit tightly enough into its seat. And the level of pressure that this needle should raise is reduced. This leads to the fact that excess fuel enters the combustion chambers. It is superfluous, if only because it is supplied not in spray form, but in drops. These drops take a long time to heat up and ignite. Hence the black smoke from the exhaust pipe, and increased fuel consumption (diesel).
the saddest thing
One of the saddest breakdowns that lie in wait for diesel owners is the inevitable wear of the fuel pump. As already mentioned, the giblets inside the pump work without lubrication. If in the summer the diesel still lubricates something, then in the winter it does not. And domestic fuel is generally of poor quality. This is where the internals of the pump wear out.
When the gas pedal is pressed very sharply, for example, in order to quickly move off, the injection pump lever is transferred to increase the volume of fuel supply. This lever will rest on the support. And the position of this very support is already adjusted by the regulator. Therefore, it will not work too sharply to increase the volume. So, pressing the pedal, the driver only wants to give more fuel. And it’s not at all a fact that this will lead to an increase in turnover. It depends directly on how worn out the speed controller is. If it is in good condition, then the car will start with gray smoke. If the wear is large, then the diesel will spit black smoke from the exhaust pipe in a large club.
About lack of air
Also, dark gases from the pipe can sometimes be caused by a lack of air. But in this case, the exhaust will not be black, but rather gray or dark gray. There is also a decrease in power.
This can be caused by a clogged air supply filter. This is by no means a rare case, and this happens to everyone from time to time. Already not 10 or 100 times it has been proven by bitter experience that only 15 minutes will be enough in a traffic jam in front of a KamAZ, which has black smoke from the exhaust pipe. Diesel is on fire, and the new filter of the one in the back can now be thrown into a landfill. But this happens if KamAZ is incorrectly adjusted, although someone has it adjusted.
Also, a lack of air can be observed due to incorrect operation of the EGR and throttle, incorrect clearances in the timing valves. Also, among the reasons may be incorrectly set gas distribution marks, turbine malfunctions.
When a car is turbocharged and you see black smoke coming out of a diesel-turbo exhaust, it's worth checking the boost. Most likely, it is in him. It is also worth looking for cracks in the pipes of the fuel or air system.
One of the car owners poured cleaning for the fuel system into the car. Having traveled a bit, at high speeds when driving uphill, the car puffed black smoke. But after a little puffing, the smoke disappeared and has not reappeared since. At the same time, he checked all the above reasons. He believes that the additive helped. The car didn't smoke anymore. So, it is possible that the cause of smoke in this case may simply be soot from the fuel system, especially if the diesel is equipped with a converter. Sometimes the filter needs to be cleaned from time to time.
Another reason for black smoke from a diesel exhaust pipe
At one of the owners of a diesel car, the engine suddenly began to smoke. At autopsy, nothing intelligible could be found. But after reading various forums, talking with other diesel owners, it turned out that the problem was in the ignition.
After re-opening the control valve was found on the ignition unit. He was advised to hit the adjusting bolt. After that, the car stopped smoking. It turned out that it was the ignition angle.
When the ignition is turned on, a good sensor crackles. What to do if there is black smoke from the exhaust pipe (diesel)? No matter what ignition it appears, the sensor should be removed. If the motor has stopped smoking, and the machine is running smoothly, then it's time to change this element.
Black smoke and cold start
A study of the forums has shown that many complain about the smoke from a diesel engine. Some people say that this is a high pressure fuel pump, but more experienced motorists say that this is not so.
It is believed that this phenomenon is quite normal. It is usually short lived. This can be explained by the fact that during a cold start, a re-enriched mixture is supplied to the cylinders. Hence the black smoke from the exhaust pipe. Diesel "cold" often does this. Therefore, do not panic about this.
The situation with the Kia Sorento
Let's take a concrete example. One of the owners of this car when you press the accelerator pedal thick, black smoke. In motion, the car is very reluctant to gain momentum.
A scan was performed for possible errors in the electronic system, but there are no errors. Analysis of the parameters of work also did not give the desired result. There is simply no defect at first glance. The balance of the nozzles is in a normal state, no serious deviations were noticed, the turbine produces a normal pressure level, but at the same time, the Kia Sorento diesel engine still gave out black smoke from the exhaust pipe. When measuring the readings, they thought about the USR. This is a valve that regulates exhaust gases.
After examining it, they found serious deposits of soot behind the throttle. After removing the exhaust pipe, soot and oil were also found in the intake tract. In the end, everything was removed and cleaned. But a more detailed examination of the valve itself revealed damage to its seat. The valve was eventually replaced.
As a result, there is no smoke, and the car rides noticeably better.
common rail system
Here, too, problems of the same kind are noticeable. Many complain about black smoke from the exhaust pipe - the Comon Rail diesel engine successfully provides such a result during a cold start. Motorists say that this may be due to low-quality fuel or problematic injectors. So, the fuel is not sprayed, but poured. Therefore, black soot. And when the engine warms up, the injectors pump fuel in normal mode.
As a conclusion
We found out the common and popular causes of smoke. Also, when starting "cold", a little black smoke for a diesel is the norm. Most problems can be easily fixed on your own. However, the problem is that all symptoms are suitable for black smoke, and it is not clear what to treat. Therefore, if you have black smoke from the exhaust pipe, diesel troit and twitches, it is better not to tempt fate. In this case, you should give the car for diagnostics to experienced specialists.
So, we found out why black smoke is coming out of the exhaust pipe. Diesel is a complex thing, so these cars need constant care.
Black smoke from the exhaust pipe of a car indicates that the air-fuel mixture is too rich. The operation of the engine on such a mixture increases the wear and tear of parts and assemblies of the cylinder-piston group. This is due to the fact that excess diesel fuel washes oil from the cylinder walls, thereby worsening lubrication. In addition, diesel fuel also enters the oil, diluting it, and worsens lubrication conditions in other engine parts. Often the dilution rate becomes so high that the level of the fuel-oil mixture in the crankcase rises and a characteristic smell appears.
This indicates a malfunction in the power supply, ignition and injection control systems.
Black smoke is a product of incomplete combustion of diesel fuel (soot particles) and is clearly visible against a light background. Accompanied by the following problems:
- high consumption of diesel fuel;
- bad start;
- unstable engine operation;
- high toxicity of exhaust gases;
- power loss.
Causes of black smoke emission from diesel vehicles:
- the air filter is dirty. It needs to be replaced.
- injector malfunction - mainly due to low-quality fuel. Black smoke appears in this case when you sharply press the gas or when driving with a load. A nozzle malfunction is also accompanied by uneven operation of the diesel engine. It starts to shake (very noticeable at low speeds). In such cases, repair is required for a faulty nozzle;
- Injection timing incorrectly set. At an early injection angle, there is a significant delay in self-ignition, an increase in cylinder pressure, which leads to a hard engine, and, in addition, a lot of soot is formed. If the setting of the injection pump angle is correct and the diesel fuel is of high quality, then the injection pump must be repaired together with the injectors;
- turbocharger failure. As a result, the turbocharger does not develop the required boost pressure, or passes a lot of oil into the intake tract due to the fact that the labyrinth seals of the turbine shaft are worn out;
- incorrect conditions for combustion of the air-fuel mixture: low or high compression or lack of air.
At low compression, the engine is difficult to start, power is lost, black smoke appears under load. With increased - the diesel engine is very noisy, detonation knocks are heard. This malfunction is very rare and is associated with errors in the assembly of the motor. The lack of air is associated with a malfunction of the turbine or with a leak in the intake tract. Under load, in this case, black smoke appears and the diesel engine loses power.
High-quality diagnostics will allow you to quickly identify the malfunction and eliminate it. The professional masters of our company carry out diagnostics of diesel engines of trucks using modern methods, thanks to which you can accurately determine the cause of the malfunction.
Operating a car emitting black smoke does not damage the engine or its parts. But a long ride with an early injection angle or with faulty injectors will lead to burnout of the prechambers, destruction of the jumpers and burning of the pistons, which in the future will lead to serious problems for any car.
When accelerating or starting a diesel engine, black smoke comes out of the exhaust pipe. It indicates problems with the engine or fuel system. Let's deal with the source of the black exhaust + video how to fix it.
When examining a smoking engine, first check that the smoke does not stop after the engine reaches operating temperature.
Main reasons
- Clogged air filter or air inlet ()
- Low compression ()
- Faulty boost pressure control system
- Clogged exhaust system
- Valve timing or start of injection incorrectly set
- Glow plug leaking (if equipped)
- Fuel injection pressure too low due to injector firing or wrong type of injector fitted
- Faulty injection pump (high pressure fuel pump) or injection pump of the wrong type
- Motor overload (during acceleration)
Some of the points listed in the description of the causes of malfunctions can be discarded if you carefully examine the very soot from the exhaust (soot particles, drops, oil films, smell).
Black smoke from the exhaust pipe of a diesel engine is produced by incomplete combustion of fuel, when unburned hydrocarbons are converted to soot. Incomplete combustion means that there is either not enough oxygen (i.e. air) in the combustion chamber or too much fuel. An obvious cause of lack of air is a clogged engine filter..
Read about the causes of white and black smoke at.
The cause of poor filling of cylinders with air can also be incorrectly adjusted valve clearances or worn camshaft cams. The fuel may not burn completely if the start of injection is set incorrectly (late injection) or if the injector malfunctions, which does not provide good atomization of the fuel.
Causes of soot may be leaking injectors (opening pressure too low), low fuel cetane number, or excessive coolant entering the combustion chamber.
Video - how to fix it?
To more accurately determine the cause, check the air intake or exhaust system. Also check the boost pressure (on turbocharged diesel engines), valve adjustment, compression in the cylinders, the condition of the cooling system and oil level, and for signs of gas breakthrough into the crankcase.
As I promised in the last article, I will analyze all types of smoke. Today, a series of "black smoke" has come, it can appear both on and on diesel engines. Why this happens and what it means, in detail in this article ...
You know, to my great relief, this does not indicate a serious breakdown of the engine or its auxiliary systems. But if this problem is not eliminated in time, then it is possible to bring the supply system, the fuel ignition system, as well as the engine itself to a deplorable state, because they are the causes of black smoke from the muffler.
Appears: - in the form of a thick black exhaust from the muffler, it goes especially strongly when you press the gas pedal. Moreover, the car does not work stably, often the motor “troits”, it does not start well in the morning (especially in the winter period). Fuel consumption increases.
Main reasons
Black smoke indicates a too saturated (re-enriched) fuel-air mixture. A lot of fuel enters the cylinders, which does not have time to burn efficiently, so the exhaust is repainted black. It is much more toxic and harmful than normal exhaust, because it cannot even contribute to the combustion of excess fuel in the exhaust.
The main reason for this is a malfunction of the fuel supply system, found in all types of internal combustion engines ().
The second reason may be a malfunction in the ignition system, the fuel is not ignited in the chamber and therefore the raw mixture goes directly to the muffler, and the engine will be.
For carburetor ignition
Everything is quite simple with the carburetor - if the exhaust is painted in gray-black tones, there is not stability in the first place you need to look. Most likely, there is an overflow in the float chamber.
This happens for two reasons:
1) The “needle” (needle valve) is faulty, it can stick or, on the contrary, let excess fuel through.
2) Clogged, coked (from our fuel) jets. Small "nozzles" with exact size.
You need to disassemble the carburetor to clean it, if it doesn’t help, then you need to buy a repair kit and replace the “needle” and jets and correctly set the gasoline level in the chamber.
injection option
Everything is a little more complicated on the one hand, and easier on the other. The injector does not have chambers with float needles, etc., it is a completely different system that supplies the fuel-air mixture electronically. Injection into the cylinders occurs with the help of special devices - "injectors", hence the name.
The main causes of black exhaust:
1) Often the cause is the injector itself, it simply clogs and cannot supply fuel normally. There is an accumulation of pressure, and then a “strong” injection, often with excess. The operation of the engine will not be stable, then low revs, then high - in simple words they will “float”. In such a situation, you need to clean the injectors, there are many different ways, from removing the fuel rail to special products that are added to gasoline - it's up to you, but after such manipulation you can often get rid of black smoke from the exhaust pipe. Functionality is restored. Cleaning should be done at least once every 60 - 70,000 kilometers.
2) Since the system is automated, it monitors the various cycles using sensors. So if the sensor is not working, it will either not let the car start at all, or it will supply too much fuel. Here you yourself are unlikely to be able to diagnose a breakdown, you need to go to the service station.
3) Fuel pump. Usually injectors have it in the tank, there have been cases when it applied increased pressure. Which also led to overflow in the injection chambers. Again, it needs to be replaced.
diesel engine
In general, a diesel engine is the record holder for black exhaust. The thing is that it has a slightly different fuel ignition system (from pressure), and it works on diesel (diesel fuel), and even in normal condition it gives a slightly blackish-blue exhaust. Recall at least our "KAMAZ". However, recently they have been struggling with such exhaust, because it is very toxic and poisonous, it contains a lot of lead. Therefore, now almost all diesel engines are equipped with "", for the sake of EURO 5 standards, it cleans the exhaust and prevents harmful substances from entering the air.
Causes of black smoke:
1) This is a commonplace failure of the particulate filter, it just needs to be replaced. However, the intensity of the smoke will not be as high.
2) The high pressure pump is broken. There is an overflow. You just need to change.
3) Incorrect ignition timing. Need to be adjusted.
What can cause such smoke from the exhaust pipe
If measures are not taken in time, then you can run into decent malfunctions. For example, in injection cars, the catalyst dies quickly, but replacing it is not very cheap (many even just remove it).
Also, if there is a large overflow through the "injector", this can almost lead to, because sometimes the fuel is supplied in liquid form, and not in the air mixture. This is very dangerous, complex breakdown.
On a diesel engine from a large volume of fuel, it can break the block, because there is even more pressure there than in gasoline engines.
As you can see, black smoke itself does not cause complex malfunctions, but if you do not react to it in time, this can result in big problems.
When the engines were only carbureted, black exhaust from the muffler meant, in the vast majority of cases, only one thing - worn valve seals. Through which leaked, and burned together with gasoline, in the combustion chamber and oil. However, even then, serious experts, like this, “by eye” determined the difference between such a malfunction (now it is called a gray exhaust), and a situation in which the exhaust was really black.
Causes of black exhaust
When gasoline does not burn, but coke
In fact, the exhaust is painted black by particles of unburned, charred fuel, which simply did not have enough oxygen for detonation, and which turned into coal flakes from exposure to temperature. They then give the exhaust from the muffler a black color. Moreover, this process is usually accompanied by a malfunction of the engine, “triple” at idle, a drop in traction (very noticeable, by the way). Well, this malfunction should be eliminated by adjusting the flow of oxygen into the combustion chamber.
When there is not enough air flow
In fact, everything is very simple. The process of fuel combustion in the engine begins with the fact that gasoline flows from the tank to the carburetor (or to the nozzle, if we are talking about a diesel engine), or to the injector. Here it is sprayed, mixing with the incoming air, turning into a combustible mixture, which detonates in the combustion chamber, alternately pushing the pistons. And if the air flow is not enough, then the black exhaust from the engine is the only possible option. An over-enriched mixture is simply formed, which does not have time to completely burn out. After all, even with a strong fire, remember, first of all they try to block the access of air, oxygen to the source of ignition. And then there will be nothing to burn ...
In this case, you need to adjust the fuel level, clean the carburetor, jets, maybe even everything will cost only by replacing the air filter, which, when clogged, does not let in enough air to create a mixture with the correct ratio of atomized fuel and oxygen.
Abrasive processes in the combustion chamber: what threatens black exhaust
Black exhaust always indicates increased fuel consumption when the engine is running, but this is consumption that does not affect the increase in power. On the contrary, there is a drop in power, and a significant one. And now - the most important thing.
- The fact that black smoke is coming out of the muffler is not the worst thing.
- The fact that this black exhaust is accompanied by a drop in power (at which the car develops 100-120 kilometers per hour in fourth gear) is also not the worst thing.
- Even the fact that gasoline consumption doubles is not the most terrible consequence.
Black exhaust from the muffler threatens serious engine problems due to the fact that coal particles - they do not only fly out of the muffler.
They enter the combustion chamber and, without burning, remaining there, in the space in which the pistons “walk”, stick to the walls of the piston liners, while acting as a kind of abrasive, undermining the walls, which, in theory, should be perfectly smooth and polished . That's what the notorious black exhaust is. It is capable of reducing the life of the engine by an order of magnitude, by several times, causing a complete repair (with grinding or replacement of liners).
Also, unburned excess fuel can enter the lubrication system, diluting the oil, making it unsuitable for lubrication. Sometimes this process is so intense that the oil level in the crankcase increases noticeably. Which, of course, also does not contribute to the long-term operation of the engine. As well as the fact that gasoline that has got on the walls of pistons and cylinders simply washes away the grease. As a result of all this, small scratches can form on the walls, and maybe even serious scuffs, which by no means contribute to the normal operation of the engine.
How to get rid of black exhaust
Carburetor problems...
How to deal with it? How to fix a malfunction in the fuel supply system and establish the process of creating an enriched combustible mixture in which air and atomized fuel would be contained in the proportions necessary for the normal operation of the engine? In fact, you need to look for the true cause of the malfunction. As already mentioned, it may be (if we are talking about a carburetor engine) a clogged air filter that does not let enough air into the system. Black exhaust from the muffler may be the result of a clogged hole in the jet through which air does not enter, or the cause may lie in the excessive supply of gasoline (if the float chamber is incorrectly adjusted and the fuel level in the carburetor goes off scale).
…injection and diesel…
If we are dealing with injection injection, the black exhaust from the muffler may also indicate a malfunction of the fuel consumption sensors (these nodes themselves are designed to regulate the amount of incoming air in accordance with a given rate). Or that the nozzles are leaking, which, by the way, can be very relevant even in the case when black exhaust from the muffler is observed during diesel operation.
Although with a diesel engine, of course, there are certain nuances. On a cold start, black exhaust will be observed in any case. Moreover, a cold start for a diesel engine is a serious test. Not without reason in modern cars equipped with a diesel engine, a preheating system is always provided. But even it does not save from exhaust in the initial stages of operation of a cold-launched engine.
The complexity of the repair: sometimes you can handle it yourself, and sometimes you have to turn to specialists
Here it is important to simply orient yourself correctly and understand whether the exhaust has cleared quickly enough, whether the engine is idling, whether there is a drop in power and increased consumption. If there is at least one of the listed malfunctions, get ready for trouble. Either not quite large (adjustment), or quite serious. Up to replacing the rings of the piston group, or the entire group itself.
To eliminate such a malfunction as black exhaust from a muffler, it may also be necessary to intervene in the operation of the fuel pump or turbocharger (up to replacement), because exhaust can also mean a failure in the fuel supply system. When gasoline comes in too plentifully, and the system for creating a combustible mixture simply cannot cope with such an amount. It may also be necessary to adjust the pressure in the injector nozzles. These are malfunctions that you probably cannot cope with on your own. You will have to contact a specialist.
To save engine life...
Be that as it may, you should clearly know that black exhaust is dangerous not because it spoils the environment (soot flies out of the muffler, it stinks of gasoline), but also disrupts the normal operation of the engine, leads to increased fuel consumption and reduces the efficiency of its work. It should always be remembered that particles of coked fuel not only fly out of the muffler, but also enter the piston group, becoming an abrasive and wearing out the polished (ideally like a mirror) working surface of liners, pistons and sealing rings at an accelerated pace.
This can lead to a noticeable drop in the engine's service life, and instead of the 500,000 kilometers required, say, according to passport data (modern cars are designed for approximately such a resource) before repair, the engine will work an order of magnitude less. That's why black exhaust from the engine muffler is dangerous in the first place.
