Diagnostics of the condition of engine components and assemblies today costs a lot of money for the family budget. At the same time, it is possible to determine the condition of the engine and quite easily and accurately assess the severity of existing malfunctions by color and shade. exhaust gases.
Probably, many of you have noticed that the smoke from the exhaust pipes different cars it is white, black or gray. This is an important diagnostic feature that directly indicates various malfunctions in the engine and its systems. In the future, we will talk about them.
Most often, the engine starts to smoke with various malfunctions of the fuel supply system, the ignition system, or even the cooling system, breakage or wear of the gas distribution mechanism and (or) cylinder piston group. Depending on the type and nature of the malfunction, the engine begins to smoke heavily when there is an excess of fuel entering the cylinders or when the conditions for its combustion are violated, as well as when various fuels enter the cylinders. technical liquids(water, oil, antifreeze). Depending on the type of fault, traffic fumes take on their characteristic color.
Different colors of exhaust gases
It often happens that a malfunction of one engine system causes the appearance of another, which, in turn, causes it to smoke. For example, a violation of the circulation of fluid in the cooling system can cause systematic overheating of the engine and, as a result, lead to severe wear. piston rings. As a result, more engine oil begins to flow into the engine cylinders. Burning, it gives a bluish tint to the exhaust gases.
When determining an engine malfunction by the color of the exhaust gases, it is also necessary to compare it with other related malfunctions:
- power drop;
- the appearance of detonation knocks;
- increased consumption oils or antifreeze;
- oil stains in expansion tank;
- whitish-milky color of engine oil, etc.
It must also be remembered that the appearance of smoke can occur as a result of the influence of various environmental factors (air temperature, humidity, etc.)
white smoke
Appearance white smoke from the exhaust system when starting and running the engine in warm-up mode - a normal phenomenon. It's not smoke, it's water vapor. The fact is that moisture often condenses in the exhaust pipe, muffler and resonator. You can often see drops of water flowing from exhaust pipe along with the ferry. As the engine warms up, the moisture evaporates and the smoke disappears.
White smoke Water vapor also appears when low temperatures air. And the colder it is outside, the more steam is released from the exhaust pipe. This vapor may be white or slightly bluish in color and is easily dissipated in the surrounding air. If white smoke appears on a well-heated engine, and the oozing liquid is somewhat denser than water and has a specific smell of antifreeze, this is clear evidence of coolant entering the cylinders through a breakdown in the cylinder head gasket (cylinder head), or through cracks in the head or cylinder block.
The hue of the evaporating liquid largely depends on the composition of the coolant used (water, antifreeze or antifreeze), the weather and the engine operating mode. In some cases, it may resemble bluish oil smoke. But, unlike it, the evaporating liquid quickly dissolves in the surrounding air. Also, the evaporating liquid does not leave greasy marks on the heated exhaust pipe.
To check, bring Blank sheet not very thick paper or a dry, clean paper towel to the exhaust pipe warmed up to operating temperature engine. Traces of moisture will gradually evaporate, and greasy oil marks will be clearly visible on the surface of the paper.
To find out the reason for the ingress of coolant into the engine cylinders, it is necessary to carefully remove the cap from the expansion tank or filler neck radiator with the engine running and check for oil film, odor or exhaust bubbles.
Watch a video on diagnosing engine problems with white smoke from the exhaust pipe:
Very often, with a crack in the cylinder block or a breakdown of the gasket, constant fall coolant level without signs of leakage. To check the breakdown, it is enough to pinch the upper pipe leading to the radiator with your hands and start the engine. If, with a known-good thermostat, pressure is felt after a short time, then there is a breakthrough of exhaust gases into the cooling system.
With a pronounced breakdown cylinder head gaskets the fluid in the expansion tank can boil and be thrown out as if overheated. When the engine is stopped, the fluid level begins to gradually decrease. This means that it enters the cylinders through a loose gasket or a crack in the cylinder head. Further, the liquid enters the engine crankcase, where it mixes with engine oil, forming a liquid emulsion of a cloudy or whitish-milky color. The emulsion leaves a characteristic yellow-gray or whitish coating on the oil filler cap.
The ingress of water, antifreeze or antifreeze into the engine cylinder during its operation can lead to water hammer and, as a result, its failure. If the dimensions of the crack or breakdown are insignificant, then these signs may be absent. To check which of the cylinders is leaking fluid, a next procedure. The car is installed on parking brake, the gear is engaged or the engine is blocked. On idle engine the spark plug is turned out, the cap is removed from the radiator or expansion tank. After that, air is supplied to all cylinders in turn with the valves closed. If, when checking any of the cylinders, bubbles appear in the coolant, it means that there is damage that violates the tightness of the cylinder, and further more accurate diagnosis of the malfunction is possible only after dismantling the cylinder head.
Cylinder head gasket burnout In some cases, cylinder head gasket burnout may be preceded by deformation - bending of the cylinder head as a result of engine overheating, for example, when faulty pump, thermostat or fan forced cooling. The cylinder block and cylinder head should also be checked for cracks visually, as well as for special equipment under pressure. In some cases, coolant enters the cylinders through a damaged or loose gasket. intake manifold. In this case, often the liquid enters the combustion chambers through the intake manifold heating systems. In such cases, there are no traces of exhaust gases in the cooling system, but the liquid leaves without visible signs of a leak, and an emulsion is observed in the engine pan.
Similar signs associated with the appearance of whitish smoke require an accurate identification and elimination of the direct cause, otherwise it can lead to more serious damage and, accordingly, to more expensive repairs. After eliminating these faults, it is useful to check the operation of all elements of the cooling system: thermostat, pump, temperature sensor, fan, etc., since in most cases they occur precisely as a result of engine overheating.
black smoke
Black smoke from the exhaust Black smoky smoke from the exhaust pipe in most cases indicates an over-enriched combustible mixture, or a violation of its combustion in the cylinders. Black smoke could be a direct result faulty system ignition, delivery, mixing or injection of fuel.
Black smoke is soot particles deposited on spark plugs, valve plates, cylinder walls and exhaust systems. In addition, the products of incomplete combustion of fuel form coke, which is accompanied by the appearance of detonation, glow ignition (dieseling), and in some cases causes piston rings to stick and valve leaks. The appearance of black smoke is usually accompanied by a sharp increase in fuel consumption, difficult starting and loss of power. On carbureted engines the appearance of black smoke indicates wear of the dosing needle, a violation of the adjustment of the float in the float chamber, or clogging of the air jets.
Also, the cause of strong smoking may be a disturbed setting of the ignition timing. injection engines usually smoke as a result of re-enrichment of the combustible mixture as a result of the failure of various sensors ( absolute pressure, oxygen (lambda probe), mass flow air, etc.), as well as the failure of nozzles, which may pose a risk of water hammer or fire, because. a large amount of fuel can enter the cylinder from a faulty injector. Diesel engines often smoke with black smoke when the injection pump fails, as well as in violation of the adjustment of the fuel injection advance angle.
One of the most unpleasant consequences when black smoke appears increased wear and even breakage of parts of the crank mechanism due to flushing of oil from the cylinder walls big amount fuel. A large amount of fuel, getting from the combustion chamber into the crankcase, dilutes the oil, significantly worsening its lubricating (lubricating) properties. A sign of this is the appearance of a characteristic smell of fuel in the oil (gasoline or diesel fuel in diesel engines).
Blue-gray smoke
bluish gray smoke One of obvious signs excess engine oil entering the combustion chamber is the appearance of a bluish haze from the exhaust pipe. It does not dissipate in the air for a long time and has a characteristic smell. Often, along with smoke at the end of the exhaust pipe, an "oil ring" is noticeable - an enveloping greasy trace. Blueish smoke can be caused by many reasons:
- breakdown;
- wear or wear oil scraper rings and valve bushings;
- wear of the cylinder-piston group;
- using oil of an inappropriate brand and viscosity recommended for this engine;
- wear or failure due to engine overheating valve stem seals.
The most common defect is wear or sticking of piston rings. Often this is accompanied by a drop in engine power, increased oil and fuel consumption. To determine the degree of wear of the cylinder-piston group, it is necessary to check the degree of compression (compression) in all engine cylinders. To do this, it is necessary to unscrew all the spark plugs from the cylinders by shorting the central high-voltage wire to ground or all high voltage wires. Then install a compression gauge on the spark plug hole and ask an assistant to scroll crankshaft engine with a starter. If the compression in any of the cylinders is below 8 - 11, depending on the make and model of the engine, the cause of smoking has been found.
To check the condition of the oil scraper rings, you need to take a syringe, pour 5-10 ml of engine oil into each of the cylinders with it, then install a compression gauge and turn the engine crankshaft. Compression increased by 4-5 indicates breakage, wear or occurrence of oil scraper rings.
The wear of the parts of the cylinder-piston group may be indicated by traces of oil in the intake tract under the air filter, as well as the fact that the engine is very “breathable”. To check, disconnect the crankcase ventilation hose from intake tract and depress the accelerator pedal several times. The gray smoke coming from the hose is more than eloquent about the upcoming replacement of piston rings or an engine overhaul.
In some cases, lubrication of spark plugs up to their closure with a soot bridge and the appearance of strong detonation knocks indicate wear of valve bushings or valve stem seals. In this case, after replacing them, detonation knocks and blue smoke from the exhaust pipe disappear.
Conclusion
In all cases, when the engine starts to smoke, it is categorically not recommended to operate the car, since the consequences of careless driving with faulty engine can result in unexpected and large costs for overhaul or even a complete engine replacement.
Currently, there are many different devices, the purpose of which is to help in the diagnosis of the engine. Some of them work with the engine control unit, allowing you to use self-diagnosis and control tools. executive mechanisms, i.e. fault scanners. Others transmit information about the operation of ignition systems and various sensors. Most of all, an oscilloscope helps with this, of course. With the help of various vacuum gauges and compression gauges, we can obtain information about mechanical condition, i.e., about the compression and tightness of the over-piston space. We can even assess the condition of the inner surface of the cylinders using an endoscope. However, the only device with which we will be able to evaluate how the process of fuel combustion proceeds is a gas analyzer.
There are a great many different tabular data and indications like: "If CH is greater than X percent, you should look here, here and there." No doubt, this is very useful data, and in many cases it really helps. Yes, and know the specific numbers for specific vehicle, one way or another, it is necessary, in any case, it is useful to know that such and such a car has serviceable engine and ignition and fuel supply systems, the content of CH in the exhaust should not exceed Y percent. It is quite another thing to know what these numbers mean and where they come from.
There is an opinion, and we support it, that it is impossible to conduct a competent diagnosis without knowing how the engine actually works. This is much more important than the ability to work with equipment for repair. After all, no device will ever tell you: "The blue-green wire is cut off three centimeters from the ignition switch." This example is given in order to show that any diagnostic tool, not quite scientifically speaking, only gives a hint about where the malfunction may be hiding. The job of a diagnostician is to correctly use this hint and find the cause. And then eliminate it. Well, yes, it’s not so difficult anymore - fixing the problem is usually much easier than finding it. Why such a long intro? Moreover, this article will consider issues more theoretical than practical.
Leak test
So gas analysis. Before proceeding to the actual story about CO and CH, it is worth recalling that any, even the most advanced gas analyzer, will not display the actual content of gases in the exhaust if the exhaust tract is leaking. That is, it will give incorrect information. It would seem that if the pressure in the exhaust pipe is higher than atmospheric pressure, how can air get there? To answer this question, we must remember that they leave the cylinders not in a continuous flow, but cyclically: between the moments when the exhaust valve opens and the gases exit the cylinder, there are moments when the exhaust valve is closed and the gases move through the pipe, so to speak , by inertia. At these moments, they create a vacuum in the pipe. The result of which is just the suction of atmospheric air.
The result is confusing readings and unnecessary headache diagnostician. Therefore, we repeat, it is always necessary to check the exhaust tract for leaks before carrying out the test. There are two ways to do this. The first one is more innovative. As you know, there are special smoke generators, similar to those used in the performances of singers and artists. The bottom line is that when the dense smoke they create moves along the highway, all leaks immediately become visible. According to Ryazanov, many of those with whom he had to communicate want to use such a device in their work. Despite this, almost no one uses it.
It's hard to say why. Most likely it's the price. Fluid to create smoke is quite expensive. Therefore, the second method is almost universally used, which has a fairly respectable age in order to be called "grandfather". Despite this, he has not lost efficiency and is unlikely to lose it until the exhaust system is made radically different. The meaning is banal to the point of triviality: one person is clamping something on the outlet of the exhaust pipe. Thus, the pressure in it increases. The other person simply runs his hand next to the exhaust pipe, along its entire length. If the hand feels the movement of air, it is very likely that there is a leak in this place. The second method, despite its archaism, certainly wins in the Efficiency / Price ratio.
What is the output
After making sure that the exhaust tract is tight, we connect the gas analyzer. The engine is started, the exhaust gases come out, and the gas analyzer diligently, pardon the tautology, analyzes them, showing various numbers. What is what? Let's start from afar. When gasoline is burned, if you look in a chemistry textbook (and combustion is nothing but a chemical reaction), H20 and CO2 are obtained. Unfortunately, this happens only with complete ideal combustion of the mixture. There are no ideal processes in life. In the engines internal combustion this unfortunate fact is reinforced by the fact that we are dealing with a dynamic process.In the process of combustion, the volume also changes (because the piston moves), and the temperature, and pressure, and even the thermal conductivity of the medium itself. It is very, very difficult to calculate the combustion process of the mixture in the combustion chamber. We owe all this to the content of all kinds of foreign substances in the exhaust. The best known of these are the good old CO and CH. What are they? CH is a general term for all the hydrocarbons that come from unburned gasoline (all of them, not just one in particular, as some auto repairers believe). That is, again, CH is simply unburned gasoline. CO is gasoline that began to burn, but for some reason he was not lucky enough to find another oxygen molecule in order to burn out (that is, oxidize) to CO2. For a better understanding, Ryazanov gives an analogy with a fire:
 |
This is how the composition of the exhaust gases looks good with normal mixture formation. As you can see, the values of the parameters are within the normal range, but not the reference ones. |
 |
Here we see an increased content of CH. The most common cause of this is a misfire. In addition to CH, an increased oxygen content is also noticeable. Oxygen enters the exhaust gases from the combustion chamber along with unburned gasoline |
 |
IN this case there are leaks in the connections. At the same time, atmospheric air is sucked in. As a result, the oxygen content increases significantly, while the amount of other gases remains almost the same, because their content in atmospheric air small. Along with the increased amount of oxygen, the gas analyzer also shows an increased calculated lambda coefficient. |
 |
The composition of the exhaust gases of an engine that meets Euro-2 standards. The effect of the catalyst is immediately felt, which regularly burns the exhaust gases. The CO content is below the measurement limit of the gas analyzer used. CH is also very small. About good combustion of fuel says and high content CO2 coupled with low oxygen content. And the lambda parameter, respectively, is almost equal to 1. |
Once upon a time, when injectors were mostly thought of, but used almost everywhere, and gas analyzers were a match. With what could be obtained from carburetor mixture formation, these two parameters were quite enough for both diagnostics and for adjusting the fuel supply system. Now things have become more difficult. First, environmental regulations have become more stringent.
Secondly, injection systems allow for more accurate mixture formation. But in order to use this exact mixture formation, the two above-mentioned parameters are not enough. Therefore, other gases must also be taken into account at present. Which? First, the CO2 content is now also taken into account. This is a product of the complete combustion of gasoline, and it is also important. In addition, the exhaust contains oxygen and various oxides of nitrogen. Where do nitrogen oxides come from? The answer is logical: they are taken from the air, because it is in the air that contains about 80% of nitrogen. And at temperatures of the order of 1000 ° C, nitrogen quite willingly begins to react with oxygen, i.e., burn.
Since a temperature of 1000 ° C is not something extraordinary for a combustion chamber, the appearance of nitrogen oxides is natural and even expected. From the foregoing, by the way, it is worth concluding that using a two-component gas analyzer is similar to hanging a sign over the entrance: “We are not professionals.” At a minimum, a four-component device is required. Four-component gas analyzers measure the content of CO, CH, NOx, CO2.
Five-component gas analyzers also measure the amount of oxygen. The use of a five-component gas analyzer is still preferable. However, when choosing “there is no gas analyzer at all or there is a two-component one”, of course, it is worth giving preference to the second option.
I would also like to take a break important nuance. If the first four parameters are measured using infrared cameras, then the oxygen sensor (to measure the amount of oxygen) works on a different principle. Therefore, it has a certain service life, and it must be changed periodically. In addition, since the air also contains a decent amount of oxygen, this sensor starts working from the moment it comes into contact with the atmosphere. Two facts follow from this: firstly, regardless of whether you used a gas analyzer or not, this does not affect the frequency of replacing the oxygen sensor; secondly, when buying an oxygen sensor, it is necessary to check the tightness of the package. If it is leaking, then the service life of this sensor will be less by exactly as many days as have passed since the package was leaking. And to establish when this happened is unlikely to succeed.
CH, as already mentioned, is unburned fuel. If given parameter too high, it means that gasoline does not burn completely. This is possible in two cases:
1) rich mixture. Everything is simple here. Lots of petrol. There is little air. And not every molecule of gasoline has an oxygen molecule. The fuel would like to burn, but there is not enough oxygen. So gasoline is literally thrown into the pipe;
2)lean mixture. Yes, it sounds paradoxical. It would seem that there is enough oxygen and not a single molecule of gasoline will leave offended. However, this does not happen, and gasoline does not burn.
How to understand whether we have a poor or rich mixture? This is where the knowledge of the second parameter comes to the rescue. As already mentioned, CO is the gasoline that started to burn, but something prevented it from doing so. And the lack of oxygen prevented him from doing this. In the case of poor mixtures of oxygen, we have an abundance, and if a gasoline molecule stumbles upon an oxygen molecule, then the second oxygen molecule is probably somewhere close. Therefore, if a gasoline molecule starts to burn (i.e., oxidize), it will oxidize for sure. Thus, with lean mixtures, the CO content approaches zero. In the case of a rich mixture of oxygen, no one is enough. Therefore, along with the increased CH, there will also be an increased CO.
Unfortunately, even with an ideal composition of the mixture, perfect combustion will not be achieved and actually fuel will go into the pipe, from which you can still get useful work. It is burned in the catalyst (if any). We do not receive mechanical energy from this, but at least we do not spoil the environment.
As you can see, already knowing only two parameters, you can draw some conclusions about how the engine works.
Gas analysis to the rescue
However, the possibilities of gas analysis are by no means limited to this, but rather, they are just beginning. Take for consideration such a malfunction as misfiring. Misfires are fundamentally divided into two cases: misfiring, when for some reason there is no spark, and a violation of the formation of the charge of the mixture, when there is a spark, but the fuel does not burn. One of the reasons for violations of the charge formation of the mixture is wrong job nozzles. That is, the nozzle does not spray fuel with an even flame, but simply delivers gasoline in a large drop.
As you know, gasoline itself does not burn, but its vapors burn in a mixture with air. Therefore, if we have a drop of pure gasoline surrounded by pure air, it will not ignite. One way or another, if we are faced with a misfire problem, options are possible. The simplest case is when the engine troit, that is, one cylinder simply does not work. It is quite simple to decide here: check the spark, check whether fuel is supplied. All in all, standard set procedures.
It is much worse when skips occur randomly. Now the first cylinder did not work, then the second, etc. That is, there is no one clearly idle cylinder, which can be clearly identified. With such a problem, an unpleasant effect appears: vibrations of the engine and the car as a whole.
It should be noted that the cause of vibrations can be not only misfires. For example, the reason for this may simply be a broken belt that drives balance shaft, or just broken pillows engine mounts.
This is where the gas analyzer is practically indispensable, because it saves a lot of time and labor on testing the hypothesis. If everything is normal with ignition, then the composition of the exhaust will be normal. If misfires are present, this will clearly appear on the readings.
First, if the fuel does not burn, it simply goes into the exhaust. It's already sharp rise CH. In addition, during normal combustion of the mixture, CO2 is also released. The content of CO2 in the air is low; if the mixture does not burn, then the air also goes into the exhaust. Therefore, the CO2 content in the exhaust will be reduced. In addition, the air going into the exhaust dramatically increases the amount of oxygen. This method, of course, will not tell whether the matter is in ignition, or in the formation of the mixture.
But it's wrong to complain. Connecting a motor tester and checking the operation of the ignition system is unlikely to be a problem for a knowledgeable person. And it's much easier to search when you know what you're looking for. Moving from the particular to the general, gas analysis allows us to determine a certain general line of troubleshooting.
An example is a very common customer complaint about high flow fuel. It is worth noting here that first of all it is worth asking the owner about the driving style. True, as the experience of a large number of diagnosticians shows, the vast majority of customers say that they drive calmly. Unfortunately the concept quiet ride everyone has their own. Therefore, after questioning the client, it is necessary to trust impartial instruments. Or rather, first to one impartial device, the benefits of which we are talking about in this article.
The most likely reason big expense is naturally a rich mixture. But at the same time, do not forget that a lean mixture can also cause the same problem. Why this happens - it was said above, but we will repeat. With a lean mixture, it still does not complete combustion fuel. In this case, the engine does not develop the necessary power, and the driver's instinctive action is to press the gas pedal harder. It turns out that the fuel not only does not burn, but the amount of this unburned fuel increases as a result of attempts to step on the gas.
How to reduce the toxicity of exhaust gases on your own and pass MOT
In 80%, the toxicity of exhaust gases is influenced by several main factors:
1. Fuel (the first and main factor)
2. Engine condition (wear, contamination)
3. (type, quality, purity)
4. Condition (resistance)
Let's take a look at each of the factors.
1. Fuel. Before you go to technical inspection, a few days before, should only be poured quality gasoline high octane rating. This approach will dramatically reduce the content of toxins in the exhaust gases.
2. Engine condition. This is the most common factor that leads to a change in the composition of the exhaust. It is recommended to clean the fuel system twice a year and remember to change the fuel filter periodically. The condition of the spark plugs greatly affects toxicity, it is recommended to replace them before maintenance.
3. Engine oil. Oddly enough, the quality of engine oil also changes the composition of exhaust gases. Synthetic engine oil leads to a decrease in toxicity, and mineral to an increase. Therefore, before undergoing maintenance, it is recommended to replace the old engine oil with fresh, it is only necessary to use quality oil purchased from official representatives.
4. Condition air filter. Everyone knows that the resistance of the air filter (pollution) causes a decrease in power, to excessive discharge in the intake manifold and an increase in toxicity. Before passing MOT, it should also be replaced with a new one!
Car owners know that sometimes their favorite vehicle suddenly starts to behave “wrong”. One of the symptoms that can be detected with the naked eye and may disturb the sensitive owner is exhaust pipe smoke. This article, of course, does not claim to be an exhaustive troubleshooting guide, but it can give at least some idea of where to start worrying.
The smoke from the exhaust pipe can be roughly divided into white, blue and black. To get smoke of other colors, you will need not an internal combustion engine, but some other unit.
White smoke is essentially not smoke, but water vapour. During the combustion of fuel in the engine, a certain amount of water vapor is always formed, which partially condenses in an unheated exhaust system and becomes visible. How colder car, the denser the steam is. This is a completely normal phenomenon: who has not seen how cars are wrapped in a whitish cloud in winter?
An alarming symptom is the visible white steam coming from the pipe of the car in warm weather and a well-warmed engine. This may be due to the ingress of coolant into the combustion chambers. Sometimes such steam becomes a bluish hue and resembles "oily" smoke. However, unlike him, the vapor quickly dissipates in the air. You can make sure that this is steam by attaching a sheet of white paper to the pipe: the moisture that has fallen on the paper will gradually dry out, leaving no oily trace.
Coolant can get into the combustion zone of the fuel different ways: through the head gasket, through microcracks in the cylinder block and others. The same way in reverse side exhaust gases enter the cooling system. All this is reflected in the coolant: its level in the expansion tank is lowered, and when the engine is running, gas bubbles can be seen in the tank.
With some malfunctions, for example, if liquid enters the cylinders due to leaks in the intake manifold gasket, no gases are formed in the expansion tank. However, in any case, the coolant enters the oil and gradually turns it into an emulsion, which, of course, does not improve its lubricating properties.
All of the above means that it's time to show the car to repair specialists. The described defects progress rapidly as the car is used, worsening the properties of the oil, which in turn leads to destruction. various nodes engine and eventually lead to engine failure.
The black color of the exhaust is obtained when it contains in large numbers soot particles appear, which in turn is formed due to incomplete combustion of fuel in the engine. Such smoke is especially clearly visible against a light background (try not to have the snow-white board of a neighbor's SUV turn out to be this background).
Incomplete combustion is the result of oversaturation air-fuel mixture. This can be confirmed by such symptoms as increased fuel consumption, unstable engine operation, loss of power.
In different designs of engines, various reasons can lead to this. In carburetor engines, this may be a malfunction of the needle valve or air jets. In engines with electronic injection- Incorrect operation of fuel system control sensors or leakage of injectors. In diesel engines - pump defects high pressure or incorrect fuel injection setting.
A common cause of over-enrichment of the mixture may be a decrease in engine compression. In this case, the mixture does not enter enough air, which means that the specific amount of fuel increases, which leads to the fact that part of it does not burn in the engine cylinders.
Environmental pollution and fuel consumption are not the only consequences of incomplete combustion of fuel. This has a very negative effect on the condition of the engine oil. It is saturated with soot particles, which, spreading through the lubrication channels, actively pollute the engine and oil filters, which leads to disruption of heat exchange. And this, in turn, is fraught with burnout of pistons or valves, and hence a much more serious repair. How faster car with a black smoky tail will head for repair shops, the cheaper the owner will get off.
Finally, blue smoke, in the whole spectrum of shades from gray to pale blue, indicates that not only fuel is burning in the engine cylinders, but also oil penetrating there. The same simple test with a sheet of paper near the exhaust pipe can confirm the guess: this time, oil stains will appear on it.
The causes of oil leakage into the fuel combustion chamber are mainly related to the wear of parts: a change in the shape of the cylinder liner, damage to the piston rings, increased clearances between the valve stems and guide bushings, and so on. It is better to entrust a specialist to understand what exactly needs to be repaired. It is only important to pay attention to the smoke that has appeared in time.
With slight wear, smoke may appear only when starting a cold engine. Upon subsequent heating, the parts expand and the gaps return to normal and the engine runs normally. With high wear, everything happens the other way around, as it warms up, the smoke becomes denser. This is due to the fact that hot oil has a lower viscosity and more easily penetrates through "abnormal" gaps, which can no longer return to normal only due to the expansion of the metal.
In all the cases described above, the car can move for some more time, the duration of which depends on the nature of the malfunction and many other conditions. This period can be extended by treating the engine with means that restore the surface layer of parts under friction conditions, primarily in cylinder-piston group. Agents such as geomodifiers help protect the oil from fuel, coolant, or soot particles. In addition, the resurfaced surface is able to retain a denser oil layer, which to some extent compensates for the reduction in oil performance. And this, in turn, protects other components and mechanisms from damage.
Such remedies are not a panacea and cannot replace the repair of a malfunction that leads to the appearance of smoke from the exhaust pipe, but they can help to avoid more significant troubles.
When surfing the road, do not forget to look back - what color is the train stretching for your miracle bird!
We all strive for reliable and comfortable rides by paying due attention to our car - constantly investing time and money in it. ideal condition. But in any case, the operation of the machine is accompanied by various failures and malfunctions. Here it is already necessary to determine the appropriate diagnostic methods - we will try to pay more attention to automotive exhaust, which can tell a lot about the current state of the car.
Many experienced drivers are well aware that the color of exhaust gases can indicate various malfunctions in the car. With smoke of different colors from the exhaust pipe during engine operation, from white to black, we can confidently say that there are problems in normal operation vehicle.
Mandatory condition in similar situation- timely diagnosis and elimination of the problem, responding to dangerous symptoms. After all, it is better and cheaper to fix the problem at an early stage, in order to then bear the serious costs of dealing with possible consequences.
What the color of exhaust gases can tell about - more about possible problems
In our article, we will take a closer look at what the color of the exhaust gases can tell - by analyzing possible malfunctions in the car that can be diagnosed based on the color of the exhaust gases. We will pay our attention to situations using the examples of carburetor and injection gasoline engines.
However, before considering possible faults car should focus on a number of basic nuances. First of all, it is worth remembering that white smoke when starting the engine in a cold season is considered a completely natural phenomenon if it disappears after the engine has been thoroughly warmed up. Whitish smoke in this case is caused by steam generated during the combustion of condensate in fuel system cars.
Not indicative of any problem also slightly visible smoke white color from the exhaust pipe in the cold season. Although such smoke is clearly visible during a severe frost, it is a completely normal event. Just remember - every person in the winter will also emit white vapor when breathing.
You just need to understand the differences between steam and white smoke. There should not be any particular difficulties here. The vapor is translucent and dissipates fairly quickly after being released from the pipe.
The smoke is quite dense, it will stretch in a plume, it can dissipate quickly only with wind.
However, the possible color of the smoke from the exhaust pipe is not limited to a white tint. The appearance of a bluish, black or gray color is also possible. Color varies depending on quality fuel mixture(usually when re-enriching the fuel), and from mixture impurities in the fuel mixture during engine operation. Such impurities can be coolant or engine oil. Complete combustion of such impurities in the cylinders does not occur - the exhaust is painted in different colors.
The fuel supply mechanism is responsible for the poor-quality preparation of the fuel mixture. The ingress of third-party liquids into the cylinders indicates excessive wear of certain components of the piston group. However, this question cannot be considered unambiguous.
Therefore, smoke indicates significant problems in the functioning of the engine - during the operation of the cooling system or fuel supply. To eliminate the real cause of the appearance of smoke, a diagnosis of the main problems is required - comparing possible facts.
Let's take a look at the most common situations as an example.
What the color of exhaust gases can tell about - problems with an injection engine
Evidence of breakdowns or malfunctions of the injection type is the exhaust of a blue, black or white hue.
Black car exhaust
Black exhaust fumes may be produced and discharged. The cause of this problem is often the inflow of over-enriched fuel. A corresponding problem appears as a result of a breakdown of any sensor or if a control failure of the fuel supply system unit fails. In this situation, the problem is solved by simply replacing the sensors (if the problem is in it) or by replacing the control unit (such a procedure will require a lot of time, money and effort).
Blue or white car exhaust
A common cause of blue or white exhaust is often water in the fuel or the presence of an oil mixture in the combustion chamber.
What can the color of exhaust gases tell about - a carburetor engine
White car exhaust
Cause white exhaust usually is the water content of the fuel. This problem can be caused by many factors - including condensation, high level air humidity during refueling, or malfunctions of the cooling system.
blue car exhaust
Blue or bluish exhaust is caused by oil entering the combustion chamber. The cause of this problem is often the deterioration of the pistons and cylinders of the fuel system.
Often, the presence of breakdowns, deposits or wear of piston rings leads to a blue exhaust.
Black car exhaust
The reason for such exhausts may be insufficient combustion of the fuel mixture, thick soot is formed. Usually the problem is caused by an excessively rich fuel mixture being fed into the carburetor. However, other additional reasons are possible, which it is better to ask your experienced drivers or experts - diagnostics will be made, taking into account additional "symptoms" and the condition of the car.
In our article, we focused only on the main possible problems. In each case, the circumstances and situation are individual, but we hope that the recommendations collected will help to eliminate the problem.
It remains only to wish stable operation car, so that you do not have to deal with expensive diagnostics and troubleshooting. Be attentive to the condition of the car - all the more so, he himself will be able to give the appropriate signals, including by changing the color of the exhaust gases.
For many drivers who have even the most insignificant driving experience, the presence of a non-standard color of smoke coming from the exhaust pipe signals the need for maintenance to identify problems. This kind of malfunction cannot occur without certain reasons, and exhaust color we will already hint where to start looking for a breakdown.
car exhaust
The smoke coming out of the chimney can be very bad smell both color and suspicious density. The colors of exhaust gases during malfunctioning can be:
- White;
- Black;
- gray-haired;
- Blue and blue colors.
- Malfunctions in the gas distribution mechanism or in the IPG (cylinder-piston group);
- Breakdowns in the injection control system;
- Malfunctions in the area of the cooling system.
It should be noted that the state of exhaust gases is significantly affected by the weather. Experts recommend that diagnostics be carried out exclusively in “flying” weather for more exact definition shade of gases.
Fault Compliance
The color of smoke that can most often be found as a result of a malfunction can be white, gray, or black. Specifically, these three colors will be discussed further.
The presence of black smoke should be considered initially, as black discoloration of gases is the most common "phenomenon". It is highly visible in all weather conditions. It often has an unpleasant odor. It occurs due to incomplete combustion of fuel, which subsequently flies out with the exhaust. As a result of this defect, the engine may begin to lose power, fuel consumption increases significantly, and difficulties may also arise with the process of starting the vehicle.
In such a situation, you should first check:
- Carburetor;
- ignition coil;
- Spark plug;
- nozzles;
- motor compression;
- Air filter (it may need to be cleaned);
- Poor fuel quality.
Having examined all the above listed parts of the vehicle, you can easily identify the cause of black smoke and fix the problem.
White exhaust smoke
Sometimes the presence of white smoke does not indicate a malfunction. In some cases, it is enough to simply check the quality of the fuel and see if the coolant needs to be replaced. If the problem does not go away on its own after performing these procedures, then this is a sure sign that there has been a breakdown of the cylinder head gasket - the cylinder head. This kind of problem should be fixed immediately. Otherwise, the motor will overheat.
As regards the availability gray smoke, then there is only one conclusion: the problem is in the motor itself. This shade can give burnt oil entering the combustion chamber. The reasons for such a defect can be:
- Sudden wear of parts inside the engine itself;
- Loss of elasticity of the piston rings.
As you can see, the color of the exhaust gases tells us a lot, but do not be too afraid of the appearance of an unusual color and smell of the exhaust. It is enough to determine the cause of its occurrence in time and eliminate it. But if you start to delay the diagnosis, you can say goodbye to your "swallow", it will not last long.
Incorrect color of exhaust gases - an example of blue smoke
