What Does The Color Of Spark Plugs Mean

Photo No. 1 shows a candle turned out of the engine whose work can be considered excellent. The skirt of the central electrode is light brown, soot and deposits are minimal. The complete absence of traces of oil. The owner of this engine can only be envied, and there is a reason for this economical fuel consumption and the lack of the need to add oil from replacement to replacement.

Photo 2 shows a typical example of a spark plug from an engine with increased fuel consumption. The central electrode is covered with a velvety black deposit. There are several reasons for this: a rich air-fuel mixture (improper carburetor adjustment or injector malfunction), clogged air filter.

In the third photo, on the contrary, an example of an excessively poor air-fuel mixture. The color of the electrode is from light gray to white. There is cause for concern here. Driving on too lean a mixture and at increased loads can cause significant overheating of both the candle itself and the combustion chamber, and overheating of the combustion chamber is a direct way to burnout of exhaust valves. The skirt of the central electrode of the candle shown in the photo

No. 4 has a characteristic reddish tint, this color can be compared with the color of red brick. This redness is caused by the operation of the engine on fuel containing an excessive amount of metal-containing additives. Long-term use of such fuel will lead to the fact that metal deposits form a conductive coating on the insulation surface, through which it will be easier for the current to pass than between the electrodes of the candle, and the candle will stop working.

Photo No. 5. The candle has pronounced traces of oil, especially in the threaded part. An engine with such candles after a long standby, tends to “troit” for some time after starting, and as it warms up, the work stabilizes. The reason for this is the poor condition of the valve stem seals. There is an increased oil consumption. In the first minutes of engine operation, at the time of heating, a characteristic white-blue exhaust.

The candle in photo No. 6 is turned out of the idle cylinder. The central electrode and its skirt are covered with a dense layer of oil mixed with drops of unburned fuel and small particles from the destruction that occurred in this cylinder. The reason for this is the destruction of one of the valves or the breakdown of the partitions between the piston rings with the ingress of metal particles between the valve and its seat. In this case, the engine “troit” is not ceasing, a significant loss of power is noticeable, fuel consumption increases by one and a half, two times. There is only one way out. repair.

Photo No. 7 is the complete destruction of the central electrode with its ceramic skirt. The cause of this destruction could be one of the following factors: prolonged operation of the engine with detonation, the use of fuel with a low octane rating, very early ignition, and just a defective candle. Symptoms of the engine are the same as in the previous case. The only thing you can hope for is that the particles of the central electrode managed to slip into the exhaust system without being stuck under the exhaust valve, otherwise the cylinder head repair also cannot be avoided. But it depends on the person, whether he is sinful or not (a joke). If we talk about this particular candle, then God blessed its owner.

Photo number 8 is the last in this review. The candle electrode is overgrown with ash deposits, the color does not play a decisive role, it only indicates the operation of the fuel system. The cause of this build-up is the burning of oil due to the development or occurrence of oil scraper piston rings. The engine has an increased oil consumption, when overgassing from the exhaust pipe there is a strong, blue smoke, the smell of the exhaust is similar to a motorcycle. If you want less problems for your engine, don’t forget about candles only when the engine refuses to work. The manufacturer guarantees trouble-free operation of the spark plug on a serviceable engine of 30 thousand kilometers. But you, in turn, do not forget to check the condition of the candles with each oil change or on average every 10 thousand kilometers. First of all, it is the adjustment of the gap to the required value, the removal of carbon deposits. It is better to remove carbon deposits with a metal brush, ceramics of the central electrode are destroyed by sandblasting, and you run the risk of getting a copy from photo No. 7. I would also recommend changing the candles in places, this is due to different temperature conditions of the cylinders.

What can you understand by the color of the spark plugs when checking

Spark plugs are an essential part that is necessary for the operation of a gasoline engine. The main task is the formation of a spark in the combustion chamber, due to which it is possible to realize ignition of the fuel-air mixture in the cylinder.

Note that any violations in the process of sparking lead to the fact that the engine begins to lose power, there is an increased fuel consumption, reactions to pressing the gas pedal are slowed down, the power unit starts to work unstably, troits, has a toxic exhaust, etc.

At the same time, for experienced car enthusiasts and professional auto mechanics, color spark plug diagnostics is a reliable way to determine the condition of the entire engine, identify possible problems and failures. The fact is that these elements are located in the combustion chamber and are a kind of indicator of the internal combustion engine state.

Such knowledge can be useful both in the case of checking the candles themselves or in the process of searching for various engine malfunctions, and when buying a used car with an unknown history. Next, we will consider what the correct color of the spark plugs should be, as well as what color of the spark plugs which means and which engine failures indicate in a particular case.

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Different color of spark plugs: as indicated by

As already mentioned, the appearance of the candle allows you to evaluate the quality of work and the general condition of the entire engine, as well as its individual components and mechanisms. We note right away that it is only necessary to start inspecting candles after the engine has warmed up well and reached operating temperatures, and also worked in the loaded mode before the inspection.

  1. So, let’s look at the meaning of the colors of the spark plugs, which can be seen after they are twisted on various internal combustion engines. To begin with, the normal color of the spark plug is such that when the skirt of the central electrode is light brown, there is practically no soot and various deposits. Oiling should also not be visible. This color of the working candles indicates the efficiency of the engine, the completeness of combustion of the mixture in the cylinders, the absence of oil consumption due to wear of the timing or CPG.
  2. If after twisting it is clear that black fluffy soot has accumulated on the central electrode, then this indicates problems with the engine power supply system or the air supply at the inlet. As a result, the engine runs on an enriched mixture and overspends fuel. The reason may be the need for additional carburetor tuning, malfunctions of the injection, contamination of the air filter.
  3. In the case when the candle electrode is covered with a grayish light soot or white coating, then this color indicates that the engine is running on too lean a mixture of fuel and air.
  1. If it is noticeable that the central electrode of the candle and the skirt were covered with engine oil, as well as unburned fuel was found on the candle, then the cylinder from where the candle was twisted does not work, and it fills the candle itself. As a rule, the motor in this case noticeably troit, loses power, consumes fuel. There can be many reasons for this, from a malfunctioning spark plug or ignition system to serious engine failures (low compression, valve burnout, destruction of piston rings, etc.). The most alarming sign can be considered the presence of small metal particles that adhere to the oily soot. This indicates the destruction or significant wear of any part or element, after which the metal fractions got into the combustion chamber. In such a situation, the engine must be disassembled, carried out troubleshooting and then repaired.
  2. Explicit destruction of the central electrode and its ceramic skirt will indicate that the engine has been operating for a long time under detonation conditions, early ignition is set, fuel with the wrong octane rating is used for a specific type of ICE, or the candle has a poor workmanship, defect or manufacturing defect.

Useful Tips

Having figured out what color the spark plugs should be in this or that case, it is possible to diagnose the internal combustion engine. Separately, we add that it is very important to observe the rule when the motor must warm up and run under loads before twisting the candles.

As already mentioned, to obtain reliable data, you need to drive about 30, or even better two or even three hundred kilometers, along the highway before unscrewing the candles by car. If the condition of the engine is of concern and you need to diagnose the candles and their color, then the following actions will be most correct:

  • pick up new candles that correspond to the recommended physical dimensions and the indicator of the glow number for a specific ICE;
  • refuel high-quality fuel at a proven gas station;
  • after installing the candles, go on a trip along the highway, which will allow you to overcome a distance of at least 30 to 300 km;

Only after these steps can you unscrew the candles, after which their color, soot and condition can judge the operation of the internal combustion engine. It should also be borne in mind that in the CIS, fuel quality is significantly inferior to fuel in European countries. It turns out that the declared service life of any spark plugs, regardless of type, brand, design features (iridium, multi-electrode, platinum, etc.), as well as other differences, is desirable to reduce by 20-30%.

over, a more important indicator is not what color of the spark should be on the candle, but the discharge power and the breakdown depth. At the same time, it is recommended to check the spark plug for performance under conditions of increased pressure in the combustion chamber. There are special stands for such a check, since there are quite common cases when there is a spark during a regular check, but after screwing into the engine there are certain malfunctions.

What does the color of spark plugs mean

Video: What Does The Color Of Spark Plugs Mean


The ignition of the air-fuel mixture in gasoline engines is carried out thanks to automobile candles. Between the electrodes on the head part a spark is formed after applying a high voltage. After prolonged use, contact contamination is possible, so you need to know the causes of soot on spark plugs and get rid of it in a timely manner.

Diagnostic methods

When the normal color of the spark plugs (C3) is lost and a darkening appears in the form of soot, such an event can occur both on one side and throughout the diameter. Problems are possible simultaneously in a single cylinder or can appear in several places at the same time. Also, experienced motorists are able to distinguish the so-called types of dry or wet soot.

It is worth considering the factors on which the occurrence of multi-colored deposits depends:

  • The first signs of a dark coating on the surface of new NW can often occur after 200-300 km of run. You can control the phenomenon when driving on the highway for a long time with a constant speed and load on the internal combustion engine. Thus, it will be possible to obtain objective information about their condition.
  • The amount of dark coating on the surface depends on the quality of gasoline. This forces motorists to look for gas stations offering high-quality fuel, and in no case to pour gasoline or similar liquids.
  • For carburetor engines it is recommended to control the set idle speed.

The use of additives helps to prevent the appearance of black burns.

Types of soot

Diagnostic operations can be carried out independently, based on instructions for replacing candles. It is advisable to conduct them regularly to monitor the condition of the elements of the fuel system. Otherwise, the car will behave negatively while driving, for example, there will be vibrations in the engine compartment, intermittent power, etc.

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It is important to know what color spark plugs should be, which fully fulfill their functions, because unnecessary plaque hiding shiny metal contact surfaces prevents the spark from appearing regularly at the right time.

Before you know what the color of spark plugs means, you need to figure out what varieties of it are. In cars, there are such stains:

The final color is determined by the chemical composition of the mixture burned. An ideal working candle will be one that does not have a plaque or there are small salt whitish deposits, as a result a gray film forms. Also, in addition to shades, there should not be a high density of soot, which often appears in the following cases:

  • low quality fuel;
  • problems working with filters;
  • defective SZ from unscrupulous manufacturers;
  • the mismatch of the physical characteristics of the candles with ICE.

When identifying the causes, it is worth getting rid of them as soon as possible.

White plaque on spark plugs: reasons

As a rule, most motorists with little experience, after twisting the candles out of the combustion chamber, expect to notice tar on the surface. However, in almost every fifth case, its color is whitish.

It is believed that white soot on spark plugs is evidence of poor fuel quality. He can also talk about a reduced percentage of gasoline in the prepared mixture. When this type of by-product has some tactile roughness, then this is a sign of frequent overheating of the internal combustion engine.

If the main reason is dirty gasoline, it is enough to change the gas station and clean the contacts for better sparking. In the second case, you will need to perform some diagnostic work to identify the source of overheating that occurs in such situations:

  • depressurization of the intake manifold, as a result of which more air enters the mixture;
  • candles are installed that do not match this engine;
  • there are problems with the cooling system;
  • malfunctions in the radiator;
  • Ignition calibration required.

A similar shade of yellow occurs due to the high temperature in the combustion chamber. It manifests itself in the process of engine operation at high or maximum possible speeds. The driver is recommended to shift gears in advance, at 4-5 thousand rpm, avoiding unreasonable heating.

Red soot

If red spark plugs appear after twisting, then this type will be in most cases low-hazard. The tonality of the surface is manifested in half the cases and is explained by the presence of active impurities or additives in the mixture, which, for example, contribute to a better ignition of the composition or protection against possible corrosion processes.

The presence of red-red tones is a sign of a large amount of fuel and the presence of oily elements in the mixture. Saturation of burgundy is a case associated with low-quality gasoline, in which there is an abundance of improving additives. Light similar tones correspond to better gasoline quality.

Having revealed a similar tone on the candle surface, you should not go to repair the car. It is enough to change the candles, change the oil and refuel at another gas station.

What Does The Color Of Spark Plugs Mean

Black carbon

This type of carbon deposit is one of the most dangerous. If there are signs of soot on the surface of the candles, we recommend that you go through a diagnosis in a car service to know the condition of the car exactly.

The abundance of black particles occurs in case of problems with the motor in 90% of cases. Their presence indicates an excess of fuel in the resulting mixture, which contributes to the rapid wear of the main components and mechanisms of the internal combustion engine. Experienced experts assure that the presence of such pollution indicates not only the imbalance of the engine, but also problems with the engine.

Traditionally, there are two varieties of soot:

In the first version, the proportions of fuel and air are unbalanced, which are the result of such processes:

  • carburetor breakage or clogging;
  • enrichment problems;
  • lower air filter patency, which leads to insufficient penetration of air into the mixture;
  • reduced compression;
  • problems with candles, leading to unstable sparking.

In the second embodiment, when detecting oily contaminants with blackish-brownish tones, the probability of penetration of engine oil into the combustion chamber is high. Inside the cylinder, the lubricating fluid does not completely burn out due to its physicochemical properties and insufficient combustibility. Penetration occurs in most cases due to the loss of quality of the piston rings and valve caps.

Brown shade of soot

A similar type of carbon deposits can occur after absolute immersion of the head with contacts in gasoline. Thus, fuel completely fills the area of ​​sparking and blocks the occurrence of flame.

It will be possible to minimize or completely eliminate the problem after eliminating excess moisture. Most often, the problem arises from clogging the carburetor with poor-quality fuel or poor-quality additives.

What does the color of spark plugs mean

Some useful information about spark plugs taken from the Internet. Of course, many know this, but for some it will come in handy.

What can the twisted candle and its color say
There are many ways to diagnose the condition of a car engine. Among the most commonly used can be called computer diagnostics, compression measurement, and others, but most of them require special equipment. Nevertheless, there is a sign by which it is fairly accurate to determine how well the engine works, without the use of additional tools. this is soot on spark plugs. The appearance of an inverted candle can tell a lot about the state of the power unit and the correct operation of the auxiliary systems.

Common mistake
To obtain a reliable result, you need to conduct an inspection after the engine has been running for a long time. Otherwise, the result of the inspection will allow to make erroneous conclusions. Quite often there is a situation when drivers start a cold engine in winter and, having heard the sound of its uneven operation, turn off the candles and turn out the candles.
When they see black soot, they make premature conclusions about the malfunction of the power unit, forgetting that black soot can form due to the fact that at low temperatures the working mixture is enriched forcibly, and because the engine is not heated to the optimum temperature, it does not have time to completely burn out. The unstable operation may well be explained by the malfunction of high-voltage wires, which must be replaced for a long time.

How to
Thus, in order to get a reliable result, it is best to drive at least two hundred kilometers with obviously clean working spark plugs. In this case, the probability of error is almost completely eliminated.

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Many modern cars use iridium or platinum candles. They are distinguished by a thin central electrode (about 0.4 mm). They have to be changed once every hundred thousand kilometers, and thanks to the small diameter of the central electrode, a spark forms almost in the same place, of the same force.

Spark plug color

Normal condition
If everything is in order with the car’s engine, then there will be little deposits on the insulator, and its color can vary from light brown to coffee. There can be no trace of oil on the candle. The electrode burns out moderately. In the case of an iridium candle, even burnout is likely to go unnoticed.
Any other color and condition of the candle is a deviation from the norm and requires increased attention.

The black
If the insulator and electrodes are covered with a velvety black soot, this indicates that the power system is preparing an excessively rich mixture. The extent to which soot is strong indicates the degree of re-enrichment of the working mixture. The reasons are that the carburetor is incorrectly adjusted, or the electronic control unit for the injection engine malfunctioned (for example, the air filter is clogged, the oxygen sensor is out of order, or the air damper drive mechanism is faulty). This phenomenon is accompanied by increased fuel consumption.

Light gray white
The light gray or white color of the insulator indicates that the motor, on the contrary, runs on an excessively lean mixture. If timely measures are not taken to eliminate the problem, then overheating or melting of the spark plugs, or overheating of the combustion chamber, which will subsequently lead to burnout of the exhaust valves, will follow. The reasons for the appearance of such a deposit can be different: too low a glowing number (“hot” candle), the use of low-octane gasoline, and a large ignition timing. It is also necessary to pay attention to whether a phenomenon such as glow ignition is manifested, if it takes place, therefore, the candles overheat during operation.

Brown red
Brown or red soot on the insulator, comparable to the color of red brick, appears due to the operation of the motor on gasoline containing compounds of lead or other metals. These compounds are added to the fuel as additives to increase the octane rating. If the engine has been running on leaded gasoline for a long time, a brown conductive coating forms on the surface of the insulator, as a result of which normal sparking is disturbed.

Candle oil
The next option. soot with traces of engine oil on the candle. As a rule, after a long standstill, the motor for the first time after starting is troit, and the exhaust gases have a white-blue color. After warming up, all symptoms disappear. The increased oil consumption complements the picture. Such signs indicate improper temperature in the cylinder. The reasons for the formation of oily soot are too “cold” candles (with a large glowing number), wear of piston rings, valve stem seals or valve guides.

It may also happen that the turned-out candle does not have either a central electrode or an insulator. This occurs as a result of prolonged operation of the engine with detonation, the use of low-octane gasoline, ignition too early or factory defects. Concomitant symptoms are similar to the case described above. If the circumstances are successful, debris of the electrode and insulator will fall into the exhaust system and will not get stuck between the valve and the seat; otherwise, the cylinder head must be repaired or replaced.

Fly ash
The candle can be covered with ash deposits, their color does not matter (soot can be white, gray or black). This is due to oil entering the combustion chamber. The reasons for the formation of such a deposit are stale rings or the development of a cylinder. As an accompanying sign, there is an increased oil consumption, a strong blue exhaust with a characteristic odor similar to a motorcycle one.

Erosion
With long-term operation of candles without replacement, traces of erosion noticeably appear on the side and central electrodes, while the insulator can have white, brown or coffee color. The motor of the car is continuously troit, does not develop full power, unstable idling. The reasons for this are non-compliance with the intervals for replacing spark plugs or the use of gasoline containing tetraethyl lead. Lead compounds cause chemical reactions in the cylinder, resulting in rapid destruction of the electrodes.

Gasoline by candlelight
Finally, the last case when an inverted candle turns out to be filled with gasoline. If it is not twisted immediately after starting the engine in frost, this indicates that the ignition system, carburetor or injector are faulty. You can try to blow out and dry the candle, if the picture repeats, you have to do the repair.

What does the color of the spark plugs mean, and what color should they be? Your auto pulse

What does the color of the spark plugs mean, and what color should they be?

What does the color of the spark plugs mean, and what color should they be? To answer this question, you need to check them correctly. Novice drivers usually make 2 mistakes in this test:

    Cold engine test. Having unscrewed a candle on a long-shut off engine, it is far from always possible to determine the correct color, for example, during this time gasoline completely dries out;

For a correct assessment of the state of candles, you need to not only warm up the car, but also drive about 5 kilometers on it. In this case, you can accurately assess the performance of this ignition element.

Candle color. First you need to determine how the candle should look in normal condition. First, it must be dry. Its color should ideally be light sand. But, at the same time, darkening of the electrodes to a coffee color is possible. It should not have any oil drips and soot. Light burnout of the electrode is possible. On the iridium candle, even this can not be seen. Any other candle condition is cause for concern.

Outwardly, it looks like a partial or complete destruction of the electrode. Partially damaged, there is an electrode on old candles. This is a completely natural occurrence at the end of the life of the candle. Another case is the complete destruction of the electrode. This happens when the engine is operated in detonation conditions. In this case, it simply collapses due to explosive loads. In the best case, this happens in small fragments with their complete burnout. Sometimes the electrodes fall off immediately and get stuck in the exhaust valve, this leads to the need to repair the cylinder head.