Spark plugs: whose spark is more powerful? What can be understood by the color of spark plugs when checking Spark plug color.

30.09.2019

Spark plugs are the most important part that is necessary for work. The main task is the formation of a spark in the combustion chamber, due to which it is possible to realize the 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, increased fuel consumption is noted, reactions to pressing the gas pedal slow down, the power unit starts to work unstably, troit, has toxic exhaust, etc.

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

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 spark plugs should be, as well as what color of spark plugs, which means and what engine failures indicate in one case or another.

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Different color spark plugs: what does it indicate

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 necessary to start inspecting the candles only after the engine has warmed up well and reached operating temperatures, and also worked in a loaded mode before inspection.

In other words, the car should drive at least 20-30 km. At the same time, candle diagnostics can be considered the best approach after a long drive along the highway, when the car has traveled at least a couple of hundred kilometers.

So, let's look at the meaning of the colors of the spark plugs, which can be seen after they are unscrewed on various internal combustion engines. To begin with, the normal color of a spark plug is when the skirt of the center electrode is light brown, there is practically no carbon deposits and various deposits. There should also be no smearing visible. This color of 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 or.
If, after unscrewing, it is clear that black fluffy soot has accumulated on the central electrode, then this indicates problems with or air supply to. As a result, the engine runs on an enriched mixture and overuses fuel. The reason may be the need for additional, malfunctions, pollution.
In the case when the spark plug electrode is covered with a grayish light soot or white coating, then this color indicates that the engine is running on a too lean mixture of fuel and air.
In such a situation, it is necessary to diagnose the internal combustion engine in depth, since a lean mixture in loaded modes leads to severe overheating of the spark plug and the entire combustion chamber. As a result, these overheatings can cause. If the spark plugs are white, the reasons may be in disturbed carburetion processes, excess air may be sucked in, sensors may malfunction, etc.
In no way should one forget that a low glow number of candles or poor fuel quality, as well as early ignition, can lead to the fact that the central electrode and the area near it will be covered with a white coating. In parallel, it should be borne in mind that ICE malfunctions and engine operation at critical temperatures can also be the cause of the formation of such a white coating.
The color of soot on spark plugs, which is more like a brick color (has a shade close to brick red), indicates that the power unit is running on fuel with an excessive amount of metal-containing additives in its composition. At the same time, it is important to know that red spark plugs will not be able to work properly in the engine over time, since the deposition of heavy metals (for example, lead) on the spark plug insulator begins to conduct current. As a result, the spark does not pass between the electrodes, and the element itself loses its performance.
It is also possible to make a diagnosis of the unit and determine its condition by the color of soot if, after turning out the candles, traces of engine oil are visible in the thread area. As a rule, in this case, the engine starts with great difficulty, troit on a cold one, although after warming up the internal combustion engine with oily candles, it starts to work more or less stably. After turning out, the lubricant gets on top of the thread of the candle, but this does not mean that it is initially oiled in the lower part.
In any case, the presence of fresh oil on the spark plug and in the combustion chamber may indicate problems with (oil seals) and indicate other malfunctions. Such a motor without repair will start badly, “eat” oil and. Note that sometimes they lead to the fact that oil accumulates outside, that is, in candle wells.
In such a situation, it is necessary to additionally check the candle wells for filling with lubricant, which will help to avoid inaccurate and hasty conclusions in the future.

If it is noticeable that the central electrode of the candle and the skirt are covered with engine oil, and unburned fuel is found on the candle, then the cylinder from which the candle was unscrewed does not work, but. As a rule, in this case, the engine noticeably troit, loses power, consumes fuel. There can be many reasons for this, ranging from a malfunctioning spark plug or ignition system to serious engine breakdowns (low compression, valve burnout, destruction, etc.). The most alarming sign can be considered the presence of small metal particles that stick to oily soot. This indicates the destruction or significant wear of any part or element, after which the metal fractions entered the combustion chamber. In such a situation, the engine must be disassembled, troubleshooted and then repaired.
Obvious destruction of the central electrode and its ceramic skirt will indicate that the engine has been operating for a long time in conditions, early ignition is set, fuel with an unsuitable octane rating for a particular type of internal combustion engine is used, or the candle has poor workmanship, marriage or a manufacturing defect.
Naturally, in this case, the cylinder does not work, the motor troit, etc. The risk of spark plug failure is that broken parts can get stuck under the exhaust valve and cause other more serious damage. The result in this case will be the need for repair.
Abundant accumulation of ash deposits on the candle, regardless of the overall color of the soot, indicates that the oil is consumed for waste in the combustion chamber. The most common reason is. In case of problems with the rings, an increased oil consumption is observed, in the gas recirculation mode, the exhaust acquires a bluish tint, the smoke becomes oily. It is enough to bring a sheet of clean white paper to the exhaust pipe and turn it off at idle, after which greasy oil stains remain on the sheet.

Having figured out what color the spark plugs should be in a particular case, you can diagnose the internal combustion engine. Separately, we add that it is very important to follow the rule when, before unscrewing the candles, the engine must warm up and work under load.

The fact is that if, immediately after a cold start, malfunctions or failures were noticed in the operation of the engine, and then the candles were unscrewed to check, then in many cases you can see gray-black soot. At the same time, such carbon deposits do not yet mean that the engine has a problem associated with the constant formation of just such deposits, malfunctions in mixture formation, etc. Simply put, at the time of a cold start, the mixture is enriched. It turns out that the malfunction, for example, lies in the ignition system, and black carbon deposits and flooded candles do not indicate problems with the power system (injector or carburetor).

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

select new candles that correspond to the recommended physical dimensions and glow number for a particular internal combustion engine;
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 cover a distance of at least 30 to 300 km;

Only after these actions can the candles be unscrewed, after which one can judge the operation of the internal combustion engine by their color, soot and condition. It should also be taken into account that in the CIS the quality of fuel 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, it is desirable to reduce by 20-30%.

It is important to understand that although many manufacturers guarantee the normal operation of candles for about 30 thousand km, taking into account the quality of domestic fuel, this figure in practice may not exceed 15-20 thousand km. For this reason, it is recommended that in parallel with each scheduled maintenance (10 thousand km), unscrew the candles to check them, as they may need to be cleaned of carbon deposits, adjust the gaps, or even replace them prematurely.

Finally, we add that the color of the spark on the spark plug can also partially indicate the presence of problems with the candle itself or the ignition system. Ideally, the discharge should be stable and also have a rich, bright blue color. It should be noted that the color of the spark on the spark plug can also change from reddish to white or yellow.

In this case, a more important indicator is not what color the spark should be on the candle, but the discharge power and the breakdown depth. In parallel, it is recommended in 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 normal check, but after screwing it into the engine, certain failures occur.

What are the advantages of multi-electrode candles? Is it true that there are more sparks on them than on “ordinary” ones?

Let's immediately dispel the tenacious myth about "multi-spark" candles: they do not exist in nature. There can be any number of side electrodes, but the spark discharge is always the same. Vendors often demonstrate the "multi-spark" mode on the stands, which gives the impression of a simultaneous discharge in the form of a glowing ring, but this is just an optical illusion, like in the movies.

As for the advantages of multi-electrode candles, they are. The first is the resource: due to the distribution of the load between the side electrodes, the rate of their erosion is reduced. By the way, that is why they are often installed in engines with difficult access to candles. The second is the presence of the so-called "open spark", in which the flame front does not get stuck in the interelectrode space, but goes into the combustion chamber. The combustion rate increases, which slightly increases the power of the motor and improves its efficiency. The third advantage is a relatively small number of fakes of such candles.

Flaws? Relatively high price plus the inability to set the desired interelectrode gap ...

Why do we need all sorts of "jewels" such as iridium electrodes?

A resource of 90–100 thousand km for such candles is a common thing.

Then, the service life of iridium, platinum and other “thoroughbred” candles is several times higher than that of “mongrel” ones ... At the same time, refractory electrode materials make it possible to increase the field strength in the interelectrode space, while at the same time clearing the way for the flame front. And a more powerful spark discharge, among other things, contributes to a good self-cleaning of the candle.

Why do pre-chamber candles not take root?

That which has obvious advantages takes root. In particular, a kind of "microprechambers" - recesses in the electrodes of individual branded candles - contribute to the stabilization of the discharge at the edges of such recesses. Such recesses can be both on the side (Denso) and on the central (NGK) electrodes. At the same time, there is a certain technical effect.

As for the "full-fledged" prechamber candles, they are often used in the engines of Formula 1 sports cars. The fact is that such engines operate at high speeds, at which ventilation problems simply do not arise. But at minimum idle speed, and even at low loads, the mixture in the cylinders moves much less intensively, and therefore the inner chamber of the candle actually suffocates. This is exactly what is observed, as a rule, when trying to stupidly install something pseudo-sports on your engine.

What gap should the spark plugs be?

Complex issue. The number one authority in this matter is the manufacturer of the car, more precisely, the engine. True, today such recommendations are addressed only to servicemen: the consumer is blocked by all means from access to the engine compartment (and, in general, they do it right).

Another thing is funny: even the recommended gap cannot be the same for all types of candles. For example, for the same iridium, it can certainly be more than for the classic ones! But no one usually gives such recommendations. Therefore, its specific value is always individual for the candle-motor tandem. In the general case, the larger the gap, the stronger the spark and ignition source. We also add that with an increase in the gap, the probability of shorting the electrodes by soot bridges decreases.

The danger of an excessive increase in the gap is obvious: the larger the gap, the greater the required breakdown voltage. And the discharge doesn’t care where to “shoot”: it can also pierce the coil if it decides that it’s easier for him ...

What are plasma candles?

We don't know... The question rests solely on terminology, because any spark discharge can be called cold plasma. Therefore, the attempts of individual manufacturers to call their candles plasma is a consequence of illiteracy, as well as the desire to play on the inexperience of consumers. All candles are either plasma or not: the appropriate terminology simply does not exist. But to call only candles of our own production as plasma, without honoring our colleagues in the shop with the same, is simply incorrect.

Why are candles getting thinner and thinner? Even the turnkey size used to be 21 mm, and now it is 14.

Candles with M14x1.25 threads and a large hexagon were used on engines with two valves per cylinder. At the same time, the candle most often approached the combustion chamber from the side and there was plenty of space to place it. On modern engines with four or even five valves, the only place to place a spark plug is in the center of the combustion chamber. The candle is screwed into the cylinder head through the candle well, which "steals" the space from the valves and the jacket of the cooling system. That is why it is necessary to make more and more thin candles and small diameter wells.

The spark plug pulled out of the engine is covered with a layer of oil. What is the reason?

Oily spark plugs can be a sign of relatively easy to fix problems, such as too high engine oil or clogged crankcase breathers. But it could be caused by much more formidable problems, such as worn piston rings, broken valve guides, and faulty valve seals.

It was possible to turn out the candle with great difficulty, and the new candle does not screw in completely. What to do?

It is obvious that the previous candle was not wrapped in the cylinder head. Therefore, part of the thread in the head is covered with soot and does not allow a new candle to be screwed in. In such a situation, it is best to make grooves along the threaded part of the old candle with a needle file. This will turn the candle into a kind of tap. Further, having applied a thin layer of grease to the thread of the candle, we screw it into the hole, periodically “handing it back” until we go through the entire thread. We wipe the candle hole with a swab of lint-free rags and screw in a new candle. It is advisable to use a special high-temperature lubricant or simply rub the threads with graphite.

The insulator of the candle has acquired an incomprehensible reddish color, although there is practically no soot. What is this?

Red soot on a candle is formed during the combustion of gasoline with a high content of iron-containing additives based on ferrocene. Unscrupulous manufacturers use these additives to increase the octane number of gasoline. The additive is not useful for both candles and the engine. Seeing this color of a candle, think about changing the gas station.

Should I clean the spark plugs between changes?

With a working engine, there is little carbon deposits and cleaning of the candles is not required. If the candles are covered with abundant soot during short runs, then this is an occasion to repair the engine, and not to clean the candles. In addition, the threaded holes for the candles are made of aluminum, and countless twisting and screwing can lead to thread stripping.

Fellow car enthusiasts, tell us, have you met with any unusual defects in candles?

The quality of the spark on the spark plugs is checked in the same way as in its absence. However, it is desirable to change the gap between the high-voltage wire of the spark plug and the mass. A spark is considered good if it penetrates a gap of at least 7 mm.

A malfunction that occurs as if it does not exist at all, but it is much more difficult to find the cause of its occurrence. An ammeter will not even be able to help in this case. The best way to determine a malfunction is to turn off one or another device or section of the circuit from the ignition system and try, if possible, to get a spark without them. The appearance of a good spark indicates a malfunction of the switched off device.

When, after checking, it turned out that the spark between the spark plug and the high-voltage wire is weak, the distributor is turned off from the ignition circuit and the quality of the spark between the ground and the high-voltage wire of the ignition coil is checked. The presence of a strong spark indicates that the entire ignition system to the distributor is working, except for the distributor cap, rotor or high-voltage spark plug wires. If these parts are cracked or damaged, they must be replaced.

If, when the distributor is turned off, the spark, as before, is weak, you should carefully check all the clamps of the low voltage current circuit, cleanliness and reliability of fastening. If, even after checking the clamps, the spark is weak, it is necessary to turn off the breaker from the low voltage circuit. Its action can be replaced by an additional wire, one end of which is connected to the connection point of the capacitor wire with the low voltage wire coming from the P terminal of the ignition coil, and the other end is sharply struck by mass. In this case, the wires of the ignition coil and the capacitor must be disconnected from the terminal K of the breaker.

The occurrence of a strong spark between the ground and the high-voltage wire of the coil without the action of the breaker indicates a malfunction of the breaker.

To control the safety and reliability of the contact and isolation of the current-carrying parts of the circle from the mass, you need to check the inner circle of the breaker, the condition and gap in its contacts on all cam protrusions. When checking the inner circle of the breaker, find out whether the cam, bushings of the breaker roller, the axis and the hole for the axis of the breaker lever did not work out, the breaker panel is securely seated on the bearing.

If the spark is weak and irregular when the breaker is off, then the capacitor or ignition coil is most likely faulty. After making sure that the capacitor is working, you should check the serviceability of the ignition coil. Strong heating of the ignition coil indicates a short circuit in the primary winding. Replace the defective coil.

Even on modern cars equipped with an abundance of electronics and injection units, problems regularly arise. This is due to the operation, and there's nothing you can do about it. Most often, car owners are advised to learn how to check the spark on the injector, because its disappearance leads to difficulty starting and unstable operation of the motor.

At the same time, it is important to know that checking with your own hands is good, but you can get a strong charge of electricity, ruin the ignition module or controller if you do not know all the intricacies of diagnostics.

spark test

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The ideal result is when a bright blue color comes from the candle. In all other cases, when the color is white, red or another, the system is not all right. The spark must be powerful, confident, appear constantly, and not periodically. The spark should not be pink either.

If there is no spark at all, and the distributor is fully functional, it is recommended to check the candle itself directly. For example, you can install a known-good spark plug instead of a checked one.

On the injector, often, if the engine runs intermittently in XX mode or its power decreases significantly, it is customary to talk about problems with candles. Important information can be provided by the Check Engine indicator.

Checking a module with a tester

The module on the injector does not apply to nodes that constantly break or cause trouble. However, in some cases, problems with it are noted. For example, if the winding is damaged, a breakdown of the insulation layer is observed, which ultimately leads to a short circuit. Also, the bobbin (module) can easily fail if the candles or armored wires are faulty.

This is a simple verification option. You need to take a tester, connect one of its terminals to the module contact marked A, and the other end to ground (any part of the car body). Start the engine and look at the tester readings.

The module is fully functional if the device shows 12 V.
All other values, up to their absence, indicate malfunctions (it is also recommended to check the fuses).

spark color

Thus, the following conclusions can be drawn from the color of the spark from candles.

If the color is white with a blue tint, the spark is constant, then everything is fine.
If the spark is purple or transparent, colorless, it can be concluded that the module, distributor or armored wires are damaged. Such a spark is knocked out at intervals or appears 1-2 times when checking.
Red or yellowish color indicates the presence of additives in the fuel.

Candles

The appearance of the spark, its color, is also influenced by the candle itself, its condition.

Table: condition and appearance of candles

Candle condition	Decryption
Normal candle - the color of the deposits on the insulator (the skirt of the central electrode) is light brown or coffee; soot and deposits are minimal. Complete absence of traces of oil. Moderate electrode burnout.	The owner of this engine can only be envied, and there is something - this is economical fuel consumption and no need to add oil from replacement to replacement.
The central electrode is covered with velvety black soot - dry soot. A typical example of a spark plug from an engine with increased fuel consumption.	Rich air-fuel mixture - injector malfunction - malfunction of the engine control system (for example, failure or incorrect readings of the oxygen sensor), malfunction of the air damper drive mechanism, clogging of the air filter.
The color of the electrode is from light gray to white.	An example of an excessively lean air-fuel mixture.
The skirt of the central electrode of the candle has a characteristic reddish hue, this color can be compared with the color of red brick.	This reddening is caused by the operation of the engine on fuel containing an excessive amount of additives containing metal. Long-term use of such fuel will lead to the fact that metal deposits form a conductive coating on the surface of the insulation, through which it will be easier for the current to pass than between the electrodes of the candle, and the candle will stop working. Such a plaque on a candle is most typical when using manganese additives in gasoline, which are used to increase the octane number of fuel.
Pronounced traces of oil - black oily soot, especially in the threaded part.	As a rule, this indicates an incorrect temperature regime in the direction of insufficient spark plug temperature or engine oil getting into the cylinder. Possible malfunctions: incorrect selection of a candle (too "cold" candle), wear of valve guides, valve stem seals, piston rings. There is increased oil consumption. In the first minutes of engine operation, at the time of warming up, a characteristic white-blue exhaust.
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 breakage of the partitions between the piston rings with the ingress of metal particles between the valve and its seat. In this case, the engine "troits" without 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.
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 number, very early ignition, and - just a defective spark plug. The 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 getting stuck under the exhaust valve, otherwise repair of the cylinder head cannot be avoided either.
Destruction of the ceramic insulator.	Causes of occurrence: a sharp change in temperature, for example, when cooling a candle unscrewed from a hot motor in cold water. In some cases, destruction can be caused by a defect in the candle itself (marriage or fake), or mechanical damage, for example, as a result of a fall.
The spark plug electrode is overgrown with ash deposits, the color does not play a decisive role, it only indicates the operation of the fuel system.	The reason for this build-up is the combustion of oil due to the development or occurrence of oil scraper piston rings. The engine has increased oil consumption, when regassing from the exhaust pipe, there is a strong, blue smoke, the smell of the exhaust is similar to that of a motorcycle.
Splashing spark plugs with gasoline.	Often occurs due to a malfunction of the injector. In winter, it can occur due to the fact that gasoline that has entered the combustion chamber does not have time to evaporate and settles on spark plugs and cylinder walls.

Detailed tips for checking the ignition system.

Try not to crank the engine with the ignition on and at least one high-voltage wire removed!

The fact is that the ignition coil, when the current in its primary circuit is interrupted, creates a voltage in the secondary circuit. It is limited by the breakdown voltage in the candle, i.e. voltage at which a spark occurs.

If you remove the high-voltage wire, then the high voltage is not limited, and there is a very high probability of electrical breakdown in another place, for example, the cover of the distributor. Therefore, it is necessary to check the spark on the candles of Japanese cars with their delicate electronics as follows. Unscrew all the candles and tie them with bare wire, for example, aluminum, in a row. Fasten the free end of the wire to the "mass", i.e. screw it to any unpainted part on the engine, and put all the tips of high-voltage wires on the candles.

Now, scrolling the engine with a starter, you can observe a spark on all the candles. If the spark is very thin (filamentous), it can be argued that the switch has failed. If the candles are dirty and wet, they must be cleaned, but it is better to replace them with new ones. Set the same gaps on the candles. The larger the gap in the candles, the better the combustible mixture in the cylinders will be ignited, but the higher the probability of failure (electrical breakdown) of any elements of the ignition system. Turn the starter 10-20 revolutions.

The spark should jump only between the central and side electrodes (in the same place), be thick, click loudly and be purple. If each electric discharge will at least by some sign differ from the previous discharge and from the discharges on neighboring candles, then it is necessary to look for the cause, because. this indicates a malfunction (in this case, the engine may start, but it will work unevenly).

Now set a gap of 2-4 mm on one candle and again turn the engine with a starter. If there is no spark on a candle with a large gap, or it changes in power with each click, then the ignition coil is most likely faulty. Another reason may be that there are leaks in the high-voltage part of the system (cracks, breakdowns, etc.).

Measure the electrical resistance of the wires. It should be about 5 kΩ and not differ by more than 1 kΩ from the resistance of other wires. Although many engines work quite tolerably even with a resistance of high-voltage wires of about 15 kOhm. Very often, the reason for the lack of spark is the failure of the switch.