What does the color of spark plugs mean: white, black, red

For full operation of a gasoline internal combustion engine, at least two conditions are necessary. This is a timely supply of fuel and a spark that will ignite the combustible mixture.

The fuel system is responsible for supplying fuel to the combustion chamber, and the ignition system is responsible for the appearance of a spark, where, of course, spark plugs are the main igniter of gasoline. It follows that both of these systems must always be in good condition.

To better understand the problem of spark plug failure, let’s take a short look at their design.

The fresh ignition unit is a metal body with a hex key (there are different sizes), and a threaded part, at the end of which there is a “negative” electrode. Inside the housing itself there is a “positive” electrode (often copper), which is separated from the steel housing by a ceramic insulator. At the top of the steel electrode there is a thread onto which a shaped nut is screwed for a reliable connection with the high-voltage wire. At the bottom, the electrode protrudes from the insulator body. Between the “positive” and “negative” insulators there is a required gap specified by the manufacturer, in which a spark appears.

Proper performance of the spark plug will continue until there is no carbon deposits on the spark plug and no traces of oil. Also, if the integrity of the insulator is not compromised or the gap remains unchanged. For example, if the insulator bursts or splits, the voltage will partially or completely go to ground, in which case the spark plug begins to work intermittently or fails altogether. As a result, the engine begins to “triple” and loses its power.

The same phenomena will occur if there is no gap between the electrodes. Motor oil is also a good conductor, as a result of which, if there are oil leaks on the spark plug, the spark will go along the shortest path to ground.

Brick candle

When diagnosing an engine using spark plugs, you can also see a red part. Typically, such deposits accumulate on the skirt of the central electrode. Such a spark plug does not indicate a malfunction in the engine. The presence of red carbon deposits tells the car owner that it is time to change the gas station. This deposit occurs due to low-quality fuel, which contains metal-containing additives.

If you drive this kind of gasoline regularly, then a layer of deposits will form that can conduct electricity. And the spark, which should jump between the electrodes, will strike in a different place. The candle will simply fail and can only be thrown away. Fuel with a high content of such additives may eventually damage the ECU, as well as the lambda probe and catalyst.

Spark test

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It is recommended to test the spark in a dry room, such as a garage. There is no need to use any additional devices or complex equipment.

The ideal result is when the candle emits a bright blue color. In all other cases, when the color is white, red or another, there is something wrong with the system. The spark must be powerful, confident, appear constantly, and not periodically. The spark shouldn't be pink either.

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

On an injector, if the engine runs intermittently in idle mode or its power noticeably decreases, it is customary to talk about problems with the spark plugs. The Check Engin indicator can provide important information.

Common mistake

To obtain a reliable result, the inspection must be carried out after the engine has been running for a long time. Otherwise, the inspection result will allow you to draw erroneous conclusions. Quite often there is a situation when drivers start a cold engine in winter and, hearing the sound of its uneven operation, turn off the spark plugs and turn them out.

Seeing black carbon deposits, they draw premature conclusions about the malfunction of the power unit, forgetting that black carbon deposits can form due to the fact that at subzero temperatures the working mixture is forcibly enriched, and due to the fact that the engine is not warmed up to the optimal temperature, it does not have time to burn completely . Unstable operation may well be explained by a malfunction of high-voltage wires that need to be replaced long ago.

What color should the spark be when using a spark tester?

If I use a spark tester with an adjustable gap set to the correct gap for my vehicle's ignition system voltage, what should the spark look like?

I ask because I have seen conflicting opinions on this issue. For example, this Brigg and Stratton site says:

A bright blue sparkle is best. A yellow-orange spark means weak ignition. Not true. The color of the spark determines practically nothing. The hottest spark is ultraviolet, which we cannot see. The blue spark is cold compared to ultraviolet. The orange and yellow come from sodium particles in the air ionizing at the high energy of the spark gap.

However, they are talking about small air-cooled engines and use a special Briggs and Stratton fixed-gap spark tester for small air-cooled engines, model 19368.

Here's another person who says the color of the spark doesn't matter:

I can note that very fast, very high voltage sparks in modern systems are usually not blue. Your mileage may vary.

This poster on another site answering a similar question to the Briggs and Stratton quote above states:

On an automobile ignition system, the spark should be bright blue. This is because the compression ratio is higher than that of a small air-cooled engine. A car engine operates under short-term conditions where the RMP changes, so the fuel demand changes. Where most small air cooled engines operate in a static or steady state.
The compression ratio of the engine and the amount of fuel supplied can affect how well the spark plug fires. This is called spark extinction. A low compression engine running at steady state with a constant supply of fuel will not extinguish even a spark plug with a yellow spark. But on a car engine with a higher compression ratio and under transient conditions, the yellow spark may go out, causing a misfire.

Here's another guy saying basically the same thing:

The recommended 7/16" clearance has always worked for me on outboards. I use mine in the line between the spark plug installed in the engine and the spark plug wire. This means the spark must cross the 7/16" gap and spark gap in the engine while running. You can then also rev the engine to test the spark at higher speeds. My experience has been a strong blue spark with noticeable noise when firing healthy. The gap is determined by the amount of voltage generated by the ignition, the spark plug gap and the compression ratio. Most manuals provide air gap recommendations for spark testing. The high pressure air/gas mixture creates a much tighter gap for the spark to jump and then escape.

I don't have the experience to tell who is right and I was wondering if anyone more knowledgeable could give me confirmation.

Regarding note 7/16, it is about 1.1 cm, and the breakdown voltage of air at sea level is about 30 kV/cm. It should also be noted that this answer about the physical stack exchange says that the blue color of air sparks occurs from the ionization of nitrogen atoms.

Another interesting point is that the strength of light is inversely proportional to its wavelength, meaning that blue light is about 40% more powerful than orange light, depending on the wavelength ratio.

In fact, someone else asked a very similar question about the physics stack exchange:

Are they a visual difference between air gap sparks of the same voltage but different current?

Has anyone had personal experience of seeing a yellow/orange spark, doing a repair, and then seeing a nice strong blue spark with the performance issue gone?

The main symptoms of engine malfunctions that affect the condition of the spark plugs

This candle is covered with black soot. A typical example of an engine operating with increased fuel consumption (fuel-air mixture too rich). Possible causes: incorrectly adjusted carburetor or faulty injector, faulty air damper, clogged air filter (due to lack of air, the mixture is more intensely enriched with fuel).

This candle is coated with oil. This indicates insufficient heating of the spark plug or engine oil getting into the cylinders. Increased oil consumption is characterized by a white-blue exhaust when warming up. Possible causes: wear of valve guides, valve stem seals, piston rings, cylinder liners.

This is a typical example of a lean air/fuel mixture. Driving with such a mixture leads to overheating of the engine and can cause valve burnout. Overheating of spark plugs is characterized by the engine's reluctance to stall even when the ignition is turned off. Probable causes: too much ignition timing, low octane number of fuel.

In this picture you see a candle covered with metal deposits. This occurs when using gasoline with a high content of additives that increase the octane number. This layer has the color of red brick and has electrical conductivity properties when operating in a cylinder. This leads to the fact that the spark disappears, since the current will not jump between the electrodes, but will pass through this layer.

This spark plug was unscrewed from a faulty cylinder; metal fragments and drops of engine oil are visible on the spark plug. This usually happens when the partition between the piston rings breaks or when a valve malfunctions. In this case, the engine keeps running, fuel consumption almost doubles, engine power decreases noticeably, and there is only one way out - repair.

In the figure we see a spark plug whose electrode is overgrown with ash deposits. In this case, the engine eats oil (it burns in the cylinders). When you change the gas, thick blue smoke comes out of the exhaust pipe. The cause may be worn out oil scraper rings or used up engine oil.

In the photo we see a candle filled with gasoline. In this case, sparking is disrupted, which makes starting the engine impossible. This usually happens when there is no spark between the electrodes or the mixture does not want to ignite (usually happens when starting the engine in severe frost). In this case, you should unscrew the spark plugs, heat them over a fire and clean them with a wire brush.

Monitor the condition of the spark plugs every 10,000 kilometers, or better yet, replace them. This concludes the article. No nail, no rod!

Candles

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

Table: condition and appearance of candles

Candle condition	Decoding
Normal spark plug - 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 oil traces. Moderate electrode burnout.	The owner of this engine can only be envied, and there is much to be desired - economical fuel consumption and the absence of the 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 high 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, clogged 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 spark plug has a characteristic reddish tint; this color can be compared to the color of red brick.	This redness is caused by the engine running on fuel containing an excessive amount of metal additives. Long-term use of such fuel will cause metal deposits to form a conductive coating on the insulation surface, through which it will be easier for current to pass than between the electrodes of the spark plug, and the spark plug will stop working. This deposit on the spark plug is most typical when using mangene additives in gasoline, which are used to increase the octane number of the fuel.
Pronounced traces of oil are black oily deposits, 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 spark plug (too “cold” spark plug), wear of valve guides, valve stem seals, piston rings. There is increased oil consumption. In the first minutes of engine operation, at the moment of warming up, there is a characteristic white and 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 metal particles getting between the valve and its seat. In this case, the engine “troubles” incessantly, 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, or simply a defective spark plug. The engine operating symptoms 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 repairing the cylinder head cannot be avoided.
Destruction of the ceramic insulator.	Causes of occurrence: a sharp change in temperature, for example when a spark plug removed from a hot engine is cooled in cold water. In some cases, destruction may be caused by a defect in the candle itself (defective or counterfeit), 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 oil combustion due to the wear-out or obstruction of the oil scraper piston rings. The engine has increased oil consumption, when over-gasping, there is strong blue smoke from the exhaust pipe, and the exhaust smell is similar to that of a motorcycle.
Spraying a spark plug with gasoline.	Often occurs due to a faulty injector. In winter, this can occur due to the fact that gasoline entering the combustion chamber does not have time to evaporate and settles on the spark plugs and cylinder walls.

Spark plugs are the most important part that is necessary for operation. The main task is the formation of a spark in the combustion chamber, due to which it is possible to ignite the fuel-air mixture in the cylinder.

Note that any disturbances in the spark formation process lead to the engine beginning to lose power, increased fuel consumption, slower reactions to pressing the gas pedal, the power unit begins to operate unstably, troits, has toxic exhaust, etc.

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

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

Read in this article

Types of soot

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

It is important to know what color spark plugs should be in order to fully perform their functions, because unnecessary deposits that hide shiny metal contact surfaces prevent a spark from appearing regularly at the right moment. Before you find out what the color of spark plugs means, you need to understand what varieties there are.

The following colors are found in cars:

Before you find out what the color of spark plugs means, you need to understand what varieties there are. The following colors are found in cars:

The final color is determined by the chemical composition of the combustion mixture. An ideal working candle would be one that does not have a coating or contains small whitish salt deposits, resulting in the formation of a gray film. 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 equipment from unscrupulous manufacturers;
discrepancy between the physical characteristics of spark plugs and internal combustion engines.

Once the causes are identified, it is worth getting rid of them as soon as possible.

Light electrodes

White or light gray spark plugs in all cylinders are a sign of a lean air-fuel mixture supplied by the injector or carburetor. Moreover, the skirt, area near the electrodes and the threaded part are absolutely dry, without traces of oil.

lambda - the probe incorrectly informs the control unit about the amount of oxygen in the exhaust gases, the reason is sensor wear;
faulty or clogged nozzles;
incorrect carburetor settings or clogged fuel jets;
insufficient pressure in the injector fuel rail;
problems with the idle air control;
air leakage under the manifold or in another place;
unsuccessful chip tuning of the controller made by the owner of the car.

A lean mixture does not pose any particular danger to a running engine, but it does cause discomfort to the driver. The car accelerates slowly, pulls poorly and jerks - there is a lack of fuel. Oddly enough, the phenomenon causes increased gasoline consumption - a car enthusiast who wants to achieve better performance indicators presses the accelerator pedal harder and more often.

Black soot

One common type is black carbon deposits on spark plugs. In this case, the surface is covered with a velvety black coating.

It is worth paying attention to the structure of the candle with black soot. Most often this occurs due to an excessively rich fuel mixture entering the engine.

The most common reasons why black soot appears on spark plugs include:

the air filter is clogged and not enough oxygen is supplied to the engine;
the carburetor or injector is faulty;
low compression ratio;
broken or defective spark plug;
breakdown of the fuel pressure regulator;

Extreme conditions of spark plugs

Metal dust, oil, gasoline

The presence of oil, drops of gasoline and small metal fractions on the electrodes is an indication that the cylinder is not functioning. The culprit is either a damaged valve or broken partitions between the piston rings. Parallel symptoms:

Constant tripping of the engine.
Significant loss of power.
Double increase in appetite.

Destruction of the central electrode with a ceramic insulator

Prolonged operation in detonation mode and low octane fuel are the key causes of the crash.
However, one should not write off defects in the manufacture of the product and incorrect operation of the mixture ignition system. At the same time, the engine runs rough, eats a lot and delivers power poorly. The situation is actually dangerous, especially for internal combustion engines running on propane.

When performing a spark plug inspection and discovering this unsatisfactory appearance, it should be taken into account that electrode particles may become stuck under the exhaust valve. This is fraught with cylinder head repair

Ceramic skirt failure and erosion

The insulator can be destroyed only due to defective or improper handling of the candle. For example, the arsonist was unscrewed from a hot engine and dropped into cold water or simply released from his hands at a certain height.

Erosion occurs due to non-compliance with the spark plug replacement interval and excessive bending of the side electrode. It can also be caused by driving on leaded fuel. In this case the motor:

Doesn't start well.
Functions unstable even after warming up.
Troit.
Misfires.
Does not provide adequate power.

The spark plug is filled with gasoline

This scenario often occurs due to a malfunction of the ignition system or because the carburetor/injector is leaking. It is likely that you will need to clean the injector yourself using special means.

However, in winter this phenomenon can occur due to the fact that gasoline does not have time to evaporate and settles on the electrodes. In this case, the engine will not start until the spark plugs are cleaned in alcohol and properly dried. It is worth drying in a gentle mode so as not to damage the insulator. A hair dryer and high oven temperature are not suitable.

The main reason for the raid

The first thing to consider is that the spark plug is necessary to ignite the mixture of fuel and air. The spark plug inside the cylinder operates under extreme loads in difficult conditions, where various chemical and biological effects are provided - this is the high temperature of the spark and processes during combustion of the mixture.

The main reason for the formation of soot is the chemical reaction resulting from the combustion of the fuel mixture. The reaction leads to consequences such as high temperatures and the formation of decomposition products. After each combustion of the next portion of the fuel mixture, a small amount of deposits settles on the electrodes of the spark plug and the cylinder walls.

Deviations from the norm: types of unhealthy carbon deposits on the “injector” spark plugs

Traces of oil on the threads.
White ash coating.
Red (brick) soot.

This indication is valid for a motor showing signs of a healthy condition. There is no need to look at terrifying photographs of completely black candles with a characteristic fur coat, and even doused with gasoline - this is only extreme evidence that there is nowhere to put off the “capital” any further. However, such machines already have enough signs of imminent failure. For example, the oil pressure lamp is on at idle and operating speeds, unstable idling and various knocking noises.

Oil on candle thread

An oil mark on the threads indicates that oil is constantly present at the top of the combustion chamber. It can accumulate in this area for various reasons:

Leakage of oil seals and wear of valve bushings.
Problems with crankcase ventilation.
Problems with the oil supply to the turbine.

Of course, all this makes sense only if there are no traces of oil inside the spark plug well. If lubricant leaks into the well, then the problem is in the gaskets or sealant between the parts of the cylinder head.

Whitish soot

Ash deposits indicate problems with the piston rings: the oil enters the combustion chamber in small portions and the additives contained in it burn out directly on the spark plug. In fact, the color of soot is not always white or gray. It depends on the shade of the oil additive package and is additionally colored by additives contained in the fuel.

The scientific basis for the appearance of ash deposits is of some interest. During the exhaust stroke, the oil-air mixture passes through the hottest part of the combustion chamber - the spark plug. Everything burns out, except for heavy mineral compounds, which settle in the form of grains. When ash deposits are detected, the first step is to consider the possibility of decoking the rings. Otherwise, oil consumption will only progress.

Red-brown coating

The reason for the formation of brick-colored soot is iron-containing additives, which unscrupulous gas station chains add to gasoline in order to increase the octane number. The duplicate name for such additives is anti-knock. To be fair, it is worth noting that such a gesture is quite rare and mainly after service at a gas station of intra-regional importance with a clearly reduced price for fuel. It is pointless to judge the quality of the spark plug or the condition of the engine by this sign. There is only one piece of advice - change the gas station and that’s it.

Different colors of spark plugs: what does it indicate?

As already mentioned, the appearance of the spark plug allows you to evaluate the quality of operation and general condition of the entire engine, as well as its individual components and mechanisms. Let us immediately note that you need to start inspecting the spark plugs only after the engine has warmed up well and reached operating temperatures, and has also worked under load before the inspection.

In other words, you should travel at least 20-30 km by car. In this case, the optimal approach can be considered diagnostics using spark plugs after a long drive on the highway, when the car has traveled at least a couple of hundred km.

So, let's look at the meaning of the colors of spark plugs, which can be seen after they are unscrewed on various internal combustion engines. Let's start with the fact that the normal color of a spark plug is when the skirt of the central electrode is light brown, there is practically no soot and various deposits. There should also be no visible oiling. This color of working spark plugs indicates the efficiency of the engine, the complete 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 the air supply to. As a result, the engine runs on a rich mixture and overuses fuel. The reason may be the need for additional, malfunctions, contamination.
If the spark plug 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.
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 overheats can cause. If the spark plugs are white, the reasons may be disrupted mixture formation processes, possible leakage of excess air, malfunction of sensors, etc.
We should not forget that a low glow number of spark plugs or poor fuel quality, as well as early ignition, can lead to the central electrode and the area near it being covered with a white coating. At the same time, it should be taken into account that internal combustion engine malfunctions and engine operation at critical temperatures can also cause the formation of such a white coating.
The color of soot on the spark plugs, which is more reminiscent of a brick color (has a shade close to red brick), indicates that the power unit runs on fuel with an excess amount of metal-containing additives in its composition. It is important to know that red spark plugs will not be able to work properly in the engine over time, since the deposit 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 functionality.
You can also diagnose the unit and determine its condition by the color of the carbon deposits if, after removing the spark plugs, traces of engine oil are noticeable in the thread area. As a rule, in this case the engine starts with great difficulty and stalls when cold, although after warming up the internal combustion engine with oily spark plugs begins to work more or less stably. After turning it out, the lubricant gets onto the spark plug thread from above, 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 seal caps) and indicate other malfunctions. Such an engine without repair will have bad oil and... Note that sometimes this leads to oil accumulating outside, that is, in the spark plug wells.
In such a situation, you need to additionally check the spark plug wells for flooding with lubricant, which will allow you to avoid inaccurate and hasty conclusions in the future.

If it is noticeable that the central electrode of the spark plug and the skirt are covered with engine oil, and unburnt fuel is found on the spark plug, then the cylinder from which the spark plug was unscrewed does not work, but. As a rule, in this case the engine noticeably stalls, loses power, and overuses fuel. There can be many reasons for this, ranging from a malfunction of the spark plug or ignition system to serious breakdowns in the engine (low compression, valve burnout, destruction, etc.). The most alarming sign can be considered the presence of small metal particles that stick to the oily soot. This indicates destruction or significant wear of any part or element, after which 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 running for a long time in conditions, the ignition is set early, fuel with an inappropriate octane number is used for a particular type of internal combustion engine, or the spark plug has poor workmanship, a defect or a manufacturing defect.
Naturally, in this case the cylinder does not work, the motor suffers, etc. The danger of spark plug failure is that broken pieces can become lodged under the exhaust valve and cause other more serious problems. The result in this case will be the need for repairs.
Abundant accumulation of ash deposits on the spark plug, regardless of the overall color of the soot, indicates that the oil is being consumed as waste in the combustion chamber. The most common reason is. In case of problems with the rings, increased oil consumption is observed; in over-gas mode, the exhaust acquires a bluish tint, and the smoke becomes oily. It may be enough to hold a sheet of clean white paper to the exhaust pipe and let it idle, after which greasy oil stains will remain on the sheet.

Having figured out what color the spark plugs should be in a given case, you can diagnose the internal combustion engine. We would also like to add that it is very important to follow the rule that before removing the spark plugs, the engine must warm up and operate under load.

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

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

select new spark plugs that correspond to the recommended physical dimensions and heat rating for a specific internal combustion engine;
refuel with high-quality fuel at a proven gas station;
after installing the spark plugs, go on a trip along the highway, which will cover a distance of at least 30 to 300 km;

Only after these steps can you unscrew the spark plugs, after which you can judge the operation of the internal combustion engine based on their color, soot and condition. It should also be taken into account that in the CIS the quality of fuel is significantly inferior to that 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 be reduced by 20-30%.

It is important to understand that although many manufacturers guarantee normal operation of spark plugs 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 to unscrew the spark plugs in parallel with each scheduled maintenance (10 thousand km) to check them, since they may need to be cleaned of carbon deposits, adjusted the gaps, or even prematurely replaced.

Finally, we add that the color of the spark on the spark plug can also partially indicate the presence of problems with the spark plug 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 vary from reddish to white or yellow.

In this case, a more important indicator is not what color the spark on the candle should be, but the discharge power and breakdown depth. At the same time, it is recommended under conditions of high pressure in the combustion chamber. There are special stands for such a test, since there are quite common cases when during a normal test there is a spark, but after screwing it into the engine certain malfunctions occur.

How to check spark plugs and clean them

The trouble-free operation of the engine installation depends on the quality of functioning of the spark-forming elements. Spark plugs need constant checking and timely replacement. Plating on them not only indicates problems, but also significantly deteriorates the quality of the spark.

It is recommended to check spark plugs only when they are “fresh”. They must be run for no less and no more than 150-200 kilometers. Then you will be able to get the most accurate readings.

The check comes down to:

installation of a new set of elements;
running the car for 150-200 km;
dismantling components and checking them visually.

Before undertaking such testing, it is recommended that the Hall sensor be thoroughly tested.

There are several ways to clean spark plugs:

removing scale with a brush and sandpaper;
sandblasting;
ultrasonic treatment;
chemical cleaning.

The mechanical type of cleaning, which involves the use of a wire brush and sandpaper, is the simplest. A car enthusiast can quickly remove plaque. However, there is a risk of damaging the insulator of the sparking part, leaving scratches on it, or breaking the interelectrode gap.

Sandblasting is also considered mechanical. This method is actively used at many service stations that have adopted a compressed air installation. This is an inexpensive and effective way to remove plaque.

Ultrasonic treatment involves the use of chemicals and wave action. However, excessive deposits cannot be removed using this method.

Chemistry is the best cleaning method. You can use vinegar, phosphoric acid, and even Coca-Cola drink.

It is advisable not to let the spark plugs become critical. Taking care of the ignition elements, timely checking and replacing components is the key to a good start and trouble-free operation of the car.

What does a spark plug look like on a working engine?

Typically, its average service life is approximately 30 thousand kilometers. But correctly selected and high-quality candles can work much more. The resource very much depends on what material the manufacturer chose for the manufacture of electrodes. Thus, a spark plug with a bimetallic electrode will be more reliable than a regular one, and its service life will be longer. The multi-electrode product also has a longer service life. Another advantage of such elements is that there is no need to adjust the gap. Spark plugs with electrodes coated with platinum will work stably and for a very long time.

In order for engine diagnostics using spark plugs to be informative and the information itself to be truthful, the engine must be warmed up. But there is a nuance here - you need to drive at least 5 kilometers by car

It is important that the load on the motor is decent. Then the engine is allowed to cool - it is problematic to unscrew hot spark plugs

Also, you should not try to diagnose the engine based on the condition of the spark plugs if the engine warmed up to operating temperatures at idle. In this case the information will be incorrect. The spark plug will be covered with black soot, because the engine was running on an enriched warm-up mixture.

If the engine is fully operational and the spark plugs are correctly selected, then there will be only a small amount of carbon deposits on the electrodes. The color will be coffee to light brown. More often you can see gray candles. Well, and most importantly, there should be no traces of oil on the spark plug and electrodes. If the part looks exactly like this, then the electrode will burn out evenly, and there will be no mechanical damage to the spark plug. Fuel consumption on such an engine will be minimal, and the amount of oil will be as if it had just been filled. The engine starts perfectly.

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

What does the color of 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 when conducting this test:

Checking on a cold engine

. Having unscrewed a spark plug on an engine that has been turned off for a long time, it is not always possible to determine the color correctly, for example, during this time the gasoline dries completely;

To correctly assess the position of the spark plugs, you need to not only warm up the car, but also drive it for about 5 kilometers. In this case, you can accurately assess the performance of this ignition element.

Candle color

. First you need to determine what the candle should look like in normal condition. Firstly, it must be dry. Its color should ideally be light sand. However, it is possible that the electrodes may darken to a coffee color. There should be no oil stains or soot on it. The electrode may burn out slightly. You may not even see this on an iridium spark plug. Any other condition of the candle is a cause for concern.

Outwardly, this looks like partial or complete destruction of the electrode. Partially damaged, sometimes the electrode is on old spark plugs. This is a completely natural phenomenon at the end of a spark plug's life. Another case is complete destruction of the electrode. This happens when the engine is operated under detonation conditions. In this case, it simply collapses due to explosive loads. At best, this happens in small fragments with complete burnout. Sometimes the electrodes fall off immediately and get stuck in the exhaust valve, which leads to the need to repair the cylinder head.

Sooner or later you will have to replace the spark plugs. Unfortunately, when buying them it is easy to run into a fake. Such spark plugs work much worse and also fail faster.

Therefore, when purchasing, you need to pay attention to signs of fakes. It is advisable to visit the manufacturer’s website, where you can find out the signs of the “correct” candles

In the store, be sure to look at the condition of the packaging.

What color of plaque is considered normal?

The normal color of spark plugs for regular vehicle use is light gray or taupe. A thin layer of plaque of this shade does not interfere with the operation of the internal combustion engine.

Traces of erosion, melting or wear of the electrodes are an indication to replace the spare part, regardless of its color and service life.

Red soot

Red carbon deposits are another common type of “spraying”. Usually, such a deposit does not mean that the engine is faulty, but is the effect of special additives. As you know, there are many different additive components in oil and fuel - they give the candle a reddish tone. Although when the ratio of additives is observed and the necessary standards are taken into account, deposits should not appear. The worse the quality of the oil (gasoline), the brighter the soot will be. It can even resemble rust. What kind of additives can create a similar redness effect? If we are talking about oil, then these are detergent additives. Although it is very difficult to make an accurate diagnosis here. When red carbon deposits appear, there is no need to do any diagnostic or repair work on the engine. All you need to do is change the oil, fuel and spark plugs (or just spark plugs).

Spark color

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

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, you can draw conclusions about damage to the module, distributor or armored wires. Such a spark is knocked out at intervals or appears 1-2 times during testing.
A red or yellowish color indicates the presence of additives in the fuel.

Why does carbon deposits form on candles?

A special feature of how spark plugs work is that their lower part is located directly in the combustion chamber. An electric spark is created at the electrodes, these elements of the ignition system experience thermal loads during the combustion of the fuel charge, operate under high pressure conditions, are affected by various chemical processes, etc.

It is quite obvious that under such conditions, over time, deposits inevitably form on the spark plug, carbon deposits appear on the spark plug insulator, etc.

At the same time, it is important to know what kind of carbon deposits should be on the spark plugs if the engine and spark plugs are operating normally. To begin with, in a properly working engine, a gray soot forms on the spark plugs, more like a gray coating, which covers the electrodes with a small and relatively uniform layer

As a rule, most problems are usually associated with the settings of the ignition timing (ignition timing) and the operation of the ignition system itself, the quality of the fuel-air mixture, and temperatures in the combustion chamber. The color of the carbon deposits on the spark plugs allows you to more accurately identify existing deviations and localize the fault.

Main symptoms of malfunctions

At night, a spark breakdown between the spark plugs and the tip may be visible;
Wet or smoked electrodes;
Glaze on electrodes;
Crack on the insulator;
Melting of electrodes.

Indirect signs of a spark plug malfunction include: misfires, engine trouble, increased fuel consumption, unstable starting, and the smell of unused gasoline from the exhaust pipe.

To check the further suitability of a candle, there are several options:

A device that simulates the pressure in the cylinder at the end of the compression stroke;
With a pistol - a probe;
Checking the ignition spark;
Supplying a spark to the spark plug by applying it to ground and applying voltage through the ignition.

Normal gap, what you need to focus on

We have very specific limits. Bottom from 0.4 mm (and everything below), top from 1.3 mm (and everything above). So what is considered the normal size for your car?

You know, there are differences here too, they are connected primarily with the car’s ignition system, which can be roughly divided into three types:

1) For carburetor type, with distributor - normal clearance is from 0.5 to 0.6 mm

2) For carburetor type, with electronic ignition – 0.7 – 0.8 mm

3) Injector – 1 – 1.3 mm

Why such difference? - you ask. The answer is simple - it's a matter of the ignition system and electrical circuit. The carburetor has the lowest voltage, so the spark will be weaker, and therefore the gap should be smaller. But the injector has the strongest energy system, so here the gap is increased, normal is considered to be 1 mm, and on many foreign cars it is 1.1 mm.

Where does red carbon come from on spark plugs?

Many people can see the characteristic red soot on their spark plugs. I was always interested to know the reason for this red color. In Figure 1 you can see the color of an ordinary working candle. And compare it with a photograph of a candle with a red soot formed as a result of work. It seemed like it would be red, so I turned it around and drove on. But not many people realize that, in principle, candles in such a deplorable state can be safely thrown away, no matter how much you regret the money spent.

Therefore, it is worth finding out the reason for such terrible soot. Your spark plugs turn red because gasoline manufacturers add manganese-iron anti-knock additives to the fuel.

Is this normal, you ask? Of course not, because by adding such additives to gasoline, unscrupulous sellers increase the octane number of gasoline. And they sell it as expensive high-octane premium quality gasoline. This practice is typical for 95 and 98 gasoline, which is obtained from 92 gasoline.

Long-term use of scorched gasoline leads to metal deposits on the working surface of the spark plug, as a result of which the tip turns brick-colored. But this is only the tip of the iceberg, since a conductive film (plaque) forms on the spark plug, and as a result, the spark plug’s insulation between the electrodes drops significantly. It is much easier for current to pass through the insulation than to punch a gap on the spark plug. Such candles become absolutely useless.

In other words, the next time you change spark plugs, pay attention to whether there is red carbon on them, and if so, then think about which gas station you should refuel at next time. After surfing the Internet, you can read tips for car enthusiasts about how dead spark plugs can be revived by rinsing in a toilet bowl cleaner, such as Silit Beng

After this procedure, of course, there is no guarantee of a positive result, but it’s worth a try.

After surfing the Internet, you can read advice for car enthusiasts about how dead spark plugs can be revived by rinsing in a toilet bowl cleaner, such as Silit Beng. After carrying out this procedure, of course, there is no guarantee of a positive result, but it’s worth a try.

Weak spark at spark plugs

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

A weak spark on the spark plugs is a malfunction that occurs just as when there is none at all, but it is much more difficult to detect the cause of its occurrence. An ammeter won't even be able to help in this case. The best way to determine a malfunction is to turn off a particular 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 turns out that the spark between the spark plug and the high-voltage wire is weak, turn off the distributor from the ignition circuit and check the quality of the spark between the ground and the high-voltage wire of the ignition coil. 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 broken, they must be replaced.

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

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

To check the safety and reliability of contact and isolation of current-carrying parts of the circle from ground, you need to check the inner circle of the breaker, the condition and gap in its contacts at all cam protrusions. When checking the inner circle of the breaker, determine whether the cam, the bushings of the breaker shaft, the axis and the hole for the axis of the breaker lever have not worked, and that 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 in good condition, you should check the serviceability of the ignition coil. Strong heating of the ignition coil indicates a short circuit in the primary winding. The faulty coil is replaced.

Black carbon deposits on spark plugs: causes, solutions

Mass air flow sensor (MAF). The control unit of the injection engine has a program that adjusts the time that the injectors are open. So, this program specifies the ratio of air to gasoline, that is, the proportion of the combustible mixture. If the mass air flow sensor “does not understand” how much air passes through it or its readings are erroneous, then the control unit opens the injectors for too long a time. This leads to more fuel entering the cylinders, after which black carbon deposits form on the spark plugs.
Leaking injectors. In this case, serious excessive fuel consumption will be immediately noticeable. That is, gasoline enters the cylinders even when the injector is closed. As a rule, all injectors do not fail at once, so not every cylinder will have a black spark plug.
Incorrect carburetor adjustment. This point is relevant for carburetor engines, naturally. This unit is quite complex, therefore, without the proper skills, you should not start adjusting it yourself.

If black carbon deposits on the spark plugs seem to have become stuck and coked, then the reasons for its appearance are more serious:

Engine diagnostics based on carbon deposits on insulators

Take this opportunity to look at the spark plug insulators; their appearance can tell you a lot; you just need to understand what it says. After all, this element of the ignition system works in the combustion chamber of the cylinder and all the processes taking place there are reflected in its condition and appearance. It would not be an exaggeration to say that it is also a diagnostic probe built into the heart of the engine.

The spark plug insulators are in good working order and the engine is running should be light brown in color and should not have soot deposits or burnt oil. If the spark plug insulator and the central electrode are covered with a velvety black coating, then this indicates either a malfunction in the ignition system or incorrect adjustment of the system preparing the fuel-air mixture, and if the engine is fuel-injected, then one of the sensors of this system may fail.
The color of the insulator from light gray to white without carbon deposits indicates an excessively lean mixture.
The brick-red color of the insulator indicates deposits of tetraethyl lead on it and that this spark plug, without cleaning, will soon experience an electrical breakdown of the insulator and failure.
Traces of oil on the spark plug, as you might guess, indicate increased oil consumption. To determine its cause, observe the exhaust immediately after starting the engine. If there is a blue cloud of smoke with the smell of burnt oil, this indicates that while the car was parked, oil has accumulated in the combustion chambers through the valve seals. So it's time to change the caps. If the smoke is all blue from starting the engine and beyond, then the reason for oil consumption is most likely wear on the piston rings.
A thick, white, loose coating on the spark plug appears when antifreeze enters the combustion chamber; this happens when the gasket between the cylinder head and the cylinder block is defective or due to thermal deformation of the cylinder head. When an engine operates with such a malfunction, bubbles of exhaust gases are observed in the expansion tank, passing into the cooling system through the same defect. The exhaust from such a malfunction partly consists of coolant vapors.

Weak spark at spark plugs

The car has been sitting for a long time, now it starts hard, and when the engine warms up to operating temperature, it practically refuses to start.

A weak spark can be detected “by eye”. Unscrew the spark plug, connect it to the wire and touch the engine housing. If the spark is stable and blue, then there is another malfunction. The battery or generator is dead, or perhaps water (condensation) has entered the fuel supply system from being parked for a long time.

Consider the case of contact ignition:

If the spark on the electrodes of the spark plugs is weak or too short-lived, the working mixture in the engine cylinders burns incompletely or does not ignite at all. Most often, it is caused by malfunctions of the spark plugs themselves, as well as burning, wear, or contamination of the breaker contacts. We will consider the most likely causes of malfunctions. Typical ignition COIL malfunctions are: cracks in the bakelite cover, turn-to-turn short circuit in the primary winding and insulation breakdown in the secondary winding. Damage to the ignition coil windings usually occurs due to its overheating, and most often due to the operation of the ignition system for a long time after the engine is turned off. To check the ignition coil, bring the end of the wire removed from the central socket of the cover to the cylinder head at a distance of about 4 mm, turn on the ignition and spread the breaker contacts with your finger. The absence of a spark indicates a damaged spark plug that needs to be replaced. To check the capacitor, you need to disconnect its wire from the ignition distributor housing and connect it to the high voltage wire of the ignition coil. Then turn on the ignition and manually open the breaker contacts several times, and then bring the end of the capacitor wire closer to its body. If no spark occurs, then the capacitor is faulty and should be replaced. Cracks in the distributor cap are easily detected during inspection, and current penetration can usually only be noticed in the dark. A damaged distributor cap or rotor must be replaced. However, if the disruption of the spark discharge is caused by dust or contamination of the insulation, it is enough to wash it with unleaded gasoline and wipe it dry. The metal contacts of the cover and the metal plate of the distributor rotor should be periodically cleaned with a file or an abrasive plate. As a result of damage to the insulation, breaks may occur in the wires or they may short to ground. In this case, the low voltage wires can be repaired, but the high voltage wires must be replaced.

Communities › UAZ drivers › Blog › Doesn’t start (very bad spark)

Good evening! I have a UAZ 31512. I took it recently, I want to make it my own, I haven’t registered it here yet. Today, for no apparent reason, the UAZ suddenly stalled. Attempts to start it up were unsuccessful. I turned out the spark plugs and checked the spark, the spark is very weak and not constant. I changed the spark plugs a week ago for new ones, checked on the old spark plugs and the spark was also very weak and not constant. The distributor cover is new, I don’t know what else could be the reason, I’m not good at electrics. In the end, they dragged me home using a tie.

Where to climb and what to dig in? And most importantly, how much money can this cost?

Comments 40

An electrician came today. The problem was found, the carburetor throws so much fuel that it floods the spark plugs, today I bought new spark plugs, installed them and the UAZ started. Now we need to find a good carburetor specialist.

What kind of ignition? Contact or non-contact?

If only I knew =) How to distinguish contact from non-contact?

I checked the ignition and it's contactless. What is the approximate cost of ignition ATE-2 on UAZ? And is it difficult to replace it?

Today we installed such a system, a distributor on the hall sensor, a 2108 coil and a commutator, set it up with a scrubscope, new armor plates and spark plugs, but bad luck, there is no idle only on the suction, what to do, the carb was adjusted half a year ago, do it again.

After aligning the distributor with the strobe light to the mark, you must also tighten it manually. And yes, how did everything work before the replacement?

I don’t know how to say it, in general, I had an underwater ignition and everything seemed to be humming, but the distributor began to stand out and rattle from it, as a result, on the trip it started grinding again, I took it off and twisted it a little and anointed it, but it stopped smoking, the spark plugs turned black and I decided no longer worry about this ignition and installed this, as I wrote above, today we rehearsed the carb, began to drive and keep it idle, but when you remove the armor from the spark plug, 1.2 stalls and 3 does not react, it’s kind of weak, 4 is also not to say that they were The changes are just a little bit, they did the head but one valve is rattling, in general something like this.

It's not a crime to rattle a valve. A squeezed one is evil, it can burn out. Black spark plugs = too much fuel, lighter has nothing to do with it. The intake manifold gasket needs to be soaked with water. Carb gasket too, by the way. And throttle shafts. And the engine should not shake at all at idle. And if you put your hand to the exhaust, there should be no spitting either at idle or at speed. I would put the lighter on a little later and look at the carb, it looks like it makes some kind of bodyagu instead of a mixture.

howling today I tested the adjusted carb and ignition, I didn’t start it right away in the morning, but I started it, warmed it up and drove off, the engine’s performance is much better, it pulls not bad either, the only thing is that when you press the gas sharply, it seems to stall or choke slightly and again the speed is normal, The car runs not bad, only today I noticed a new problem, the fuel pump was baked and as it turned out it was crooked on the plane, I had to straighten it and remove the rod by knocking out the cotter pin, but it was filled with paraffin or something, and I assembled everything and this rod was not closed with anything, and now Today I went uphill and the car stopped, somehow I came down and opened the hood, I looked and there was no gas in the filter, I started pumping and then I saw the rod came out and apparently it wasn’t pumping, the rod was driven in and sealed with sealant, in general, so far everything is working.

Failure when pressed sharply - the accelerator pump in the carb or twist the lighter. At the same time, the consumption will decrease - the cars don’t move, we press the pedal more, the consumption increases, but there is little sense.

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Technical specifications, advice for motorists on care and maintenance, auto news and car dealership news

This is interesting: Which carburetor is better for the UAZ engine 417

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

No spark at the spark plugs

Before troubleshooting, it is necessary to more specifically determine the culprit for the loss of spark and conduct a visual inspection of the high-voltage wires, ignition coil and distributor. A trivial central armor wire that has slipped off the distributor cover, a loose connector, or an oxidized (fallen off) terminal on the ignition coil will lead to the disappearance of the spark.

Then we remove the central high-voltage wire, insert a working spark plug into its tip and place it on the engine (so that there is contact with ground). While the assistant turns the engine with the starter, you need to visually verify the absence or presence of a spark at the spark plug. A spark has appeared - the spark plugs themselves, the high-voltage wires or the ignition distributor in the distributor are faulty. There was still no spark - problems with the switch, Hall sensor, ignition coil.

Lost spark, reasons for contactless ignition system

The ignition coil has failed.

Checking the ignition coil. The ignition coil is usually checked for winding resistance and insulation resistance using a tester. For oil-filled coils (27.3705) and dry coils (3122.3707), the resistance is slightly different. Read more: “Checking the ignition coil.” In the absence of a special device for testing, we use the method of replacing our coil with another one that is known to be good.

checking the primary winding of the ignition coil

Checked with an oscilloscope. Since not everyone has it, we use the replacement method - instead of our switch we install a known good one. You can very roughly estimate the performance of the switch based on the voltmeter readings after turning on the ignition (see “Checking the switch”).

It is checked with a voltmeter according to a special connection diagram (see “Checking the Hall sensor”). If there is no voltmeter, we use the replacement method.

Hall sensor, check

Open circuit in low voltage circuit.

Using the diagram, we look through the wires included in the ignition system, and if necessary, “ring” to detect a “break.” See "Contactless Ignition System Diagram".

In the contact ignition system, the list of malfunctions leading to the disappearance of the spark is as follows:

The mechanical breaker in the distributor is faulty.

Its contacts have oxidized, collapsed or burned. There is no gap between the breaker contacts.

breaker contacts

The ignition coil is faulty.
"Open" in the low voltage circuit.

Notes and additions

— To quickly find the reason for the disappearance of the spark on the spark plugs, you need to know the principle of operation of both contact and non-contact ignition systems (for more details, see “The principle of operation of the ignition system”). The purpose of the ignition system is to generate high voltage current at the right moment and supply it to the spark plugs. This is accomplished by interrupting the low voltage current in the primary winding circuit of the ignition coil. In a contactless system, the switch interrupts the current based on a signal from the Hall sensor; in a contact system, a mechanical breaker with contacts is driven by a tetrahedron on the distributor shaft.

More articles on the ignition system of VAZ cars

The quality of the spark on the spark plugs is checked in the same way as in the complete absence of a spark, but it is advisable to change the gap between the ground and the high-voltage wire of the spark plug. A spark that reliably breaks a gap of at least 7 mm is considered good. It’s bad when the spark length is shorter or the spark is irregular. A weak or irregular spark on the plugs has similar malfunctions as its absence, but they are less pronounced; therefore, they are much more difficult to find. Even an ammeter cannot help in this search. The best way to find a malfunction is to exclude this or that 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 will indicate a malfunction of the disconnected device.

If after checking it turns out that the spark between the spark plugs and the high-voltage wire is weak, then exclude the distributor from the ignition circuit.

So, in order to find out the reason for the sudden “triple” (“missing”) of the engine, you need to inspect the car engine itself step by step. You need to start inspecting it with the ignition system, which was described in previous articles.

It is worth considering one more point - if you move the spark plug a couple of centimeters away from the engine “ground” and crank the engine with the starter, but there will be no spark or it will “slip”, but very weak, barely noticeable, then we can state the fact that the spark of your engine the car is weak and this may be due to:

— increased resistance of high-voltage wires;

- ignition coil malfunction.

If the spark is normal, you should pay attention to the high-voltage wires. You need to remove them and examine each wire individually. The first step is to inspect the tip of the wire that is inserted into the spark plug. This tip should.

Back Contents Next

Are the spark plugs to blame? Initial check. If there is a spark. A note about electronic ignition. Our “research” equipment. If there is no spark. We continue checking the low voltage circuit. Distributor cap. Distributor runner. One cylinder is not working.

The engine runs intermittently.

As before, we are talking about a situation where the engine did not become capricious in some modes, but stopped working completely.

Are the candles to blame?

In the event of a sudden failure of an engine that previously worked without any problems, this question should be answered in the negative. Of course, any spark plug can fail at any time, but the simultaneous failure of all four spark plugs is less likely than winning a car in the lottery.

There is, however, a completely possible situation. This is when, due to a malfunction of the carburetor, gasoline, as they say, poured into the engine in a stream, then the spark plugs.

Failures in the car’s ignition system, no matter what they are, are always unpleasant because each of them negatively affects the operation of the engine or leads to its complete stop. And very often it happens that a breakdown of the ignition system appears precisely at the moment when it is necessary to use the car. I think this situation has happened to many drivers. So, in order to prevent an emergency malfunction, you need to independently diagnose the car from time to time. I will tell you about a problem that occurs when starting the engine and it sounds like “no spark from the ignition coil.” After reading the article, you will learn what to do when the car does not start and the ignition coil sparks.

Causes

To determine that the problem is in the inductor, you can observe the behavior of the car. If the ignition coil sparks, the car behaves as follows:

The intensity of the engine sharply decreases; They're starting.

The vehicle's power plant does not start. Unfortunately, this situation is familiar to the vast majority of domestic motorists. And the reasons, and, consequently, the solution to this problem lie in the performance of your car’s ignition system, or rather, in the serviceability of its individual elements. In particular, ignition coils. So, in this article we will look at malfunctions of the ignition coil, in which starting the car engine is difficult or even impossible, as well as an algorithm for checking its (coil) performance.

This is interesting: Driving a car at night, 5 mistakes

Signs of a faulty ignition coil

The ignition coil of a modern car is, in fact, a unified current converter.

The low voltage current coming from the battery is converted into high voltage current using this device and then supplied to the spark plugs. Based on the functional purpose of this element, we formulate the main signs indicating.

Malfunctions of the car’s ignition system are unpleasant because any of them is always accompanied by serious interruptions in the engine’s operation or its complete stop. The main sign of a malfunctioning ignition system is the complete absence or “weak” spark between the electrodes of the spark plugs. What to do if there is no spark, and where to look for it? Read about this and more in our material.

Most often, the spark disappears precisely at the moment when you need to go somewhere. In order not to push the car to the nearest car service center, it is important to understand what the operation of the ignition system depends on, then finding the missing spark will not cause any particular difficulties.

At the end of this article, watch the video instructions for finding a spark in the ignition system of VAZ cars.

And below we propose to get acquainted with the algorithm for searching for a missing spark in a car’s ignition system.

Why is there no spark at the spark plugs?

Reasons for the lack of spark on the candles.

GAZ cars

A reliable indicator of the health of the ignition system is the color of the spark that jumps between any of the spark plug wires and ground or between the high voltage wire of the ignition coil and ground, as well as the size of the gap overcome by the spark. The color and size of the spark gap can be observed in a dark place or in low light by rotating the engine crankshaft with the starter or using the crank.

With a working ignition system, the spark is white with a blue tint and is able to overcome the spark gap between the wire and ground, equal to 6-7 mm, without interruption.

If the spark is purple or almost colorless, this indicates damage to the secondary circuit of the ignition coil, distributor cap, or high voltage wire. Such igkra overcomes the gap of 6-7 mm intermittently or cannot overcome it at all.

The spark does not overcome the yellowish-red color.

A situation in which the engine does not start the first time, or does not start at all, can hardly be called pleasant. Experienced motorists know that any malfunction of the ignition system leads to partial, and often even complete failure of the car engine. So, if your car does not start, the reasons are:

no current signals are supplied to the ignition coil; fuel does not reach the carburetor; current from the ignition coil does not enter the distributor; reason there is no spark from the ignition coil; no spark passes between the electrodes of the spark plug; fuel liquid does not enter the combustion chamber; The ignition distributor is broken.

The engine can also be blocked by the starter. But before checking the starter, inspect the condition of the electric motor winding; if it is not damaged, then the starter is most likely in good condition. Pay attention to the ignition coil.

The ignition coil is a converter of low voltage current to high voltage current in the vehicle ignition system.

Everything is considered for the classic contact ignition system (B117 coil) and a distributor with a contact group. Prologue: the search for a spark can only begin after making sure that gasoline is entering the carb, the starter is turning vigorously, but the engine does not start and there are not even any flashes.

Introductory: contact “+B” on the coil (the middle or common point of the windings) is what comes from the battery (more precisely “+”) - The ground from the distributor comes to “7” (or nameless contact), in the case of closed contacts in distributor (then current flows through it). the secondary winding is connected by a high-voltage wire to the distributor cover. Without going into too much detail, the coil operates on the principle of a transformer. When current passes through the primary winding, a magnetic field is created in it. When the circuit of the primary winding is opened by the distributor, the magnetic field disappears, while a high voltage current is induced in the secondary winding (there are many more turns in it than in the primary) - up to.

Troubles associated with interruptions in the car’s ignition system are often associated with serious problems in the engine’s operation and the inability to start it. How to understand why the spark between the electrodes of the spark plugs is weak or for what reason there is none? Any driver should know the answers to these questions, since problems in the ignition system can appear at any time and take you by surprise. At the same time, you can be present in places from which the service station is tens of kilometers away. Then you will have to personally solve the problems that have arisen. In this article we will help answer the question: “Why did the spark disappear in the ignition system and how to fix it?” so that you can easily cope with this trouble.

Troubleshooting

To find out why there is no spark, you must first inspect the wires and blocks of the ignition system. If there are traces of oil, water or dirt, wipe them clean with a dry cloth. Then you try.

VAZ 2112 spark plugs are filled, gasoline is on the electrodes and threads

The VAZ 2112 spark plugs flood and the engine does not start, a very unpleasant phenomenon that happens more often during cold weather. The disease is common, taking a lot of nerves and time from car owners. This simple instruction will tell you how to overcome such a disease, let's start with the reasons.

Causes

As always, there are several reasons for this phenomenon, now we will deal with them, as well as with ways to eliminate them. When the spark plugs are filled with gasoline (they look like in the photo above), it doesn’t really matter whether you have a carburetor or an injector. This happens regardless of the type of fuel system installed on the car:

A special feature is that the spark plugs are filled with gasoline much less often in warm weather; this often happens at subzero temperatures. First, let's try to figure everything out in order: why the VAZ 2112 spark plugs were flooded, what needs to be done in such a situation to start the engine, when.

It is written on the Internet that you don’t need to solder anything in them and everything works like this... In practice, these switches performed poorly - there was no spark on them at all, and a friend’s nine started with half a kick on them, so with GREAT DIFFICULTY I found the Astro switches »

I also bought 5 meters of single-core 0.75 wire for signal circuits and the same amount of 1.0 wire for the power circuits of the structure. Wiring kit for BSZ VAZ 2108, Kalina ignition coil chip. To connect the system to the wiring of the computer, I used male-female wires from the lambda probe.

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White carbon deposits on the ignition system elements

The gradation of electrode colors from light gray to white (light yellow is also possible) is evidence that the engine is running on a lean mixture. Related reasons may be:

The product is too hot. The heat rating of the product is lower than that recommended by the manufacturer.
Large ignition timing angle.
Using low octane gasoline.

When analyzing the factors that caused a poor quality mixture, it is useful to check for the presence of abnormal glow ignition. A symptom indicating its presence is the reluctance of the engine to stall when the ignition is turned off. In total, this means that the “match” was not created for this engine. This conclusion will not be spontaneous if the heat removal from the igniter is not impaired due to loose tightening of the threaded connection, and there is no dirt under the sealing gasket. If this is the case, then you will have to buy a new kit, after consulting the instruction manual.

Brick candle

Spark test

Common mistake

What color should the spark be when using a spark tester?

The main symptoms of engine malfunctions that affect the condition of the spark plugs

Candles

Types of soot

Light electrodes

Black soot

see also

Pouring candles when cold

Replacing spark plugs on a Z18XE engine

Lubricant for injectors and spark plug threads

Spark plug and coil lubricant

How to check spark plugs

Extreme conditions of spark plugs

Metal dust, oil, gasoline

Destruction of the central electrode with a ceramic insulator

Ceramic skirt failure and erosion

The spark plug is filled with gasoline

The main reason for the raid

Deviations from the norm: types of unhealthy carbon deposits on the “injector” spark plugs

Oil on candle thread

Whitish soot

Red-brown coating

Different colors of spark plugs: what does it indicate?

How to check spark plugs and clean them

What does a spark plug look like on a working engine?

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

What color of plaque is considered normal?

Red soot

Spark color

Why does carbon deposits form on candles?

Main symptoms of malfunctions

Normal gap, what you need to focus on

Where does red carbon come from on spark plugs?

Weak spark at spark plugs

Black carbon deposits on spark plugs: causes, solutions

Engine diagnostics based on carbon deposits on insulators

Weak spark at spark plugs

Communities › UAZ drivers › Blog › Doesn’t start (very bad spark)

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World of cars

Technical specifications, advice for motorists on care and maintenance, auto news and car dealership news

No spark at the spark plugs

Are the candles to blame?

Causes

Signs of a faulty ignition coil

Why is there no spark at the spark plugs?

GAZ cars

Troubleshooting

Causes

White carbon deposits on the ignition system elements