Engine diagnostics based on the condition of spark plugs

It is difficult to find a car owner who has not heard about spark plugs installed in a vehicle. First of all, it is worth saying that when you first get acquainted with such car components, it may seem that they have a very simple design made of ceramic or metal materials. Moreover, in fact, they play a fairly important role in the functioning of the vehicle engine. You can tell a lot by the appearance of a part, including about the functioning of the engine, as well as its individual technical components. The condition of the spark plugs by their appearance allows you to determine what problems there are in the car’s operation and, accordingly, eliminate them. Let's try to figure out how to determine the condition of the engine by spark plugs.

The principle of operation of components of this type

Today, there are several types of components of this type that are installed in cars. Here we are talking about both photos of parts and the operation of spark plugs. So, here are the components:

1. Spark type.
2. Arc type.
3. Catalytic type.
4. Incandescent.

A person who has virtually no knowledge of this issue most often thinks about the issue of identifying spark plugs. First of all, it should be noted that in cars with a gasoline engine, the first types of spark plugs are used. In this case, the mixture is ignited by means of an electric discharge, which occurs using an electrode. The discharge voltage process can be measured in Volts. The indicator can be up to several thousand volts. The functioning of components is a streamlined process, since they begin to function the moment the car engine starts running.

A fairly large number of car owners mistakenly assume that if the engine diagnostic photo shows the spark plugs are in decent condition, then most likely there are no difficulties in the functioning of the engine. Even in the cold season, they will not need to be changed. Moreover, this statement is true only if the technical condition of the parts (candles) is good. To understand the condition of the component, you need to determine what the spark plug should look like. If you have this knowledge, then by looking at the appearance of the spark plugs, you will be able to determine exactly what condition they are in.

The working part is covered with black soot

Black spark plugs are a symptom indicating that the fuel mixture is too rich (the proportion of gasoline is increased above normal). Therefore, the fuel does not burn completely and forms a layer of soot on the chamber walls and spark plug electrodes.

An additional sign of this problem is black or dark gray smoke from the exhaust. When over-gassing, small flakes of soot may fly out of the pipe.

There are quite a few reasons for the enrichment of the air-fuel mixture, the most common ones look like this:

1. One of the key sensors has become unusable - air flow, temperature, throttle position or oxygen content in the exhaust (lambda probe). The controller activates the emergency program and prepares the mixture according to other indications.
2. Carburetor malfunctions (clogged air jets, worn throttle valves, etc.).
3. Failure of the pressure regulator in the fuel line.
4. Wear of nozzles - nozzles “overflow” and leak when the power unit is not working.
5. Problems with sparking - the power of the electrical pulse is not enough to ignite the combustible mixture normally.

Important! If during the diagnostic process you find black spark plugs, the fault should be found immediately. Increased gasoline consumption is only part of the consequences of excessive enrichment.

There are others, not so harmless:

• some of the unburned fuel penetrates the crankcase and dilutes the oil, accelerating the wear of engine parts;
• the other part gets into the exhaust manifold, which is why shots are periodically heard in it;
• soot clogs the expensive catalytic converter - it has to be cleaned or replaced with a new one;
• The service life of the spark plugs is sharply reduced.

When running on a rich fuel mixture, the engine “chokes”, unstable idling and skipped cycles are observed. When a certain amount of soot heated to a high temperature accumulates in the chambers, a “pseudo-diesel” effect occurs - after turning off the ignition, the engine does not want to stall and makes 2-10 crankshaft revolutions. The reason is hot soot, igniting the combustible mixture without a spark.

The nuances of performing engine diagnostics based on the condition of the spark plug

Experts who work in the field of vehicle diagnostics and repair recommend performing visual inspections at certain intervals. The fact is that by the appearance of this component it is possible to determine what condition the motor is in and, as a result, carry out repair work in a timely manner. If you neglect this procedure, a situation may occur when the engine stops working, and the repair process will be very expensive. Quite often, to determine the technical condition of a vehicle, it is necessary to look at the presence of carbon deposits on the surface of the part. The presence of carbon deposits, as well as the color of the part, allows you to determine whether the spark plugs are working or not.

By studying the photo and description of carbon deposits on spark plugs, you can learn about most of the problems that exist in the car. If, after driving three hundred kilometers, the component that supplies the spark is brown, then you don’t have to worry about the fact that there is any malfunction. In this matter, we can safely say that the technical condition of the engine is in good working order. If there is black carbon deposits on the surface of the part, this indicates a blockage has occurred. Here we are talking about contamination of the car air filter. Depending on the color, you can draw conclusions about the functioning of the engine.

In some situations, the color of the part is white or gray . If, when performing diagnostics based on the color of the spark plug, it was revealed that the components have a light shade, then we can conclude that there are problems associated with the mixture of fuel used. Here we are talking about the fact that the exhaust valves have failed, and there is also quite strong overheating in the combustion chamber. That is why it is impossible to delay repair work. Experts recommend contacting a service station almost immediately. If the color is red , then this indicates quite large iron impurities present in the fuel liquid. As a result, they will cease to function completely. To carry out repair work, you will need to clean the motor. In some cases, replacing the oil fluid with a new one may help. In this case, this procedure should be performed two to three times.

Condition of spark plugs by appearance

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.

There is no point in delaying in finding out the circumstances that caused this soot-colored condition on the new spark plug.
A lean mixture directly causes overheating of both the igniter and the combustion chamber. Ultimately, this situation can lead to burnout of the exhaust valves. 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.

Other ways to determine engine condition using spark plugs

There are other ways to determine the condition of a spark plug. In this case we are talking about the problems that exist in the malfunction of oil deflector type caps . As a result, there is a fairly large waste of oil fluid. A characteristic sign is traces of oil on the threads of the candles.

These include the occurrence of “triple” of the engine, a very long process of starting it, as well as exhausts that have a white-blue color. In addition, existing traces of oil fluid and unburned fuel may indicate a problem associated with the destruction of the valve, as well as the partition that separates the piston rings. Note that in this case there is a fairly high consumption of fuel fluid. Most often, it increases several times.

If the process of engine detonation occurs regularly for a long time, a situation may arise when the electrode breaks down. Thus, this parameter also needs to be monitored. As you can see, with the right approach to this issue, the process of identifying faults existing in the engine compartment becomes completely uncomplicated. Every person should remember that if problems are identified in time, then in the future there will be no situation when the car’s engine completely fails, and its repair will be expensive.

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.

Why is the fuel mixture supplied lean?

• 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.

Note. Often the light shade of the working electrodes is explained by the type of fuel used. If the car is operated on methane or liquefied gas (propane-butane mixture), this color is considered normal.

How to diagnose spark plugs using photos

By studying photos of spark plugs, it is possible to perform diagnostics. Inspection of a component should be performed after it has been in operation for an extended period of time. Ideally, the inspection will be carried out after the vehicle has been driving on a country highway for a long time.

One of the problems for car owners is when they make a mistake when performing diagnostic work on their own. Here we are talking about a situation when, after starting the engine at a negative temperature, the spark plugs are initially unscrewed, and then it is determined that they are black. You can guess that the person is drawing a conclusion about the wear of the component. In fact, black carbon deposits can appear during engine operation during a “cold” start. Thus, experts recommend drawing any conclusions only after the vehicle has driven at least 150 kilometers. It's even better if the distance is large.

Spark plug

Condition of the candles

So, let's try to figure out how to determine the condition of the engine from photos of spark plugs. If this component is in fully working condition, the appearance of the electrode will be brown . In turn, the presence of soot will be practically absent. There will also be no oil marks. People whose car has a similar engine can be confident in its technical condition. Most likely, the car will have minimal fuel consumption. You can also determine by color that the car has increased fuel consumption. The color of the candle will be black. The cause of deposits on the electrode can be an air-fuel mixture, as well as a clogged air filter.

If the color is light, then on the contrary, the mixture is very poor. In such a situation, there is reason to worry. Heavy loads become one of the reasons for engine overheating. In addition, the component itself can also overheat greatly.

If the component is red, this indicates that the vehicle has been running on gasoline for a long time, with a large number of additives contained in the metal. If you operate a car on such fuel for a long time, this leads to metal deposits and insulation of conductive deposits. In addition, there is a possibility that other components included in the motor’s design will fail.

Traces of oil

Often, when studying photos of working spark plugs, you can see that they have traces of oil fluid . A special concentration of such traces is located on the threads. A motor with such spark plugs, after a long period of inactivity, most often begins to “triple”. The main reason is the poor quality of the oil deflector type caps.

It is impossible not to talk about what a working spark plug looks like when it was removed from a cylinder that has stopped functioning. The electrode and skirt are covered with a very dense layer of oil fluid, which is mixed with drops of fuel fluid and small particles that are destroyed. The main reason for all this is the process of destruction of the valves, as well as a breakdown that occurs in the partition between the piston rings, as well as the seat. The car engine also begins to “trouble.” Moreover, this process occurs on a regular basis, which during vehicle operation contributes to the loss of power characteristics of the car, increased fuel consumption and, as a result, complete engine failure.

Spark plug condition

Damage to spark plugs

By diagnosing spark plugs by appearance, you can see when a complete destruction of a component whose structure is made of ceramic occurs. One of the reasons for the situation when destruction occurs is the long-term operation of the engine, the use of low-quality fuel, as well as manufacturing defects. The engine behaves exactly the same as in the situation described above. A good outcome of this situation is when the cylinder blocks remain intact. Otherwise, the repair will not be the cheapest.

There are also situations when ash deposits are present on the removed component. In this case, color does not play any important role. The fact is that the shade of the component can only speak about the functioning of the fuel system. The reason for this situation is the combustion of the oil fluid after the piston rings have worn out or become stuck. Such motors have increased oil consumption and also emit an unpleasant odor during operation.

It should be noted that problems of this type are quite common when operating vehicles. If you do not want the situation to worsen, it is recommended to regularly diagnose your car. Most often, experts recommend performing the engine diagnostic process after the car has driven 30 thousand kilometers. Let us note that it is also important to contact automobile workshops that employ specialists with extensive experience. They know how to determine the engine's operation by the spark plugs and, accordingly, will be able to ensure trouble-free operation of your vehicle. Approach this issue responsibly; no difficulties or problems will arise in the operation of the car.

The condition of the spark plugs by their appearance allows you to determine what problems there are in the car’s operation and, accordingly, eliminate them.

What color is considered normal?

The performance of the gasoline power unit is indicated by spark plug electrodes painted in a light brown tint, without oil deposits and soot. A similar picture is observed in completely new engines and engines that have undergone a major overhaul.

If the color of the working part differs from the specified one, it is advisable to carry out further diagnostics and identify the cause of the problem. Moreover, the engine itself is not always the culprit. What color options are there for spark electrodes:

• light gray or white;
• black;
• brick or frankly red tint.

In addition to all sorts of colors, the candle skirt is covered with various deposits - soot, brown soot, or may simply look wet. These phenomena are also considered signs of various malfunctions. It is proposed to consider each situation in more detail.

About selection

To ensure that the part does not accidentally collapse inside the motor, it is necessary to select the correct kits. For middle and low class cars, the following scheme is used. The simplest and inexpensive candles are purchased, but the manufacturer is known.

This is a valid approach. Although inexpensive spark plugs are designed for only 30 thousand kilometers, or even less, these sets are regularly replaced with new ones along with the replacement of filters and oils.

A new spark plug, even if it is simple, will work much better than an expensive product with a mileage of 60 thousand kilometers. Another argument in favor of installing new inexpensive parts is the quality of domestic fuel. Gasoline uses a huge number of different additives, which significantly reduce the life of the spark plug.

Origin of red plaque

This phenomenon is less common than the effects described above. Why are there red electrodes on some spark plugs?

• the tank is filled with low quality gasoline with additives that increase the octane number;
• a car enthusiast or a fuel supplier adds additives to gasoline, which contain a large amount of metals;
• the owner of the car installed spark plugs in the cylinders that did not match the heat rating.

The reasons for the reddish tint of spark plugs do not pose a direct threat to the power unit, but are harmful in the long term.
Driving on low-quality gasoline with unknown additives a priori accelerates the wear of parts and components. Plus an increase in consumption arising from worsening combustion conditions of the mixture in the cylinders. Operating a car with spark plugs that are “cooler” or “hotter” in terms of heat rating reduces engine power and significantly shortens the life of the elements. A characteristic sign of incorrectly selected spark plugs is a drop in crankshaft speed at idle and missed ignition cycles.