Soot on spark plugs: why is it formed, the state of candles by the color of soot
Content
Special attention deserves the situation when black soot appears on the thread in winter. The influence of low temperatures contributes to the active processing of fuel. If the problem goes away when you start the car in a warm garage, then the engine is good.
Glow plugs are involved in the process of ignition of the fuel-air mixture. In fact, these are spark gaps with a built-in electrode. Temperature fluctuations or errors within the engine cause spark plug deposits to form at an increased rate. On the one hand, plaque indicates the course of a chemical reaction. On the other hand, a thick layer of soot of a strange shade indicates a malfunction inside the system.
What does soot on spark plugs mean?
The glow plug consists of several elements. Each performs a specific function. During operation, the body is exposed to the fuel-air liquid, which leads to the formation of plaque on the thread of the candle.
How to clean spark plugs
Contrary to the delusion of inexperienced drivers, even a new set of fuses will not be clean. Even the correct, infallible operation of all elements will give a residue - a product of the combustion of the mixture.
Why soot forms
A precipitate forms and settles on the candle after the chemical reaction caused by combustion inside the chamber has passed. The normal variant is a brownish, light shade. If the plaque turns red, black, white, then this will only say that urgent repairs are required.
The reasons for the formation of carbon deposits
Dense soot on spark plugs is formed for several reasons:
- fuel fluid does not meet the requirements;
- violated the rules for the operation of parts;
- inside the chamber during combustion, sharp jumps in temperature are recorded.
Reading the color and texture of the precipitate formed is considered by many car owners to be the best way to visually diagnose.
What color should spark plugs be on an injection engine
The new fuse strikes a blue spark. But as it wears, it changes shade: from faint blue to bright yellow.
If the gasoline engine does not fail, the surface of the electrodes will turn light brown. There will be no soot or soot on the surface. The appearance of other shades indicates the presence of malfunctions.
Spark Plug Diagnostics
By staining soot and its structure, experienced car owners determine the nature of violations and plan further actions. It is possible to correctly assess the appearance of the fuse only if the rules are followed:
- Inspection of a new ignition element was carried out after a car run of 150-200 thousand km.
- During the test, an adjustment for climatic conditions was taken into account: at negative temperatures, candles can be covered with a coal-black coating due to excessive saturation of the working mixture, which does not affect the general condition of the engine.
When diagnosing a fuse, keep in mind that the candles self-clean only under the condition of a high engine speed, as well as at a fixed high temperature.
The condition of the candles by the color of soot
If all elements of the engine work correctly, then the glow plugs will be suitable for 30000 km. This is the minimum. Determination of violations by the shade of soot helps to troubleshoot in time and extend the performance of the electrode.
Black
It is easy to see a black deposit on the surface, but it is much more difficult to determine the malfunction:
- Black shade with pronounced oily particles deposited on the thread. If the appearance of blue smoke from the exhaust pipe during the start is added to the described symptom, then the reason is excessive oil entering the internal combustion chamber. This often leads to wear of parts belonging to the category of cylinder-piston type.
- Black shade with soot particles. The formation of such soot indicates low compression. If your engine is an injection type, then this condition of the candle means that the fuel pressure regulator is failing.
Special attention deserves the situation when black soot appears on the thread in winter. The influence of low temperatures contributes to the active processing of fuel. If the problem goes away when you start the car in a warm garage, then the engine is good.
Red
It is easier to determine the cause of the appearance of red soot. This color appears when drivers use fuel and oil additives. A reddish tint is given by additives with manganese or lead. They settle on the surface of the candle, creating a dense layer of soot. To solve this problem, simply change the oil or gasoline.
White soot
A whitish precipitate accompanies accompanying signs: smoke emission from the exhaust pipe or the appearance of an extraneous odor. In this case, the reason lies in the use of poor fuel.
Malfunctioning spark plugs
This concept is used when the mixture contains an excessive amount of air. The cause of depletion is the leakage of foreign air or problems with the air meter.
Glossy white
A shiny or glossy whitish precipitate forms on the surface of the contact electrodes. This is a sign of overheating of the candles. The risk factor is the use of low-quality fuel or problems inside the cooling system. The reasons must be quickly eliminated, but after that it is better to change the candle kit.
Subtle white
A whitish coating occurs when antifreeze enters the engine cylinder. At the same time, white smoke with a pronounced smell comes out of the exhaust pipe. The situation requires elimination of depressurization and replacement of the spark plug kit.
Ash plaque
A sediment that looks like ash or dense soot is a sign of insufficiently stable operation of the injector or carburetor. In this case, the candles are removed, cleaned, put back. Or they change. After the car again passes 150 thousand km after repair, the candles are unscrewed, inspected, and the condition is assessed.
Yellow soot
When a yellow coating forms on the rims or threads, this indicates the use of low-quality fuel. Usually lead is present in the composition, which gives such a shade. The appearance of a yellowish coating is not a reason for urgent repair or diagnostics, but it is recommended to change the gas station. It is better to use fuel that does not contain aggressive additives.
Green soot
The appearance of a green tint is evidence of erosion processes. The reason for this phenomenon is also the use of fuel with additives.
Spark plug diagnostics
The green color is given by the addition of metal deposited on all surfaces. Choosing a different fuel and changing the set of candles will help solve the problem.
Velvet soot
Many car owners call a black coating with soot "velvety". Its formation is a sign of high enrichment of the fuel-air mixture. A similar phenomenon always indicates an excessive consumption of gasoline.
If the engine is injection, then the reasons for overspending can be different:
- loss of sensitivity of oxygen sensors;
- damper failure;
- filter clogging.
To fix the problem, you will need to adjust the fuel supply system to the engine.
Gray soot
The appearance of a grayish tint indicates the use of poor fuel for refueling. The solution to the problem is cleaning the candles from soot and changing gasoline.
The consequences of the formation of soot on candles
After finding out the cause of the raid, it will be necessary to replace the candle sets or repair some parts. Candles, if they are not completely worn out, are sandblasted and reused on the same engine.
The only way to avoid problems is to regularly diagnose the ignition system. As well as proper maintenance and timely replacement of spark plugs.
Ignoring the signals that the car gives leads to disappointing consequences:
- you may not start the engine;
- auxiliary elements of the system will wear out faster - repairs will be required;
- the catalytic converter will fail.
Soot on the NW is a variant of the norm if the shade of the sediment is light brown. When the color of the candles turns red, black or glossy white, this is a signal that there is a malfunction inside the ignition system.
