Many motorists face a situation when the engine begins to work unstable, fuel consumption increases sharply, and thrust falls. In 80% of cases, the culprit of these problems are elements of the ignition system. Ignition plugs - is an expendable material, but their resource can vary from 15 thousand to 100 thousand kilometers depending on many factors.
If you notice that new parts last no more than a couple of months, this is a signal of serious malfunctions in the engine or control system. iridium Platinum models, which must travel 60-90,000 kilometers according to the passport, can "die" for 5,000 if improperly operated. Understanding the causes of premature death of these components will help you save significant money on repairs and frequent replacements.
In this article, we will discuss in detail the mechanical, chemical and electrical factors that destroy spark formation. You will learn to read the engine’s handwriting by the color of the soda and understand why saving on fuel or oil sometimes leads to expensive overhauls. The critical factor in reducing the service life in 9 out of 10 cases is not the quality of the candle itself, but the violation of the engine operating modes.
Impact of fuel quality and additives on resource
The first thing that comes to mind when looking for a cause of breakdown is bad fuel. And this is really one of the main reasons why spark plugs quickly fail. Low octane gasoline or high-sulphur diesel disrupts the combustion process of the fuel-air mixture. DetonationThe slurry produced by the use of the wrong fuel creates a shock wave that physically destroys the electrodes.
Of particular danger are ferrocene additives, which unscrupulous manufacturers can add to gasoline to increase the octane number. When burned, they form a conductive plaque of red-brown color on the insulator. This plaque creates a path for current leakage, and the spark skips not between the electrodes, but on the surface of a ceramic skirt. As a result, sparking It stops and the candle stops working.
In addition, heavy fractions in poor-quality fuel do not have time to burn completely. They settle on the working part in the form of black oily sodium. This layer acts as a thermal insulator, interfering with the normal removal of heat from the central electrode. Thermal conditions It is broken, which leads to either fouling, or, conversely, to overheating and melting.
⚠️ Attention: Do not use fuel system cleaners in the eye. Concentrated additives can wash away deposits from the tank and nozzles, which then clog the filter and lead to impoverishment of the mixture, causing candles to overheat.
Owners of direct fuel injection vehicles (GDI, TFSI, EcoBoost) face this problem more often due to the high sensitivity of the system to the quality of gasoline. Even a short-term refueling at a questionable gas station can leave a trail that will have to burn hundreds of kilometers along the highway.
Problems with the lubrication system and oil carbon monoxide
The second most common cause is the entry of motor oil into the combustion chamber. This can occur due to wear of oil caps, occurrence of piston rings or wear of the valves guiding the bushes. The oil, burning with fuel, forms a dense, black, glossy soda. Oily scoop It has excellent electrical conductivity, which leads to breakdowns of high voltage.
Visually, such a candle looks greasy and black. If you twisted out the part and saw just such a plaque, the problem is not in it itself, but in the state of the cylinder-piston group. Ignoring this symptom will not only lead to constant replacements of candles, but also to failure. catalytic converterwhich will be clogged with the products of burning oil.
It is also worth mentioning the wrong selection of oil viscosity. Too liquid oil penetrates through the gaps into the combustion chamber more easily, especially on a warmed engine. Conversely, too thick oil may not have time to be removed from the piston group, creating conditions for coking. Regular check of oil level and its condition is a mandatory procedure for prevention.
There is a common misconception that synthetic oils are always better. However, in older engines with high mileage, the use of oils with low viscosity (for example, 0W-20 instead of 5W-40) can provoke a panic and, as a result, a quick failure of the ignition elements.
Incorrect selection of the kalyl number and thermal regime
Each spark plug has a parameter called a potassium. It characterizes the ability of the part to remove heat from the working part. If you install a "cold" candle (with a high potassium number) in an engine that requires "hot", it will not have time to self-clean. The nagar will build up faster than it burns, which will cause ignition misses.
The reverse situation is even more dangerous. Installation of a "hot" candle (with a low potassium number) in a forced or turbocharged engine will lead to its overheating. The temperature of the central electrode will rise above 900 degrees Celsius. At this point, the candle itself becomes a source of ignition (potassium ignition), which causes knock-off And it can melt the piston.
The table below shows the main signs of violation of the thermal regime:
| Sign. | Reason. | Consequence |
|---|---|---|
| white or light grey insulator | Overheating, poor mix | Electrode failure, valve failure |
| Black velvety garnet | Underheated, rich mix | Breakdown, three-engine. |
| Melted central electrode | Critical overheating | Total failure, risk of CZ |
| Red raid on the detention facility | Fuel additives | Current leak, unstable spark |
Replace standard candles with analogues with a different thermal range without reconfiguration of the engine is absolutely impossible. This is a direct way to reduce the life of the engine.
Electrical overload and coil failures
Modern ignition systems operate at voltages up to 40,000 volts and above. If ignition or the ignition module is faulty, they can give an unstable impulse or, conversely, too powerful voltage. A breakdown inside the coil often results in the candle receiving a shock dose of energy that destroys the interelectrode gap.
One of the common reasons is the increased gap between the electrodes. Over time, the spark "eats" the metal, and the distance increases. A higher voltage is required to break through the increased gap. CoilWorking at the limit of its capabilities, overheats and fails, often "killing" behind him and a fresh candle.
It is also worth checking the high-voltage wires (if you have them in your design). Cracks in the insulation lead to a leakage of current to the mass ("to the body"). The candle in this case does not receive energy, works half-heartedly, overgrown with soot and ceases to ignite the mixture. Visual inspection in the dark sometimes allows you to see the "dancing sparks" under the hood.
How to check the gap without a probe?
The exact gap can be checked only with a special flat probe. The use of round probes or “by eye” is unacceptable, since the shape of the side electrode can be curved, and the actual path of the spark will differ from the visual distance.
Frequent attempts to start the engine when it is filled with fuel ("overflow"), also create extreme stress. The fuel on the electrodes works as an insulator, and the ignition system tries to break through this barrier, generating maximum voltage. This can lead to a breakdown of the ceramic insulator inside the candle case.
Mechanical damage and installation errors
The human factor is no less significant cause of breakdowns. When screwing a candle, it is important to observe the moment of tightening. The insufficient moment will lead to a violation of the heat sink (the candle is not tightly pressed to the head of the block) and possible twisting. Excessive moment can cause deformation of the body, damage to the thread in the block head or even a split. ceramic.
A crack in the insulator, even microscopic, opens the way to hot gases inside the candle. This causes instantaneous overheating of the central electrode and its burnout. Often such cracks occur when sloppy handling of the tool or the fall of a candle on a hard surface.
Another mistake is the use of candles with an inappropriate length of the threaded part. If the thread is too long, it can rest on the piston or valve at the upper dead point. The consequences of such a collision are catastrophic: from flexing the valves to the destruction of the piston group. If the thread is too short, the stain accumulates in the cavity of the block head, which can then get into the cylinder.
☑️ Checking before candles are placed
Always use a dynamometer key when installing. It is impossible to determine the exact moment with the hand "to touch", especially if the thread in the head of the block already has production or contamination.
Impact of driving style and engine modes
The style of operation of the car directly affects the state of the engine. Frequent trips over short distances, when the engine does not have time to reach the operating temperature, contribute to the formation of condensation and incomplete combustion of fuel. In such circumstances candle do not reach the self-purification temperature (about 400-500 ° C) and quickly overgrown with soda.
Aggressive driving with constant acceleration to the floor also does not pass without a trace. The engine runs on enriched blends for cooling, which leads to coking. In addition, constant high loads require perfect spark formation, and the slightest defect of the candle leads to the passage of ignition under load, which is destructive to pistons.
The optimal mode for longevity (durability) of parts is a mixed cycle with regular trips along the track. Long movement at a constant speed allows you to warm up all the nodes and burn out excess deposits. If your car is used mainly in the city ("repairer"), you will have to change the candles more often than the regulations.
Once every 2-3 thousand kilometers it is useful to give the engine a load: accelerate in transmission below the usual to 4000-5000 revolutions and drive so 10-15 seconds. This will help burn the scorch with pistons and candles.
⚠️ Attention: Don't ignore the three-engine. The operation of the engine on 3 cylinders (for 4-cylinder engine) leads to the fact that unburned fuel washes the oil film from the walls of the cylinder, causing accelerated wear of the CNG and the occurrence of rings.
Diagnosis of the state by appearance
The twisted candle is the best diagnostic tool that tells about the health of the engine. The normal color of the insulator is shades of light brown, coffee or gray. This indicates the correct ratio of fuel and air, as well as the serviceability of the ignition system.
If you see white, almost porcelain color with interspersed melted metal - the engine overheats. Possible causes: poor mixture, malfunction of the cooling system or too late ignition. Black, dry, soot plaque indicates a rich mixture, problems with the air filter or sensors (lambda probe, DMRC).
The oily black plaque mentioned earlier requires immediate intervention in the engine compartment. And the presence of whitish deposits on the electrodes or metal erosion indicates that the resource of the part is exhausted or the working conditions are extreme. Regular visual inspection (at least once in 15-20 thousand). km) will allow problems to be identified at an early stage.
Timely replacement of candles is much cheaper than the repair of the catalyst or the restoration of the cylinder-piston group after detonation.
Frequently Asked Questions (FAQ)
Can I clean old spark plugs?
Mechanical cleaning (brush, knife) is strictly prohibited, as you can damage the coating of electrodes or split the insulator. Chemical cleaning or sandblasting is possible, but it is a temporary measure. It is almost impossible to restore the factory characteristics of the gap and thermal conductivity after cleaning. The savings are questionable given the risk of missing ignition.
Is it true that iridium candles last forever?
No, it's a myth. iridium Platinum has high resistance to electroerosion, which allows you to make the electrodes thinner and increase the gap. It improves flammability. However, they are just as sensitive to fuel quality, oil carbon monoxide and thermal conditions as conventional nickel. Their resource is higher (up to 100 thousand). km), but not infinite.
How often should I change the spark plugs?
Normal nickel candles are recommended to be changed every 20-30 thousand kilometers. Platinum and iridium - every 60-90,000 kilometers. However, when used in heavy urban conditions or when refueling with low-quality fuel, the intervals should be reduced by 30-40%.
Does the candle gap affect fuel consumption?
Yeah, straight. Too large a gap requires high voltage to break down, which can lead to skips spark under load (unburned fuel flies into the exhaust). Too small a gap gives a weak spark, which is worse ignites the mixture, especially on cold. The optimal gap ensures complete combustion and minimal consumption.