Ignoring the planned replacement of spark plugs is a classic example of savings that can lead to huge financial losses in the future. Many motorists perceive this consumable as something secondary, believing that if the engine starts and the car goes, then nothing needs to be changed. However, inside the combustion chamber, complex physicochemical processes occur, the violation of which is imperceptible to the eye, but destructive to the engine.
The spark plug is not just a spark-producing agent, but a high-precision sensor that determines the efficiency of combustion of the fuel-air mixture. When the part’s resource comes to an end, the spark becomes weak or unstable, causing a chain reaction of problems. At best, you’ll just spend more money at the gas station, at worst you’ll face expensive repairs. catalytic converter Or even a replacement engine.
In this article, we will discuss in detail which parts of the car are affected first, how the behavior of the car changes and why timely replacement of candles is a mandatory maintenance procedure, and not just a desire to be safe.
Engine start deterioration and trim
The first and most noticeable symptom of worn candles is a difficult start of the engine, especially in the cold season. Sparking dischargeThe combustible gas required to ignite the mixture becomes too weak to be guaranteed to set the fuel in the cylinder on fire. The engine begins to "sneeze", to spin the starter for a long time, and in the cold it may not start at all.
If one or more candles stop working correctly, the effect of trination occurs. The motor begins to work unevenly, vibrations appear at idle and under load. This is because the fuel in the idle cylinder does not burn, but is thrown into the exhaust manifold, where it can burn with cotton.
- 🔥 Unstable idling turns, floating tachometer arrow.
- ❄️ The engine will stop immediately after starting or when the gas is discharged.
- 📉 Noticeable loss of power during acceleration, thrust failures.
⚠️ Attention: Prolonged driving on the trembling engine leads to rapid failure of the engine cushions (supports) due to strong vibration, and can also damage the exhaust valves.
The situation is especially critical for diesel engines with a preheating system, although candles perform a slightly different function (incandescent), but the principle of influence on the start is similar. In gasoline engines, ignition passes are fixed by an electronic control unit, which can go into the engine. emergencylimiting the power to protect the catalyst.
Increased fuel consumption and exhaust toxicity
The fuel failure is a direct consequence of a weak spark. When the mixture does not burn completely, the efficiency of the engine falls, and to perform the same work (acceleration, maintaining speed), the system has to supply more gasoline. The driver may not notice any changes in the dynamics, but fuel It starts to grow by 10-20%, and sometimes more.
In addition to the financial losses at the gas station, this causes enormous environmental damage. In the exhaust gases, the concentration of unburned hydrocarbons (CH) and carbon monoxide (CO) increases sharply. The car begins to smoke more, and from the exhaust pipe can smell of raw gasoline.
The electronic engine control system (ESUD) tries to compensate for ignition gaps by changing the ignition advance angle and the composition of the mixture. However, the possibilities of adjustment are limited. If the candles are not replaced, the system will enter a state of constant error, which will lead to incorrect operation of all sensors, including the system. oxygenator.
Destruction of the catalytic converter
This is perhaps the most expensive risk associated with late replacement of candles. Unburned fuel, flying out of the cylinder, enters the exhaust manifold and then into the catalytic converter. There, at high temperatures, gasoline continues to burn inside the cells of the catalyst.
The temperature in this node can exceed 1000 degrees Celsius, which is critical for ceramic cells. They start to melt and break down. The resulting ceramic dust clogs the exhaust system, creating backpressure. The engine “choked”, can not effectively emit exhaust gases, which leads to an even greater drop in power and overheating.
Replacing a catalyst is an expensive procedure, often costing half the cost of a used car. Saving on candles in several thousand rubles can lead to costs in tens or even hundreds of thousands of rubles.
| Condition of candles | Combustion effect | Temperature in the catalyst | Risk of destruction |
|---|---|---|---|
| New candles | Complete. | Normal (400-600°C) | Absent. |
| Worn out (gap widened) | Partial | Increased (700-800°C) | Low. |
| A candle that doesn't work. | Absent. | Critical (> 1000°C) | High (melting) |
| Breakdown of the insulator | Unstable. | galloping | Medium. |
How to check the condition of the catalyst indiscriminately?
The easiest way is to put your hand to the exhaust pipe on a warmed-up engine. If the exhaust pressure is weak, although the engine is running at high revs, the catalyst is likely clogged. You can also use an endoscope by inserting it through the hole for the lambda probe.
Wear of the piston group and oil-removable rings
When the candle does not ignite the mixture, the fuel washes the oil film from the cylinder walls. This leads to dry friction of piston rings against the cylinder wall. Metal begins to wear out intensively, bullies appear. In the long run, this leads to rings and increased oil consumption.
In addition, unburned gasoline enters the engine crankcase, mixing with engine oil. Oil mixture loses its lubricating properties, becomes more liquid. Pressure in the lubrication system drops, which can lead to oil starvation of rubbing vapors such as the crankshaft and camshaft.
- 🛢️ Liquefying oil with gasoline, the appearance of the smell of fuel from the oil filler neck.
- 📉 Compression drop in cylinders due to wear of rings.
- 🔨 The appearance of knocking and noise in the engine when working.
Recovery of the piston group is actually a major repair of the engine. The cost of such works is not comparable with the price of a set of candles. Regular replacement of candles allows you to maintain the tightness of the combustion chamber and the normal state of the cylinder piston group.
Effects on ignition coils and high-voltage wires
The increased gap between the candle electrodes requires a higher voltage to break down. The ignition system is forced to work in extreme mode, giving the maximum charge. This puts a tremendous strain on the ignition coils and high-voltage wires.
In modern cars, where individual ignition coils are used (one per candle), the risk of their failure is especially high. Breakdown of the insulation of the coil or wire is a frequent consequence of riding on “tired” candles. Replacing coils is not a cheap pleasure, especially on multi-cylinder engines.
When replacing candles, always check the condition of high-voltage wires and coil tips. The presence of white plaque (tracks) indicates a breakdown in the insulation, and such elements should be changed along with candles.
He's also suffering. ignition Or the switchboard. Constant work at the limit of possibilities leads to overheating of electronic components and their degradation. As a result, saving on candles, you get the need to change the entire ignition system in the assembly.
Types of candles and their real resource
The service life of candles depends on the material from which the central electrode is made. Conventional nickel candles serve the least, while products using precious metals can last much longer without losing the quality of the spark.
It is important to understand that the resource declared by the manufacturer (for example, 60,000 km) is relevant only for ideal conditions: high-quality fuel, a serviceable engine and a calm driving style. In reality, especially in the conditions of traffic jams and frequent short trips, the resource is reduced by 30-40%.
- ⚙️ Nickel candles: resource 15-20 thousand km. Cheap, but require frequent replacement.
- 💎 Platinum candles: resource 40-50 thousand km. Stable spark, less char.
- 🏆 Iridium candles: resource 60-100 thousand. km. Better efficiency and durability.
Using candles with an inappropriate potassium number is also dangerous. “Cold” candles in the usual mode will overgrow with swelling, and “hot” can cause ignitionWhen the mixture is ignited not from a spark, but from a hot electrode, which leads to the burnout of the piston.
☑️ Diagnosis of candle condition
How to determine the need for replacement: visual inspection
The best way to understand what will happen if you don’t change the candles is to just twist one out and look at it. The color and state of the electrodes will tell more about the processes in the engine than any device. The normal color of the insulator is light brown or grayish-beige.
If you see black velvety soda, it indicates a re-enriched mixture or problems with the ignition system. Oily soda indicates the oil entering the combustion chamber through worn oil caps or rings. A white or melted insulator is a sign of an engine overheating or ignition too early.
Pay special attention to the gap between the electrodes. Over time, the electrodes burn out and the gap increases. Use a round probe to check. If the gap exceeds the permissible values (usually 0.8-1.1 mm, depending on the model), the spark will be unstable, even if the candle appears intact.
⚠️ Warning: Never use candles with cracked ceramic insulator. Even a microscopic crack can lead to a breakdown of high voltage on the body and failure of the ignition coil.
Regular inspection of candles (at least once every 30 thousand kilometers) allows not only to monitor their condition, but also to diagnose other engine malfunctions in time, such as problems with nozzles, valves or cooling system.
Saving on spark plugs is a false saving. The cost of a set of candles is not comparable to the risk of repair of the engine, catalyst or ignition system, which may arise due to their late replacement.
Frequently Asked Questions (FAQ)
Can I wash old candles and reuse them?
Theoretically, you can clean candles from soda using sandblasting or chemical agents, but it is impossible to restore the burnt gap between the electrodes. Washed candles can temporarily improve the engine, but their life will be extremely small, and the risk of failure of the insulator is high. A complete replacement is recommended.
Is it true that iridium candles do not need to be changed 100,000 km?
The claimed resource of iridium candles is really high, but it is relevant for ideal conditions. In practice, due to fuel quality and engine operating modes, it is recommended to change them every 60,000 km. After this period, the gap increases and efficiency drops even if there is still a spark.
What happens if you confuse the order of connection of high-voltage wires?
The engine will not start or will operate extremely unstable with strong claps in the muffler or intake manifold. The gas distribution phases and spark formation moments will not coincide. In some cases, this can cause damage to the intake manifold or throttle valve due to a reverse flash.
Does the octane number of gasoline affect the life of candles?
Yes, it does. Using gasoline with an octane number below the recommended can cause detonation and kalyl ignition, which leads to overheating and melting of the electrodes. Also, low-quality fuel often contains additives that form a conductive plaque on the insulator, causing skips of the spark.