The stable operation of the internal combustion engine directly depends on the efficiency of combustion of the fuel-air mixture, for the ignition of which the ignition system is responsible. When a combustion chamber malfunctions, the driver often notices changes in the vehicle’s behavior, but does not always link them to the source of the problem. Ignition plugs They are a key element of this system, and their wear or pollution can lead to serious consequences, ranging from increased fuel consumption to the failure of an expensive catalyst.
Many motorists ignore the first symptoms, believing that the car is just old or the gasoline is poor quality. However, timely detection of the fault avoids more complex and expensive repairs. In this article, we will discuss in detail how to determine the condition of candles by external signs and behavior of the car so that you can quickly make a decision about replacing or cleaning.
Understanding the principles of operation and the characteristic signs of wear and tear will help you save significant money on maintenance. We will look not only at the obvious symptoms, but also at the hidden problems that are diagnosed only by visual examination or by special equipment. Ignoring these signals This can cause the engine to stop starting at the most inopportune time.
Unstable engine start and ignition skips
One of the first and most noticeable symptoms indicating problems with the ignition system is a difficulty starting the engine. If the starter cheerfully twists the crankshaft, but the engine catches only the third or fourth time, it is worth checking the condition of the candles. Weak or intermittent spark It is not able to effectively ignite the mixture, especially in the cold season or with high humidity.
Often the problem manifests itself in the form of the so-called "troin" of the engine. This is a condition where one or more cylinders are not operating at all or are not operating at all. You can hear the characteristic rattling sound of the exhaust and feel the vibration of the body. In modern electronically controlled engines, ignition passes are fixed by a control unit (ECU), which can emergency disable the nozzle of a idle cylinder to protect the catalyst.
Instability of work is especially noticeable at single turns. The tachometer arrow can jump chaotically, and the engine speed can swim. This is because the ECU tries to compensate for the ignition gaps by changing the ignition advance angle and the amount of fuel supplied, but with a physically faulty candle, software adjustments no longer help.
- 🔥 The engine is long to spin the starter before starting.
- 🔥 At idle, you can hear clapping into the muffler or intake manifold.
- 🔥 There is a strong vibration of the gear lever and the steering wheel.
- 🔥 The "Check Engine" indicator on the dashboard lights up.
If you notice that the engine starts to triple only under load (when accelerating or climbing uphill), this is also a sure sign that the breaking voltage of the candle has decreased. At the moment of a sharp opening of the throttle valve, a lot of mixture enters the cylinder, and a weak spark simply does not have enough energy to penetrate it. In such cases, replacement often helps. high-voltage or coils, but you should always start the diagnosis with a check of candles.
Dramatic increase in fuel consumption and power loss
Car efficiency is an important parameter for any owner, and its sharp deterioration is often ignored until the moment of refueling to zero. Bad spark plugs cannot ensure complete combustion of the fuel-air mixture. As a result, some of the gasoline simply does not burn and is thrown into the exhaust system, and the engine loses traction.
When the ignition is untimely or the spark is too weak, the power given off by the piston is reduced. To compensate for the loss of dynamics, the driver instinctively pushes harder on the accelerator pedal. The electronic control unit reacts to this by enriching the mixture, which leads to even more. fuel-flow. A vicious circle is formed: the worse the mixture burns, the more fuel is required to maintain speed.
The average life of conventional nickel candles is about 20-30 thousand kilometers, while iridium or platinum candles can serve up to 100 thousand kilometers. Do not focus only on the mileage, take into account the operating conditions.
The loss of power is especially noticeable when overtaking or driving with a full load of the car. The car becomes "sluggish", acceleration takes longer, and the maximum speed may decrease. It's because of the fall. compression in cylinders (if the rings have already coked from the scoop) and inefficient use of fuel energy.
It is important to note that similar symptoms can occur with a contaminated air filter or a faulty fuel injector. However, the combination of high consumption and unstable engine operation in 80% of cases indicates problems in the spark formation system. Checking the color of the electrodes during visual inspection will help confirm or disprove this theory.
Visual diagnosis: color and condition of nagar
The most reliable way to determine the condition of candles is to visually examine them. Having twisted the element from the cylinder head, we can say a lot about the processes occurring inside the engine. The color of the insulator and electrodes is a kind of “diagnostic window” into the combustion chamber.
Ideally, the central electrode and insulator should have a light brown or grayish yellow hue. This indicates the correct mixture and normal temperature in the cylinder. Any deviations from this color indicate specific problems:
- 🖤 Black dry soot (soot) is a sign of working on an enriched mixture or problems with the ignition system (weak spark).
- 🛢️ Black oily soda - indicates the entry of oil into the combustion chamber through worn oil caps or rings.
- 🤍 A whitish or melted insulator is a signal about the engine overheating or the use of candles with too low a potassium number.
- 🟥 Reddish plaque is the result of the use of fuel additives with a metal content (ferrocene additives).
Particular attention should be paid to the gap between the central and side electrodes. During operation, the electrodes gradually burn out, and the gap increases. Too much gap requires a higher voltage to break down, which puts additional strain on the ignition coil. If the gap exceeds the permissible values specified in the manual (usually 0.7-1.1 mm), the candle must be replaced.
What is a kalyl number?
The kalyl number is an indicator that characterizes the ability of a candle to remove heat. Cold candles (high potassium number) quickly give off heat and are used in forced engines. Hot candles (low potassium number) retain heat for self-cleaning longer and are put into ordinary civilian engines. Installation of candles that are not suitable for the thermal regime will lead either to their rapid engulfment with soda or to potassium ignition (ignition of the mixture from a hot electrode).
The presence of cracks on the ceramic insulator or chips is also a critical defect. High voltage leakage can occur through microcracks, especially in wet weather, which leads to ignition misses. Even if the visual crack seems insignificant, such a candle can not be exploited - it can split completely, and the ceramic crumb will fall between the piston and the cylinder, causing bullies.
Diagnostic table by appearance
For convenience of systematization of the obtained data during the inspection, use the following table. It will help to quickly compare what you saw with the possible cause of the malfunction.
| Appearance | Probable cause | Recommended action |
|---|---|---|
| Dry black garlic | Rich mixture, weak spark, clogged air filter | Candle replacement, DMRV and nozzles inspection |
| Oily black soda | Wear of piston rings or oil caps | Engine repair (replacement of rings/caps) |
| White insulator, melting. | Overheating, early ignition, poor mix | Replacement of candles with colder ones, checking the cooling system |
| Red/orange plaque | Metal-fueled additives | Changing gas stations, mechanical cleaning or replacement |
| Normal color (beige) | Engine's working. | Checking gap, continuing operation |
If oil is found on the electrodes of one candle, it makes sense to move it into another cylinder. If after starting and short work, the soda remained on the same candle, then the problem is in the detail itself (for example, a violation of the sealing ring). If the stain appeared on the candle in the new cylinder - the problem lies in the engine nodes (oil caps, piston group) of a particular cylinder.
☑️ Checklist of visual inspection
Checking sparks and high-voltage elements
If visual examination did not reveal obvious defects, but the symptoms persist, it is necessary to check the quality of spark formation. There is a "grandfather" method of checking "by mass", when the twisted candle is applied with a metal part to the engine and spinned with a starter. However, this method is not always indicative of modern ignition systems and can be dangerous for ECU.
A more reliable way is to use a special tester of spark plugs or discharger. Such devices allow you to see the quality of the spark under pressure, simulating the conditions in the cylinder. In air, the spark can slip easily, but in a cylinder where the mixture is compressed, breakdown will not occur due to insufficient coil power or a large gap.
⚠️ Attention: When checking the spark with the old method, never hold a candle in your hands and do not touch the high-voltage wire. The voltage at the output of the coil can reach 40,000 volts and above, which is fraught with a strong shock. In addition, breaking the circuit of the secondary winding without load (when the candle is simply twisted and not pressed to the mass) can penetrate the insulation of the coil.
Often, high-voltage wires are also required along with candles. Over time, their insulation dries up, microcracks appear, through which the current "leaves" to the engine body. In the dark or in damp weather, this can be seen by the characteristic glow or heard by crackling under the hood. Dielectric strength The wires must be sufficient to withstand the maximum voltage generated by the coil.
In engines where individual ignition coils are used instead of wires (directly on a candle), problems often lie in breaking the internal insulation of the coil or oxidation of the contact in the well. Oxidation of contacts is a common cause of unstable work, especially after engine washing or driving through deep puddles. Water trapped in a candle well creates a conductive path, and the spark follows the path of least resistance - by mass, bypassing the candle electrodes.
Even a new candle will work poorly if the high-voltage wire has high resistance or breaks through the mass. Always check the entire ignition circuit in the complex.
Consequences of operation with defective candles
Many drivers postpone the replacement of candles "until better times", considering this procedure to be secondary. However, a long drive with bad spark plugs is a blow to the budget and technical condition of the car. The first to suffer is the catalytic converter. Unburned fuel burns already in the exhaust manifold and catalyst, causing it to overheat and melt ceramic cells.
Replacing the catalyst is an expensive procedure, the cost of which is many times higher than the price of a set of good candles. In addition, constant ignition misses lead to gasoline getting into the engine oil. Fuel washes the oil film from the walls of the cylinders, increasing friction and wear of the piston group. This may result in the need for major engine repairs.
The ignition system itself is also suffering. Attempts of the coil to give a spark through an increased gap or through the scorch lead to its overheating and eventual failure. Ignition modules Modern cars are expensive, and their resource directly depends on the state of candles.
⚠️ Attention: If you feel a strong vibration and loss of power, do not try to accelerate the car or drive at high speeds. The operation of the engine in trigion mode under load can destroy the catalyst in a matter of kilometers, and the products of its destruction (ceramic dust) can be sucked into the cylinders through the exhaust gas recirculation system (EGR), causing bullies.
Regular candle replacement is a minimal investment in the reliability of your car. Compliance with the maintenance regulations prescribed by the manufacturer allows you to avoid unexpected breakdowns on the road. Remember that the quality of fuel at different filling stations also affects the life of candles, so when using gasoline of dubious quality, the check should be carried out more often.
Frequently Asked Questions (FAQ)
How often should I change the spark plugs?
Ordinary nickel candles are recommended to be changed every 20–30 thousand kilometers. Platinum and iridium candles last longer - from 60 to 100 thousand kilometers. However, when operating in difficult conditions (city traffic jams, short trips, low-quality fuel), the replacement interval is better reduced by 30%.
Can you clean old candles instead of buying new ones?
Mechanical cleaning (sandblasting, brushing) is possible, but it removes the spray from the electrodes, after which the candle will quickly fail. Chemical cleaning (soaking in acetone or special products) is more gentle, but does not restore the burnt gap. For a temporary solution, this is permissible, but for reliable work it is better to buy a new set.
Does the brand of gasoline affect the condition of candles?
Yeah, straight. Low-octane gasoline or fuel with a large number of additives (especially metal-containing) leads to rapid formation of soda and a change in the color of the electrodes. Using high-quality fuel with the right octane number prolongs the life of candles.
Why does he throw butter at candles?
It's a sign of engine wear. The oil enters the combustion chamber through worn oil caps (valve salvae) or stale/worn piston rings. Replacement of candles in this case will only give a temporary effect, it is necessary to repair the engine.
Can I use candles of another brand or type?
You can use, but strictly observing the parameters: thread, length, kalyl number and gap. Replacing conventional nickel with iridium is possible and even useful, but a reverse replacement (iridium for nickel) will reduce the resource. The main thing is not to experiment with the potassium number without understanding the consequences.