Carrying out a full engine diagnostics is an event that will take a lot of time and can empty your wallet by an impressive amount. You can use modern electronic devices for diagnostics, and you can completely disassemble the engine to the screws and, armed with a micrometer, check all the dimensions and gaps that affect its work. But there is a way much easier - just the color of the spark plugs will tell you a lot about the state of the engine.

Content

• 1 Features diagnosing ICE by candle
• 2 What does the condition of the candles
• 3 Posleslovie

Features diagnosing ICE by candlelight

Inspection of spark plugs is one of the easiest ways to diagnose a motor.

First you need to understand what a spark plug is, what it is for and what its characteristics are most important. Her role in the engine is to ignite a mixture of gasoline and air entering the combustion chamber. Note that you can get the full picture only in cases with petrol engines. Diesel engines have candles in their designs, but their functions are completely different. Failure of such a seemingly insignificant element is capable of causing irreparable damage to the engine. A chain reaction usually occurs, with the result that the failure of just one candle can cost the car owner a lot. The cover of the distributor or ignition coil (or one coil, depending on the car) often breaks. Even a lambda sensor or catalytic converter can fail if any candle in the gasoline engine blows.

Note: candles are: arc, spark, glow, catalytic. Sparks are used to ignite the fuel mixture from the air and gasoline.

At a time when valves are closed in the cylinder, and the piston is in the region of the top dead center, an electrical discharge occurs between the electrodes. The current is low, but the voltage can reach 20-35 kV (depending on the type of ignition system - contact, contactless, with microprocessor control), resulting in a spark between the electrodes that can ignite gasoline. The moment of occurrence of a spark depends on the correct ignition adjustment. For normal operation, it is necessary that the timing belt (or chain) is installed with the necessary tension and the marks on the crankshaft and camshaft coincide with the marks on the block. Also important is the correct installation of the distributor, which distributes the high voltage to the corresponding candles.

See also: Which engine oils can be mixed

What does the condition of the candles

Always pay attention to the color of the electrode.

Ниже мы привели наиболее распространенные способы определить engine condition by spark plugs, а также выявить неполадки некоторых других систем автомобиля.

Picture 1. Work candle, unscrewed from a properly working motor. The color of the central electrode is light brown, there is almost no soot and other deposits, as well as traces of oil.

Figure 2. Black velvety soot. More often, this indicates a mixture over-enrichment due to an incorrectly tuned carburetor or injector, or that the air filter is clogged in the car.

Figure 3. Light gray or white electrode. In this case, the mixture is most likely supplied to the motor depleted. If nothing is done, as a result, overheating of the spark plug or the combustion chamber can be obtained, which often leads to burnout of the valves.

Figure 4. Reddish electrode color. Says that the motor for a long time runs on fuel with a large number of metal-containing additives (mainly manganese). Such a plaque conducts current more easily than the electrodes of a candle. This leads to the fact that the candle stops working.

Figure 5. Well visible traces of oil on the thread. This may be due to the poor condition of the oil caps. In this engine is often increased oil consumption. Also, immediately after the start-up, the bluish smoke rolls out of the exhaust pipe, and the engine podtraivaet, but as the engine warms up, the "symptoms" disappear.

Pay attention also to the presence of traces of oil and gasoline.

Figure 6. This candle was removed from the non-working cylinder. The skirt of the central electrode, in fact, like it itself is covered with a layer of oil interspersed with unburned gasoline, as well as with particles of damage that occurred in the cylinder. The reason may be the destruction of the valve or septum between the piston rings. This engine will “troit” constantly, and fuel consumption will increase significantly. The solution is unique - overhaul of the engine.

See also: How does a gasoline internal combustion engine

Figure 7. The central electrode and the ceramic skirt are completely destroyed. The reasons may be mass. Here are just the most likely ones: the engine worked for a long time with detonation, long-term use of low-octane gasoline, previously ignited, or factory-made spark plugs. Symptoms of the motor are approximately the same as in the previous case. If the particles of the destroyed central electrode can not slip into the exhaust system, and are stuck under the exhaust valve, the repair of the cylinder head is guaranteed.

Figure 8. The fouling of a candle's electrode by ash deposits, and their color does not matter much. Such deposits result from breakage or occurrence of the oil wiper rings (a lot of oil burns inside the cylinder). In this engine will be increased oil consumption, the exhaust will resemble a motorcycle.

Figure 9. Erosion of electrodes. Most often occurs due to the late replacement of candles or the use of fuel containing a large amount of lead. In the latter case, due to intensive chemical processes, nickel alloy electrodes are rapidly destroyed, especially under the influence of high temperatures. Such a motor works unstable, start-up is difficult, constantly “troit”, its power drops.

Carefully examine not only the electrodes, but also the ceramic insulation.

Figure 10. Candle splashed with gasoline. Often, this phenomenon occurs due to improper operation of the ignition system or injector (carburetor). In winter, the fuel may not have time to evaporate, and therefore it settles on the walls of cylinders and candles. You can try to unscrew the candles and dry them.

Posleslovie

Чтобы мотор вашего автомобиля работал без проблем, о свечах зажигания стоит вспоминать регулярно. Хотя производители свечей и дают гарантию около 30 000 км на свои изделия, диагностику их лучше производить чаще (например, при каждой смене масла). Тем более что engine diagnostics by spark plugs занимает мало времени и осуществляется без затрат с точки зрения финансов. И если менять свечи своевременно, вы избавитесь от многих проблем не только в системе зажигания, но и в системе смазки, выпуска отработавших газов, и немаловажно – сэкономите немало денег на бензине.