Plug - a device that ignites the fuel-air mixture of the engine.Color changing ceramic candle insulator, usually due to the deterioration of the engine or changing the composition of the fuel mixture on it gradually formed a deposit, which is why the black candle.For this reason, the spark are considered a better indicator of the engine.
When candles blacken equally
Why blacken the spark plug?When all the candles are black alike, the reason may be a clogged exhaust, ignition later enriched fuel mixture.About clogged muffler says increasing the concentration of harmful substances in the exhaust gas and increased reverse the exhaust gas pressure.At pre-ignition may further indicate a strong knock in the engine.If both factors are excluded, it is possible to deal in a rich fuel-air mixture.
When one candle blackens uniformly
Why black carbon deposits on the spark uneven?If blackened only one set of candles, it may indicate a malfunction of a candle, her fault or the tip of the wire, or failure o
When the candle blackens irregularly
When you have a black spark plug, the reason may be hiding in the leaky valve landing, his burning imbalance timing belt or breaking capacity of the exhaust system.In this case, a candle is black on one side only.If it blackens only the cone of the ceramic insulator and the tip remains bright, as the electrodes, means, the candle does not correspond to the engine for heat range, and it should be replaced by more hot.If the cone was clean and insulator tip is black, it means, that the candle on the contrary, too hot for this engine type.