"Diagnosing" cars through the condition of spark plugs

1. Brownish yellow spark plug

A spark plug with a yellow-brown color shows that the engine is operating normally, the fuel/air ratio is within technical standards and the mechanical components are stable.

If you replace a spark plug, it should have a similar heat range (with the same length of the ceramic insulator underneath). A longer heat range makes the spark plug hotter and a shorter heat range makes the spark plug cooler.

2. White spark plug

This condition occurs on many car models, indicating that the car engine is overheating. The cause of this condition may be due to unsuitable spark plugs (too large a temperature range), fuel octane rating is too low, engine ignition timing is not optimal, engine cooling system is damaged, or the engine is starved of gasoline (too much air).

In this case, it is necessary to find out the cause and fix it by trying to replace the spark plug, adjust related systems...

3. Black and dry spark plug

When checking and seeing that the spark plugs are black, it is likely that the engine is running in fuel-rich mode (excess gasoline) or the vehicle is idling too much. For models with additional black smoke coming out of the exhaust pipe, it is exactly that the engine is running in excess gasoline.

This phenomenon can be caused by a number of reasons such as: dirty air filter leading to blockage causing insufficient air supply to achieve the standard mixture ratio, broken carburetor, stuck air butterfly, weak spark plug so it does not burn all the air mixture. Before replacing the spark plug, it is necessary to adjust the appropriate air mixture ratio, clean the air filter, air butterfly...

4. The negative spark plug is badly worn.

This happens because the spark plug is affected by the additives in gasoline and engine oil.

When the above condition occurs, the engine will lose fire, especially when accelerating because the ignition gap between the two spark plug electrodes is large, causing poor ignition voltage, the vehiclealso has difficulty starting; you should replace the spark plugs.

5. Spark plugs have large spark gap

If the driver uses the spark plug for too long without replacing it, the ignition process will wear out the center electrode, increase the spark gap and reduce the spark plug's ignition ability, causing a decrease in engine power. In this case, you should replace the spark plug for better engine performance.

6. Spark plug with broken ceramic tip

Mostly due to mechanical impact, when the spark plug is dropped or heavy weight is placed on the spark plug center pole due to misuse. It can also be due to long-term use that the spark plug has deposits on the spark plug ceramic tip and center pole and the center pole is rusted.

Such spark plug condition will cause misfire, late ignition compared to fuel injection timing, reducing engine power.

7. Spark plug electrode melt

In this case, the spark plug will have a local melt at the center or a complete melt, the ceramic tip will also be pitted or cracked. The cause of the above phenomenon is due to automatic ignition causing overheating, the spark plug has an inappropriate temperature range, or other causes such as: combustible deposits in the combustion chamber, damaged coil, damaged valve, poor fuel quality; willcausing misfire which reduces engine power.

In this case, check the coil, engine, fuel ratio and replace the spark plugs.

8. Melted spark plug terminals

When the spark plug has both poles melted and foreign substances are stuck on the spark plug poles, it is due to the spark plug overheating due to auto-ignition. Pre-ignition, damaged coil, damaged valve, poor quality gasoline or combustible deposits in the combustion chamber also cause the above phenomenon.

This condition will cause loss of ignition and reduce engine power, causing damage to the vehicle's engine. You need to check the engine, fuel quality, and ignition coil before replacing the new spark plug.