Spark plug, commonly known as a burner, is used to discharge pulsed high-voltage electricity sent by the high-voltage ignition coil, penetrate the air between the two electrodes of the spark plug, and generate an electric spark to ignite the mixed gas in the cylinder.
How to determine whether the spark plug needs to be replaced?
1. See if the engine can start normally
See whether the cold car starts smoothly, whether there is a particularly obvious “feeling of frustration”, and whether it can ignite normally.
2. Look at the engine jitter
Keep the car idle. If the engine can run smoothly, it means that the spark plug can work normally; if the engine is found to have intermittent or continuous shaking and makes an abnormal “chug” sound, it means that a certain spark plug may have a problem, and the spark plug needs to be replaced at this time.
3. Check the electrode gap of the spark plug
When you remove the spark plug, you will find that there is a discharging electrode in the spark plug. The electrode has a normal consumption. If the gap is too large, it will cause a normal discharge process (normal spark plug gap is 1.0-1.2mm), which will cause your engine to be weak. At this point, it needs to be replaced.
4. Observe the color.
(1) If it is auburn or rust, it means that the spark plug is normal.
(2) If it is oil-stained, it means that the spark plug clearance is unbalanced or too much oil supply is supplied, and the high-voltage line is shorted or open.
(3) If it is smoked black, it means that the hot and cold type of the spark plug is selected incorrectly or the mixture gas is thick, and the oil is running.
(4) If there is a deposit between the top and the electrode, if the deposit is oily, it means that the cylinder oil has nothing to do with the spark plug; if the deposit is black, it means that the spark plug has carbon deposited and bypassed; the deposit is gray. It is a misfire caused by the additive in gasoline covering the electrode.
(5) If the spark plug is severely ablated and the top appears scarred, black lines, cracks, and electrode melting, this indicates that the spark plug has been damaged and must be replaced immediately.

Today, I replaced the spark plug of my car with a ruthenium gold one, which is said to have a life span of more than 100,000 kilometers.