Knowledge of common problems of auto spark plugs

When it is found that there are scars or damage on the top of the auto spark plug, and the electrode is melted or ablated, it indicates that the spark plug has been damaged, and the spark plug should be replaced at this time. During the replacement process, you can check the ablation of the spark plug and the color change. Sometimes deposits will stick between the top of the spark plug insulator and the electrode. When the deposit is severe, the engine may not work properly.
So what are the common problems with spark plugs?
1. The electrode is melted and the insulator is white. This phenomenon indicates that the temperature in the combustion chamber is too high. This may be caused by too much carbon deposit in the combustion chamber, which causes the valve clearance to be too small, which further causes the exhaust valve to overheat or the cooling device to work poorly. When the spark plug is not tightened according to the specified torque, it will also cause the electrode to melt and the insulator to appear white.
symptom
2. The electrode becomes round and the insulator is knotted, which indicates that the engine is prematurely ignited, which may be caused by premature ignition time, low octane number of gasoline, and high calorific value of the spark plug.
3. The top of the insulator is broken. Generally speaking, knocking combustion is the main reason for the cracking of the insulator. However, premature ignition, low octane number of gasoline, and high temperature in the combustion chamber may all cause engine knocking and burning.
4. There are gray and black stripes on the top of the insulator. The appearance of these stripes indicates that the spark plug has leaked, and the owner needs to replace it with a new one unconditionally.
5. There are oily deposits on the spark plug. When oily deposits appear on the spark plug, it means that the lubricating oil has entered the combustion chamber. If only a few spark plugs have oily deposits, it may be caused by damage to the valve stem oil seal, but if the deposits are stuck to the spark plugs of each cylinder block, it indicates that the cylinder has oil spills. Generally speaking, when the air filter and ventilation device are blocked, the cylinder is very prone to oil leakage.
6. There are black deposits on the spark plug, and there are black deposits on the spark plug electrode and inside, which usually indicate that the mixed gas in the cylinder is too rich. Owners can crank up the engine speed for a few minutes to burn off a layer of black soot left on top of the electrodes.
7. When disassembling, remove the high-voltage branch wires on the spark plug in sequence, and mark them on the original position to avoid installation misalignment. During the disassembly, pay attention to remove the dust and sundries at the spark plug hole in advance to prevent the sundries from falling into the cylinder. When disassembling, use the spark plug sleeve to hold the spark plug firmly, turn the sleeve to remove it, and arrange them in order.
8. The normal color of the electrode of the spark plug is off-white. If the electrode is burnt black and has carbon deposits, it means that there is a fault. During the inspection, connect the spark plug to the cylinder block, touch the terminal of the spark plug with the central high-voltage wire, and then turn on the ignition switch to observe the position of the high-voltage electric jump. If the electric jump position is in the spark plug gap, it means that the spark plug works well, otherwise, it needs to be replaced.
9. Adjustment of spark plug electrode gap The spark plug gap of various models is different.
Generally, it should be between 0.7-09. Check the size of the gap, which can be carried out with a spark plug gauge or a thin metal sheet. If the gap is too large, you can tap the outer electrode with a screwdriver handle to make the gap normal; if the gap is too small, you can use a screwdriver or a metal piece to insert the electrode and pull it outward.
10. How to check the spark plugs of auto, the model of spark plugs produced in China consists of three parts of numbers or letters. The number in front shows the diameter of the thread, such as the number 1, which shows that the thread diameter is 10mm, and the letter in the middle shows the length of the spark plug screwed into the cylinder: the last digit shows the thermal type of the spark plug: 1-3 is the thermal type, and 5 and 6 are the thermal type. Medium-sized, above 7 is cold type.