What are the manifestations of spark plug failure?

Introduce common faults and solutions of spark plugs. When encountering spark plug problems, you can troubleshoot by the following methods.

Spark plug fault diagnosis and elimination:

The insulating part of the spark plug is light brown. This condition indicates that the engine is operating normally.

Black soot is often deposited on the spark plug electrodes. This indicates that the engine ignition time is too early, the combustible mixture is lean, the gasoline octane number is low, the cylinder is overheated, etc.

Carbon and oil deposits near spark plug electrodes. This may be caused by excessive wear of cylinders, pistons, wear of valves, valve guides, failure of valve oil seals, etc. If you need to continue driving, when there is oil accumulation on the spark plug electrode, you can temporarily change it to a hotter spark plug. In order to find out the cause in time, when the cylinder pressure meets the requirements, it is necessary to check whether the air filter, crankcase ventilation device is blocked, whether the mixed gas is too rich, and whether the engine lubricating oil is too much.

There is a small amount of carbon deposits on the spark plug electrodes, but no oil deposits. This may be due to the long service life of the spark plug, improper adjustment of the electrode gap, the general service time of the spark plug is about 16,000 km, long-term idling or low-load operation after the engine starts, and engine lubrication that does not meet the requirements.

The spark plug electrode is rounded, and the insulator has scratches and cracks. This indicates that the engine is knocking, possibly premature ignition, an overheated cylinder block, low octane gasoline, or loose air from the cylinder head, spark plugs, etc.

The insulating part of the spark plug electrode is white with brown spots. This phenomenon may be caused by early combustion in the engine, or it may be caused by the mixture being too lean, air leaking from the intake port, spark plug heat unevenness, etc. The reason for the whitening of the spark plug is caused by the overheating of the engine. If it is not treated in time, the engine will fail seriously.

The reasons for the whitening of the spark plug are: a. The calorific value of the spark plug is too high; b. The gasoline grade is low; c. The ignition advance angle is wrong (neither too early nor too late); heat sink pollution, etc.); e, the mixed steam is too thin.

Spark plug electrode insulation burnt. This can be caused by ignition too fast for a long time, too much carbon in the combustion chamber, insufficient valve clearance, a poorly working cooling system, etc.

The spark plug spark is weak. Appropriately reduce the spark plug gap, and the spark is slightly improved, indicating that the ignition coil is faulty or the performance of the ignition device is poor. It may also be low quality spark plugs, improper assembly, improper spark plug cleaning methods, damage to the spark plug electrode insulation, etc.

How to quickly judge spark plug failure?

short circuit method. With the engine idling or running at low speeds, use a screwdriver to short out the spark plugs. That is, attach the terminal nut on the upper part of the spark plug directly to the cylinder block. If there is no change in engine sound, vibration, etc., then the shorted spark plug is faulty.

Feel the temperature method. Rotate the engine for about 10 minutes. After turning off the flame, touch the spark plug ceramic core one by one with your hands, and feel that the spark plug with a lower temperature is faulty.

Trial by fire. Also known as the hanging fire method, when it is suspected that the spark plug of a certain cylinder is not working properly, the high-voltage wire of the spark plug terminal of the cylinder can be removed to keep a gap of about 4mm between the end of the high-voltage wire and the terminal; the high-voltage electricity simultaneously destroys the gap between the end of the high-voltage wire and the terminal The gap between the electrode and the electrode of the spark plug; when the engine's working condition improves, the spark plug of the cylinder is faulty.

Use the cycle method. Imported cars generally travel (1.6) 20,000 kilometers for the life cycle of spark plugs, which must be replaced after reaching the service life. Whether the spark plug needs to be replaced can be judged according to the service cycle.

visual inspection method. Directly observe whether the spark plug has cracks, damage, obvious deformation of the electrode, etc. If there is, it indicates that the performance of the spark plug is poor and should be replaced.