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Automobile Spark Plug Does Not Jump Cause And Repair Method

It is difficult to avoid the phenomenon that individual spark plugs do not jump when the automobile engine is working. The power loss is often compensated by increasing the throttle opening, and the driver is generally not easy to detect. However, if two or more spark plugs do not ignite, the fuel consumption increase sharply. Exhaust pollution will also increase exponentially. To this end, it is very important to strengthen the regular maintenance. Repairing of the spark plug is necessary to avoid the occurrence of non-flashover to ensure normal work.

The Reason Why The Spark Plug Does Not Jump

The spark plug gap is not properly adjusted.

The gap is too small. It limits the contact area between the spark and the mixture gas. What’s more, it also inhibits the growth of the flame core due to the “anti-flame” effect of the electrode. Although the fire is jumped, the spark is weak and the mixture is difficult to catch fire; the gap is too large. The ignition voltage provided by the ignition system may be insufficient to cause a flashover between the spark plug electrodes.

Spark plug electrode surface area oil (attached to a layer of oil film).

This is caused by improper control of lubricating oil or gasoline. The oil accumulated in the spark plug is generally inserted into the gap between the valve guide or the piston and the cylinder wall. (wearing over-limit, the clearance is too large and the oil is smashed). The gasoline accumulated in the spark plug is caused by the excessive concentration of the mixture. Whether it is gasoline, oil or water on the spark plug, it is possible to short the electrode without jumping.

The spark plug skirt is cracked

The high voltage current breaks through the leakage from the crack, causing the electrode to not jump.

The electrode deposits carbon and the center electrode leaks to the surroundings without jumping to the side electrode.

This is because the carbon deposit (or oil stain) on the spark plug is stored too much. It will cause short-circuited, does not jump, and then burns the insulator, causing damage to the spark plug.

The electrode is damaged

The spark plug electrode is subjected to the long-term electric erosion of the electric spark or chemical corrosion of the combustion gas, which may cause the electrode to break off and fail to jump.

The spark plug insulation resistance value is too low

This phenomenon weakens the value of the ignition voltage applied to the spark gap, weakens the spark, and even completely loses the ignition function.

The high voltage wire is shorted

If the ignition coil to the distributor has a high-voltage ignition wire leakage (short circuit), the whole engine cannot be started; or the distributor to the spark plug has a leakage (short circuit), then the spark plug of one cylinder does not jump.

Platinum contacts ablate

This will cause all spark plugs to not ignite and the engine will not start and operate normally.

The spring force of the platinum contact spring is too weak

At high speeds, the contact closure time is too short or not closed, thereby causing the spark plug to have a weak spark or a lack of fire.

The electrical insulation is short-circuited and the work is invalid

The failure of the capacitor will make the distributor not work properly, and the platinum contacts will generate sparks, causing the spark plug to not jump, and the engine is difficult to start.

The ignition coil is damaged


The Spark Plug Does Not Jump The Diagnosis of The Car often Used to Check The Law


The engine is idling, the spark plug is short-circuited by a screwdriver, and the spark is broken by the cylinder. The spark plug that does not jump fire can be found, or the spark plug is removed and placed on the cylinder bore, and the spark plug core connection is tested with the end to test the fire.

No strong flashover phenomenon can be judged; whether the insulator can be touched by the hand is lower than other spark plugs to determine whether it is not working properly. Remove the spark plug and observe the surface color and electrode carbon deposit and technical condition to determine whether it is in or not. malfunction.

Spark plugs should be regularly maintained and repaired during use. If abnormalities are found, they should be repaired in time. If necessary, repair, adjust or replace new parts according to the specifications.


The selection of spark plugs should be based on engine performance and conditions of use and is generally selected in accordance with the specifications of the vehicle’s operating instructions. It should be kept clean and dry during use, the electrode is complete and free of oil, and the insulation is not damaged. Strengthen maintenance, remove carbon deposits, use them properly, and maintain their intact technical conditions to play their normal role

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