Denso Spark Plug Wire Set; 7mm | 6714099

Spark plug wires carry high voltage from either an ignition distributor or an ignition coil to spark plugs to create the spark needed for engine combustion. Spark plug wires, sometimes referred to as ignition wires or high tension lead, are large gauge solid copper or carbon fiber wires. They contain a conduction suppressive insulator to prevent electrical arcing, a fiberglass braid coating to prevent breaking, a rubber or silicon outer jacket to protect the wire from engine heat and fray, and an electrical connection on each end covered with a boot, one for the spark plug and one for the connection to the distributor cap or ignition coil. Spark plug wires are manufactured at just the right length to reach the spark plug and no more to reduce potential resistance that can hinder voltage flow.

Spark plug wires are capable of carrying voltage as high as 50,000 volts. Carrying this much voltage in one direction causes the electrical terminals to wear down over time. Furthermore, the rubber or silicon jacket of the spark plug wires can wear allowing the inner insulator layer of the spark plug wire to become exposed and wear, causing the wire to arc voltage to the engine, weakening the spark created by the spark plug and lowering engine performance and fuel economy.

Spark plug wires should be replaced at regular intervals along with the spark plugs, and if equipped, with the distributor cap and distributor rotor. Spark plug wire replacement intervals vary based on the auto manufacturer and can range from 30,000 all the way to 100,000 miles.

Spark plug wires can be difficult to remove and replace depending on their position in the engine bay. Special spark plug wire removal tools are available to make it easier to reach and remove spark plug wires.

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