Ignition leads for your car

Your Ignition leads worn out? » Read more about common malfunctions • Repair • Replacement manual

Bringing high voltage to the combustion chamber with the ignition cable

The ignition cable connects the distributor and the spark plug, guiding the ignition voltage to the spark plug where it is converted into a powerful spark. This spark in its turn causes the explosion of the air-fuel mix, making the engine operational.

Construction of an ignition cable

The ignition cable is a thick, yet flexible copper cable with a thick rubber mantle. The thick rubber layer is necessary. 10.000 Volt runs through the cable. Without adequate insulation the voltage would leak sideways from the cable and prematurely close the circuit. No voltage would reach the spark plug and the engine wouldn't run. At its extremities the ignition cable is equipped with plugs fitting in the ignition of the car. As a rule they are not fixed with screws and can be simply pulled out.

Wear of an ignition cable

An ignition cable lasts a long time in general. However, the rubber mantle becoming brittle and porous will soon cause it to fail. Furthermore, damage to the insulation mantle occurring through external force makes the cable unfit for further use. A regular example of this kind of ignition cable damage is the bite of a weasel. Brittle rubber is an indication of an aged ignition cable. To check this, bend the cable in several places. If you see many tiny holes, the cable is aged. A weasel bite is visible by the double dental impression. In this case the cable will have one or several opposing damages in one spot.

Identifying a defective ignition cable

Damage to the ignition distribution becomes apparent through a stuttering engine or a low performance. The car no longer accelerates properly as one of the cylinders doesn’t function adequately. Fault analysis is particularly difficult in case of rodent bites. One possibility is running the engine in the dark and with opened hood. A defective ignition cable will show by blue flashes occurring sideways and running towards the engine bay. Never touch the cable in a running engine! A very strong and unpleasant shock is the result. In the worst case, you run the risk of an engine fire by driving around for too long with a defective ignition cable. Fortunately, the repair of an ignition is one of the easier repairs in a car.

Repairing the ignition

The ignition cable is one of the easiest spare parts to replace. Simply pull it out on both sides and insert the new cable. No tools are necessary. Nevertheless, ignition cables must always be replaced as a complete set. If the cause was the bite of a rodent, this is an excellent occasion to install rodent protection. An adequate and animal-friendly solution against rodent damage is e.g. ultra-sound systems. When cables are aged, the entire ignition should be checked. Distributor caps, spark plugs and even ignition coils are not very expensive and can be easily DIY replaced. A well-maintained ignition ensures quiet and safe driving and contributes to saving fuel.

Quality of an ignition cable

The ignition cable is a simple part. It should be of high-grade construction; otherwise it would not be able to withstand high voltage. Therefore, when purchasing ignition cables, only branded quality comes into question. Prices, even for the high-grade ignition cables by Bosch or ATE are really moderate. They nevertheless ensure the maximum safety of an always optimally functional ignition.