How to buy ignition coils wisely

How long do ignition coils last and the reasons they fail

Without an ignition coil, the spark-ignition (petrol) engine would be unviable. They provide the high-voltage necessary to create the spark that ignites the petrol and air mixture, using the car battery and re-charging system. While older vehicles tended to have a single coil, most designs today have one for each spark plug.

Is it okay to use aftermarket ignition coils?

Should your engine suffer from a faulty ignition coil, you do not have to buy a replacement part from a main dealer. A well-known, branded aftermarket component, sourced from a reputable supplier, will offer a high-quality solution, often at a reduced cost.

How long do aftermarket ignition coils last?

A good quality, branded aftermarket ignition coil should last at least as long as the genuine part that was fitted to the vehicle at the factory.

Yet, low-quality replacement coils are entering the market, especially online. While substandard coils cause misfiring and difficult starting, using them can increase fuel consumption and even cause damage.

What brand of ignition coil is best?

The worst ignition coils tend to be those that are either counterfeit, or whose origins are unknown. Therefore, avoid parts supplied in unbranded white boxes, supplied through an unknown seller on a generic online marketplace.

Why do ignition coils fail?

A popular cause of ignition coil failure is high electrical resistance.

Not replacing spark plugs on time, ignoring oil/water ingress around the ignition system components and not renewing other worn ignition system parts (such as leads and distributor caps/rotor arms on older cars) increases the voltage demand on the coil. Should a misfire occur, the pent-up energy within the coil is released as heat, reducing its lifespan. Naturally, this situation courts premature ignition coil failure.

Why are ignition coils so expensive?

These are precision components. As a typical spark plug is fired eight times a second, ignition coils have to be well made.

Being tempted by a low-quality part is a false economy. As coils are controlled by the engine management computer (ECU), they send low voltage references back after the spark plug has been ‘fired.’ Unfortunately, on poor-quality parts, these voltages can be excessively high, which can damage the ECU’s ignition drivers and, therefore, destroy the engine management computer.

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