What Is an Ignition Coil?

Almost every gasoline-powered internal combustion engine car on the market has an ignition coil. In actuality, your car most likely has one for each engine cylinder. Your engine’s ignition coil uses electrical induction to supply the high voltages required for efficient fuel burning. Although it seems like a straightforward task, it’s crucial for your car’s dependability and fuel efficiency. These coils ought to undergo routine inspection and maintenance, much like most key components.

What Is an Ignition Coil?

A basic 12-volt DC battery typically powers gasoline cars. This voltage is sufficient to activate a starter motor and start the engine, but it is insufficient to cause combustion. (For combustion, a spark plug requires about 40,000 volts.) The ignition coil has a role in this. That little current is transformed into brief bursts of many thousand volts at a time by a step-up transformer, also referred to as a coil pack. In perfect timing with the cylinder’s combustion cycle, this electricity is then sent to each spark plug, igniting fuel vapor with oxygen and generating power. Because they only employ heat and pressure to ignite their fuel, diesel engines are notable for not having ignition coils.

Modern ignition coils resemble rubber boots that a spark plug fits into. An electrical connector for receiving voltage and some threads to firmly install it on the engine are located up above. However, if you were to disassemble the part, you would find that the coil pack is made up of several meters of tightly wrapped copper wiring. These are encircled by an iron core, which functions as an electromagnet by receiving the 12V current. The energy that is supplied to the spark plug is stored in the magnetic field of the core. To prevent short-circuiting, the entire coil pack is encased in a resin insulator. Faraday’s law of induction, which is used by the ignition coil to produce enormous amounts of power, is also applicable for building electric motors and generators.

Early automobiles had just one ignition coil. A component known as the distributor, which was essentially a bundle of wires connected to each spark plug, housed this coil pack. Each gasoline ignition was likewise timed by the distributor, which over time might lose calibration and throw the engine out of whack. Automakers started adding electronic ignition timing sensors and multiple ignition coils in the 1980s to provide more power and efficiency. Nowadays, an ignition coil is mounted directly on top of each spark plug in the majority of engines. This design is referred to as “coil on plug.”

Compared to earlier distributors, these multiple-coil-pack systems are significantly more dependable, although individual ignition coils might still malfunction over time and result in an engine misfire issue. When a cylinder misfires, it signifies that the fuel within is either burning improperly or not at all. It’s also known as a dead cylinder at times. Long-term misfiring might cause more serious issues including corroded cylinder walls or bent piston rods. Unburned fuel may also leak into your vehicle’s exhaust system, which is harmful to the environment and even worse for the catalytic converters in your car. A misfire should be fixed as soon as it is discovered.

Diagnosing a Bad Ignition Coil

Over 100,000 miles is the normal operating life of an ignition coil. They might eventually break down, resulting in the dreaded misfire. This condition will usually start out gently and barely be noticed, but it will progressively get worse. Your engine computer management will probably notice a misfire when it happens, even for a brief period of time, and produce a fault code. which is when the check engine light illuminates.

You can then determine which cylinder is misfiring with a diagnostic scanner at a garage or car parts retailer, and take action from there. A choppy engine idle is yet another indication of a misfire. In extreme situations, the car could feel like it’s stalling at low speeds or surging at high RPM.

Improved gas mileage, slow acceleration, and a backfiring engine—in which unburned gasoline escapes from the exhaust system—are all indications that you have a defective ignition coil.

In addition to the coils, the surrounding spark plug, bad spark plug wires, or a bigger electrical problem are other potential misfiring causes. When you bring your car to a reputable shop, they will use a variety of voltage testing tools to determine where the circuit issue is occurring. They might additionally search for obstructions in the fuel injectors.

Ignition Coil Replacement Cost

The average cost to replace an ignition coil once you’ve found one that’s broken is $250. On top of that, labor can easily cost an additional $50 or more each coil. Since the ignition coils are typically situated in an accessible location on top of the engine and can be removed with a simple socket wrench, if you’re handy, you might want to try doing this job yourself. To be safe, simply disconnect the 12V battery first.

You might want to think about changing all of your car’s spark plugs at the same time. The misfiring cylinder’s plug may have developed corrosion or been caked with residue, and it’s definitely past due for replacement anyhow. In general, spark plugs are more difficult to access than ignition coils and must be removed from the combustion chamber using specialist sockets. Your best option if all of that sounds too hard is to look for a qualified mechanic.

A shop can easily add thousands of dollars in parts and labor to your bill with numerous ignition coil and spark plug replacement services. Your car will probably be out of operation for a few hours at the very least as a result. If the manufacturer’s powertrain warranty on your car is still in effect, getting maintenance, like replacing the ignition coil, done at a trusted shop can save you a ton of money.

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