Ignition Coil Replacement
What is an ignition coil?
Ignition coils send high-voltage electricity to the spark plugs, which is necessary to start the engine. Most cars made in the past three decades have one ignition coil, or coil pack, per cylinder.
How does the ignition coil work?
There are two sets of windings inside each ignition coil. The primary windings have hundreds of turns of heavy wire, while the secondary side contains thousands of turns of fine wire.
Power supplied by the battery flows through the primary windings. When your car’s computer decides it’s time to fire that cylinder’s spark plug (or plugs), it cuts the current to the primary windings, causing the energy in them to collapse into the secondary windings. This multiplies the voltage, which is then sent to the spark plug in order to make it fire.
Oil or coolant leaks can damage ignition coils—the leaks need to be repaired along with the ignition coil.
Failing ignition coils can cause the engine to run roughly or a lack of power upon acceleration.The Check Engine Light will often flash when the engine is misfiring—continuing to drive under these conditions can damage the catalytic converter.
What are the symptoms related to a bad ignition coil?
A failing ignition coil can create several symptoms:
Check engine light comes on
Engine runs poorly or stall
Increased emissions
Reduced fuel economy
Car won’t start
If the coil is failing, you may hear arcing from under the hood, which sounds like a rubber band snapping. The ignition coil may look burned or white where the terminal connects to the insulated wire.