What happens when the engine coil is broken?

[VanAmy]

There are three manifestations of a faulty engine ignition coil: 1. At idle, the vehicle body shakes noticeably; 2. While driving, when the RPM is below 2500, the vehicle body shakes noticeably with weak acceleration; 3. Upon opening the engine hood and observing the running engine, noticeable shaking of the engine is observed. Causes of ignition coil failure: 1. A short circuit in the spark plug can directly cause an increase in current in the ignition coil, leading to a short circuit; 2. An open circuit in the spark plug (excessive carbon buildup) can increase the load on the ignition coil, causing it to fail after prolonged overload operation; 3. A short circuit to ground in the high-voltage wire can cause an increase in current in the ignition coil, leading to a short circuit.

[LaAlan]

A faulty engine ignition coil can cause a lot of trouble. I've experienced it on my own car—the coil is responsible for converting low voltage into high voltage for ignition. Once it fails, the spark plugs won't ignite, and the engine starts shaking, loses power during acceleration, and feels like it's wobbling drunkenly. The ride becomes rough, fuel consumption spikes, and black smoke comes out of the tailpipe. If not fixed promptly, the catalytic converter can get contaminated and damaged, leading to even higher repair costs. During diagnostics, the OBD scanner often shows error codes like P0300 for misfires. I recommend not driving it hard and replacing the coil immediately. Usually, only one fails, but replacing the whole set can prevent other aging issues, saving money and hassle in the long run. Ignoring it for too long can also affect engine lifespan.

[RicardoLee]

As an ordinary driver, I once experienced a bad ignition coil during my daily commute. The car suddenly felt sluggish, jerking during acceleration as if the engine was stuck. At red lights, the idle vibration was severe, and the engine light on the dashboard lit up. The reason was ignition failure, wasting fuel without proper combustion. Fuel consumption soared, costing me dozens more per month. Highway driving was the most dangerous—lack of power made overtaking difficult, increasing accident risks. The mechanic told me replacing the coil is simple, costing just a few hundred yuan. Remember to regularly check dashboard warnings and fix issues early for safety. Don’t let minor problems escalate—delaying repairs harms the car more.

[DelLevi]

Coil failures are common during car repairs. A faulty coil can cause engine misfires, with obvious symptoms: sluggish acceleration, engine shaking, and strong vibrations. Fuel consumption can spike by over 20%, and the catalytic converter is prone to damage. Diagnosis is quick—use an OBD tool or perform a coil pull test to identify the non-firing cylinder and replace it. Be cautious with wiring harnesses during replacement to avoid short circuits. Neglecting repairs can lead to chain damage to spark plugs. Owners shouldn't skimp on small costs—act promptly.