What are the symptoms of a bad ignition coil in a car?
3 Answers
When the following symptoms appear in a car, it can basically be determined that the ignition coil is faulty: The vehicle body shakes noticeably at idle. Observing the exhaust pipe outlet, the exhaust gas flow shows obvious intermittency, and the exhaust pipe shakes severely, with a clear "popping" sound audible. Relevant information about spark plugs is as follows: 1. Introduction: The spark plug is a crucial component of the gasoline engine's ignition system. It introduces high voltage into the combustion chamber and generates a spark by jumping the electrode gap, thereby igniting the combustible mixture in the cylinder. It mainly consists of a terminal nut, insulator, terminal stud, center electrode, side electrode, and shell, with the side electrode welded to the shell. 2. Working Principle: Under high voltage, the air between the spark plug's center electrode and side electrode rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties.
My old car had a bad ignition coil last year and it was really tough. The whole car was shaking when driving, and the steering wheel vibrated like a massage chair, making my hands numb. The engine warning light kept flashing on and off as if playing games. When stepping on the gas, the car felt like it was being held back and just couldn't pick up speed—even climbing a small hill required revving in second gear. At red lights, the engine sounded irregular, panting inconsistently. The worst part was the pungent exhaust smell, with black smoke puffing out of the tailpipe, prompting cars behind to honk nonstop. The mechanic ran a diagnostic and immediately said cylinder four had failed. After replacing the coil, it smoothed right out—this kind of issue really shouldn't be delayed.
The most obvious sign of a bad ignition coil is engine misfire and shaking. When a certain ignition coil fails, the corresponding cylinder cannot ignite and work, causing severe vibration due to engine imbalance. You may notice irregular exhaust pulses from the tailpipe, accompanied by a rotten egg smell and black smoke. During hard acceleration, the engine struggles and hesitates, with noticeable fluctuations in the tachometer needle. Experienced drivers can detect abnormal engine sounds when revving in neutral—like hiccups, with irregular rhythm. An OBD scanner will show misfire trouble codes for the affected cylinder. Immediate repair is necessary to prevent unburned gasoline from damaging the catalytic converter, which would double the repair cost.
