What are the causes of engine misfire?
4 Answers
Here are the reasons for engine misfire: 1. Excessive wear of engine cylinder liner and piston rings, poor sealing of intake and exhaust valves, and air leakage from valve oil seals leading to insufficient cylinder pressure causing misfire. 2. Poor fuel atomization due to injector wear, resulting in increased or decreased fuel quantity, or even no fuel injection causing misfire. 3. For high-pressure common rail engines, there might also be misfire caused by issues with the engine ECU. Below are the hazards of engine misfire: 1. Decrease in engine speed and power, making the engine unable to operate normally. 2. Increased fuel consumption and emission of large amounts of black smoke. 3. Accelerated wear of engine components leading to increased heat, deterioration of engine oil, and shortened oil change intervals.
Engine misfire means one of the cylinders isn't working properly, which is quite common—I've encountered it several times. The main causes include: aging spark plugs or excessive carbon buildup reducing ignition efficiency; a faulty ignition coil failing to deliver power to the spark plug; clogged fuel injectors or uneven fuel pump supply preventing fuel from reaching the cylinder; a malfunctioning crankshaft position sensor confusing the engine control unit about ignition timing; insufficient cylinder compression due to worn piston rings or leaking valves; or short circuits/open circuits disrupting electrical flow. Symptoms include severe shaking, poor acceleration, and sharply increased fuel consumption. You can read OBD trouble codes for initial diagnosis, but visit a professional repair shop promptly to avoid engine damage and safety risks—don't delay repairs too long.
Engine misfire makes the car drive like it has the shakes, and I was really worried the last time it happened. Common causes include spark plug issues—they can fail to ignite after prolonged use; the ignition coil, which supplies electricity to the spark plugs, can cause misfire if a single coil is faulty; clogged fuel injectors due to carbon buildup prevent fuel from entering and burning; critical sensors like the oxygen sensor can mislead the ECU; poor cylinder compression might indicate piston damage; and the ECU itself can malfunction, causing a cylinder to stop working. Symptoms are obvious: excessive vibration during acceleration, lack of power, and abnormal exhaust sounds. I suggest not ignoring these signs—you can try simply replacing the spark plugs, but coils and injectors require professional tools to fix. Addressing it early avoids further damage and saves on fuel costs.
Misfire refers to a cylinder in the engine not working. To diagnose the cause, start with the ignition system: check if the spark plug is worn or severely carbon-fouled—replacing it with a new one is the first step; if the ignition coil is faulty, use a multimeter to measure its resistance; a clogged fuel injector needs cleaning; a faulty crankshaft sensor may give false readings; for compression issues, inspect the piston rings or valve leakage; loose or short-circuited wiring connections should also be checked. While driving, you may experience shaking, lack of power, and increased fuel consumption. It's recommended to use a diagnostic tool to read error codes promptly upon noticing abnormalities, allowing for quick problem identification and repair.
