What Causes Flames to Shoot Out of a Car's Exhaust Pipe?
2 Answers
The phenomenon of flames shooting out of the exhaust pipe may occur due to broken copper wires in the low-voltage circuit of the car's distributor, leading to insufficient voltage. When some copper wires in the distributor's low-voltage circuit break, the ignition voltage supplied to the spark plugs becomes inadequate, resulting in incomplete combustion of gasoline. The unburned fuel-air mixture then enters the exhaust pipe, where it encounters sparks from the exhaust gases and ignites, causing flames to shoot out of the exhaust pipe. This issue can be resolved by properly reconnecting the broken copper wires in the distributor's low-voltage circuit. Other phenomena caused by broken copper wires in the distributor's low-voltage circuit: When some copper wires in the distributor's low-voltage circuit break, the cross-sectional area of the wires decreases, increasing the resistance in the primary circuit and reducing the current flow. This leads to insufficient high voltage generated by the ignition coil. When the engine is cold, although starting may be more difficult, the engine can still run normally once started. However, as the engine temperature rises, the ignition coil's temperature also increases, and its resistance rises with temperature, further reducing the high voltage generated. This results in weaker high-voltage sparks or even misfires. Due to intermittent misfires, unburned combustible mixture in the cylinders is expelled into the muffler, where it expands and encounters sparks from the exhaust gases, causing detonation. This manifests as loud bangs from the muffler.
I've personally experienced flames shooting out of the exhaust pipe. It happened after overtaking on the highway when the engine started shaking violently, followed by sudden blue flames from the tailpipe. The cause was an ignition system failure - possibly burnt spark plugs or aged coils - which allowed unburned gasoline to enter the exhaust system and ignite upon contact with high temperatures. Another potential cause is excessive fuel injection due to clogged injectors or ECU malfunctions leading to fuel over-supply. Exhaust leaks introducing oxygen make it easier to ignite unburned fuel-air mixtures. This phenomenon is quite alarming as it can not only damage the exhaust system but also potentially cause fires, especially during long-distance driving when you should immediately reduce speed and find a safe place to inspect the vehicle. Regular maintenance of ignition components and cleaning the fuel injection system can prevent such issues. Remember never to keep driving - get it repaired immediately.
