Wondering Why?

Why Do Engines Backfire?

Why Do Engines Backfire?

Backfire occurs in the automobile engine due to the failure in maintenance of air to fuel ratio. If the carbureted engine has inadequate fuel compared to the air, backfiring occurs. Backfire can also occur when there is any problem with the emission system. If the exhaust system is accumulated with fuel that is unburnt then it gets ignited there itself and results in backfire. The backfire can be avoided by providing correct percentage of fuel to the air-fuel mixture in the engine.

The backfire causes can be addressed by solving the fuel imbalance. Monitoring of the vacuum leak, modifying the airflow sensor and oxygen sensor and checking the fuel filter properly can minimize the problem of backfire. The air injection system that precedes the exhaust system in the air passage loses air due to some leakage. This leads to the fuel that is not utilized in combustion to explode abruptly. This will result in backfire. The main reason for this sequence of events to happen is intake of struck air by the exhaust manifold.

Normally a combustion engine in a vehicle can have many sequential explosions inside its chamber. Sometimes the explosions also get extended to outside of the engine chamber, like in the intake valves or in the exhaust chamber. The explosions that occur outside the engine might result due to the burning of fuel in the engine before the intake valves are completely closed. The explosions may also result due to movement of the fuel into the exhaust chamber. During the time of these explosions a strong flame will come out from the exhaust pipe accompanied by a loud sound. This is referred to as backfire.

The backfire might result because of fuel system related issues or issues related to engine timing or problems with catalytic converter. The imbalance in air/fuel ratio can occur due to the removal of catalytic converter. Due to all the above reasons engines backfire.


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