When the explosive noise of a car backfire occurs, it usually indicates that the air-to-fuel mixture is unbalanced or that a problem exists with the vehicle's timing. A backfire is the result of fuel burning outside to the engine's combustion chamber. Backfires can occur in either the intake system or the exhaust system, depending on the cause.
Having the proper air-to-fuel ratio in a vehicle is essential to avoiding backfires. If the fuel mix contains too much air, a backfire in the intake system occurs. If the mix contains too much fuel, a backfire in the exhaust system results. Some common causes of unbalanced fuel mixtures include leaky vacuum hoses and a malfunctioning air intake valve.
When a car backfires due to faulty timing, the first thing a vehicle owner needs to do is check both the spark plugs and the spark plug wires. Replacing these components is relatively inexpensive and often solves the problem. Another common cause of bad engine timing is an ignition distributor that requires adjusting.
A contributing factor in some backfires is a fuel filter that needs to be replaced. If this key component is faulty, it creates the perfect conditions for a backfire to occur.