Why engine backfires

Typically, a backfire takes place when one of the above explosions occurs outside your fuel cylinders. Backfires and afterfires are worth paying attention to since they can cause engine damage, power loss, and decreased fuel efficiency. The right ratio of fuel and air is critical to proper engine combustion. When an engine is running rich, it has too much fuel and too little air, which slows down the combustion process. If you think your vehicle is running rich or lean, have a trusted expert at Firestone Complete Auto Care inspect your engine.

We'll look for the following troublemakers:. In newer vehicles, computerized sensors help ensure the air-fuel ratio is correct. However, if a sensor malfunctions, it can throw off the air-fuel ratio, causing sluggish or delayed combustion.

If this is the case, your Check Engine light might be screaming at you. Leaks in the exhaust system, sometimes called vacuum leaks, can sound more like a screech than a bang as excess air gets sucked in. All this extra air mixes with the fuel, creating an incorrect ratio for proper combustion.

Even something as simple as a dirty air filter can potentially trigger a backfire. Since air filters allow clean air to flow into your engine, a dirty filter can inhibit the flow of air into the intake, creating a poor fuel-air ratio. Injectors that supply too little or too much fuel to the cylinder can also create a poor fuel-air ratio. Spark plugs that fire out of turn or not at all can also cause backfiring. Shorts in wiring, incorrect wiring, or damaged distributor caps that deliver the charge to the wrong plug at the wrong time are much more common in older vehicles.

But even in newer cars and trucks, plugs can malfunction due to carbon buildup or wear out over time. In the four-steps of engine combustion, timing is everything. If the timing is off, valves might open or close at the wrong time, and the spark might arrive early or late. Any time the fuel-air explosion is not properly compressed, ignited, and contained, a backfire can occur. Newer engines with computer-controlled timing are more reliable, and backfires are less likely.

New Zealand. Latin America. Engine Innovations. Portable Generator. Pressure Washer. Why engines matter. Petrol Lawn Mowers. Pressure Washers. Care Products. Snow Blowers. Water Pumps. Sometimes a flame can be seen when a car backfires, but mostly you will only hear a loud popping noise, followed by loss of power and forward motion. That unburnt fuel can be caused by a variety of mechanical problems, and here are some of the most common reasons for a backfire:.

If your engine is getting more fuel than it needs, a rich fuel to air ratio is the result. When your car has leftover fuel in the exhaust and the cylinders, that fuel explosively burns and creates a loud popping sound. Specifically, here we mean delayed timing, which causes the backfire.