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5 Reasons an Engine Could Backfire

Cars always seem to have an issue when you least expect it. You might be driving down the road in a rush to work when your car emits a sound that sounds like gunfire. This startling sound is your engine backfiring. If left unchecked, a backfiring engine can result in damage to your car’s exhaust or intake. Keep reading to discover five reasons the engine in your car might backfire.

car engine repaired to prevent backfiring

1. Bent or Damaged Valves

When an intake or exhaust valve is damaged or bent in some way, it won’t be able to form a proper seal as the piston rises. This could allow air and fuel back into the exhaust, where it will combust. To prevent further damage to your engine, it is important to have damaged valves replaced as soon as possible.

2. Bad Ignition Timing

The intake and exhaust valve in your engine work in concert to keep your engine running properly. These valves must open and close hundreds of times per minute at the exact right time. If the timing of either valve is off it can cause your engine to backfire.

3. Rich Air/Fuel Mixture

It takes the proper balance of air and fuel to power your engine. When too much fuel is added to the engine, it won’t burn up before the valve opens, causing a backfire as the fuel moves through the red-hot exhaust headers. Fuel injection and system service may be needed to resolve this issue.

4. Lean Air/Fuel Mixture

When there isn't enough fuel in the mixture, it burns more slowly, and this also leaves unburned gas when the valves open. This issue could be due to clogged fuel injectors so a fuel injection and system service may be necessary.

5. Incorrect Spark Firing Order

While not a common issue for newer models, if you drive an older car, it's possible that your spark plugs might be in the wrong order on the distributor. This can cause your engine to backfire.

Contact Our Engine Repair Experts

At Custom Complete Automotive, our certified technicians can inspect, diagnose, and resolve your engine issues in an honest and timely manner. To learn more about our engine repair services, or to schedule an appointment at one of our Missouri locations, contact us today!


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About the Author
Eric Riddles

Eric Riddles is an ASE Certified Master Automobile Technician who has been working as an auto mechanic since 1998 and originally joined the team at Custom Complete Automotive in 2005. Eric has numerous certifications in various aspects of car repair and spent 10 years training the next generation of auto technicians at a local high school Auto Shop classroom.

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