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What Could Cause a Backfire Through the Intake?

by Alex Saez

Every engine component plays a key role in your car's function, and the intake system is no exception. If the intake backfires, this is an issue that must be addressed immediately. However, diagnosing and fixing this problem requires some knowledge of the system. Understanding the intake system and the causes of backfiring will help you confirm or rule out this issue.

Intake Manifold

It is necessary to understand the intake system in order to see how backfiring occurs. The intake valve is a component of the intake manifold. The manifold is located on the top of V6 and V8 engines. For inline four- or six-cylinder engines, the intake manifold is installed on the side. The manifold's job is to provide a mixture of air and fuel to the engine's cylinders. To do this, the intake valve opens to draw gas and air into the engine. After opening, the valve closes to keep this air and fuel combination trapped inside.

Cause of Backfiring

Backfiring is a small explosion. Although there are many problems that can cause the intake system to backfire, the overall effect is the same. Since the intake valve needs to provide the engine with a proper balance of fuel and air, a backfire occurs when that balance fails. In this case, having less fuel than air in the mixture will cause the small explosion. Luckily, this does not result in serious damage.

Main Cause

Engines are full of components, many of which can malfunction to trigger a backfire. The most common reason for this is a faulty fuel system. The fuel system consists of three components: the vacuum, the airflow sensor and the oxygen sensor. All of these parts are responsible for maintaining the air-to-fuel balance in your engine. If any of the parts are damaged or defective, backfires can occur.

Other Causes

A leak in the air injection system can also cause the intake to backfire, since this affects the amount of air taken in. Another possible reason is a malfunctioning fuel pump or obstructed air filter. The intake system must be timed correctly so that it can feed fuel and air to the spark plugs at a proper rate. If this timing is off, it can be another cause for backfiring.

About the Author

Alex Saez is a writer who draws much of his information from his professional and academic experience. Saez holds a Bachelor of Arts in English literature from Queen's University and an advanced diploma in business administration, with a focus on human resources, from St. Lawrence College in Kingston, Ontario.

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