What Causes a Car to Backfire on Acceleration and How to Fix It Easily

So, what is Backfire? Backfire occurs when the engine works and can happen in the air, fuel intake, and exhaust gas line. But now, backfire is rare because many modern cars use the Electronic Fuel Injection (EFI) system.


The EFI system can reduce the risk of backfire because it has a good ignition process, fuel supply, and interdependent emission control. However, the injection system does not adequately protect the car from backfires.

What Causes a Car to Backfire on Acceleration?

A car backfires in acceleration can be alarming, not to mention potentially dangerous, especially if they occur while driving. They are usually accompanied by a loud popping or cracking sound from the vehicle’s exhaust system, which may cause the engine to stall or misfire.

Backfires occur when the fuel-air mixture in the engine’s combustion chamber ignites outside the normal ignition sequence. This can be caused by a variety of factors, including:

  1. Engine Timing: If the engine timing is incorrect, the fuel-air mixture may not ignite correctly, causing backfires. This can be caused by a faulty timing belt or chain or even improper installation of the timing components.
  2. Fuel Pump: A failing fuel pump can cause a lean fuel mixture, leading to backfires. This is because the engine isn’t receiving enough fuel to combust properly.
  3. Check Engine Light: If the check engine light is on, it could indicate a problem with the engine’s airflow, fuel delivery, or ignition system. These issues can lead to backfires.
  4. Distributor Caps: The distributor cap distributes the electrical current from the ignition coil to the spark plugs, and if it is damaged or worn, it can cause misfires and backfires.
  5. Exhaust System: A clogged or damaged exhaust system can cause a build-up of pressure in the engine, which can cause backfires.
  6. Air Flow: Insufficient airflow to the engine can cause backfires. A clogged air filter, a malfunctioning mass air flow sensor, or a faulty throttle body can cause this.

If your car is experiencing backfires, it’s important to have it checked by a qualified mechanic. Ignoring the issue can further damage the engine or other components.

Depending on the cause of the backfires, the mechanic may need to perform diagnostic tests, such as checking the engine timing, fuel pressure, or ignition system components.

First, backfires can be prevented by following the manufacturer’s recommended maintenance schedule, including regular inspections of the fuel system, ignition system, and exhaust system. This can help catch any issues early on before they lead to more serious problems.

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Overall, understanding the causes of car backfires, and taking steps to prevent them, can help ensure a safer and more reliable driving experience.

During routine maintenance, checking the condition of each combustion part of the car engine is essential to ensure which sections must be replaced so that the engine functions normally.

Intake explosion usually occurs due to incomplete mixing of fuel and air because there is very little fuel.

As a result, when the exhaust valve opens to start the exhaust process, the heat will face slow fuel that can’t burn.

So, when the heat temperature starts to burn fuel, simultaneously, the intake valve opens for suction and then delivers a mixture of new fuel and air. The result is explosions whose flames can instantly ignite and spread to the air filter.

Exhaust backfire occurs due to unburnt fuel in the combustion chamber and only burns after being discharged to the exhaust manifold, which is very hot. Exhaust backfire also occur due to wrong or late ignition timing. As a result, unburnt fuel and air will lead to the hot exhaust, and explosions occur.

So those are the eight factors that lead to a car backfire.

What are the Problems Caused by Backfire?

Backfire can cause several problems, as below:

    • Engine power is lost: every explosion in the combustion chamber generates enough power for the rotating engine shaft. The engine loses its rotating ability if explosions do not appear in the combustion chamber.
    • Wasteful of fuel: Every drop of fuel is expected to be the power to turn the engine shaft, but that does not happen
    • Damage to engine components: Intake hose breaks, torn air filters, exhaust leaks, etc.

How to Overcome Backfire on Your Car

So, I will provide information based on personal experience when my car experiences a backfire. At that time, my car engine was working rather harshly and was vibrating a little when the car engine reached its working temperature.

When I drive, it gets stuck at 2,500 Rpm, and when I step on the gas pedal deeper, there are popping sounds in the engine room and the exhaust simultaneously. So, why does my car backfire?

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Based on various information from mechanics who understand the engine well, almost all say there are some ignition or ignition timing issues.

After I checked, I found a spark plug cable was torn, and I fixed it. However, a backfire still happens, and the engine loses power. Then I tried to replace the ignition coil, adjust the valve, and change the engine oil, but the results were the same. Likewise, when I checked the engine compression, all conditions were right.

Then I decided to replace the spark plug again. But when the car had just covered a distance of about 2 Km, it turned out that spark plugs numbers, 1,2, and 3 turned black, while spark plugs numbers, 4,5, and 6 were still pure white, and that’s a perfect combustion sign.

So I found that the black spark plug was a sign that the fuel wasn’t burning correctly because of the imperfect Fuel Injector spray. Then I tried to clean the Fuel Injector in a regular workshop with an Ultrasonic Fuel Injector Cleaner engine. You can also use the TOP 1 Power Booster 500Ml for gasoline or diesel cars.

When the fuel injector was tested, it turned out that injectors number 1,2, and 3 only sprayed half the other nozzles’ gas.

As a result, the mixture of gasoline and air becomes very lean so that the gas does not burn, and the mixture will burn in the Exhaust Manifold and cause a backfire. After cleaning the fuel injector, I reinstall it in the car using the new O-Ring Injector.

As a result, the car’s engine has become smooth and very powerful. Yet at that time, the fuel injector’s age in my car’s engine was still relatively new, around nine months, and everything was replaced with a new one. However, dirt on the gas tank that passes through the gasoline filter turns the fuel injector clogged.

After fixing ‘everything,’ I immediately did an emissions test, so that fuel combustion was even better, and the result was the performance of my car returned to normal. I could drive to travel long distances.

Well, that’s my experience when fixing a backfire in my vehicle.

Hopefully, information about what causes a car to backfire on acceleration can be useful for you.

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