Common Reasons An Engine Could Backfire - Toyota Service Information To Know in Salem, OR

May 9, 2019

A backfiring engine can create a loud sound that might surprise you, but that's not the worst of it. It also may mean that your engine has deeper problems that may be putting your vehicle's health at risk. The best way to handle an engine that backfires is to bring it to an authorized Toyota service center. Once there, the technicians will inspect your vehicle. The problem will likely be due to one of the following issues:

A yellow check engine light is illuminated on a vehicle's speedometer.

4. Old Engine Tech

While modern engines don't backfire much, it was a much more common occurrence in older engines. The most common cause of backfiring in old engines? Carburetors. If carburetors weren't properly tuned, they could cause backfires.

Carburetors fell out of fashion in the late 1980s, so your Toyota is unlikely to have them. But if you're rocking a vintage '60s Land Cruiser or an MR2 from the early 1980s, the carburetor might be the cause of your woes.

An image of the interior of an engine, with the crank, pistons, valves, spark plugs, & more visible.

3. Bad Engine Timing

This one is also uncommon on modern engines--but, unlike carburetor problems, it's not impossible. In order to work as it should, the internal combustion engine requires precise timing between the spark, valves, and pistons. If the spark fires too early or too late, the engine can backfire. The technicians at Capitol Toyota will check to see if the timing in your vehicle is off.

8 fuel injectors arranged in a circle.

2. The Air-Fuel Ratio Is Too Rich

These days, fuel injection is what most engines use. When everything is working as it should, the injectors put a perfect mixture of fuel and air into the combustion chamber. However, if there is too much fuel and not enough air, the mixture is too rich. If this happens, some of the fuel may remain unburned by the spark. Instead of combusting in the combustion chamber, this unburned fuel may combust in the exhaust, causing a backfire. A clogged engine air filter, bad mass airflow sensor, and leaky fuel injectors are all possible causes for a rich air-fuel ratio.

1. The Air-Fuel Ratio Is Too Lean

An air-fuel ratio that is too lean means that there's too much air and not enough fuel. Even though this is essentially the opposite of the previous problem, it can also cause backfiring by producing excessive vapor. This vapor may also combust in the exhaust. Clogged fuel injectors, a vacuum leak, or a bad fuel pump are all potential causes of an air-fuel ratio that's too lean.

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  1. Capitol Toyota

    783 Auto Group Avenue
    Salem, OR 97301

    • Sales: (888) 459-7024

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Capitol Toyota

783 Auto Group Avenue Ne
Directions Salem, OR 97301

  • Sales: 503-399-1011
  • Service: 503-399-1011
  • Parts: 503-399-1011