Oftentimes, seemingly big engine problems can be traced to small sources. What might seem like a complex, costly fix might actually be pretty simple and affordable. 

In the late ‘70s and early ‘80s, car engines took a huge leap forward with the addition of a computer system. This modernization meant that engines could run much more efficiently, thanks to a number of sensors communicating with the main computer. One of the most important sensors in your vehicle’s engine is the O2 sensor. 

As its name implies, the O2 sensor is responsible for measuring the amount of oxygen leaving the cylinders as exhaust. This measurement helps the computer determine how much fuel needs to be sent, ensuring a proper fuel-to-air ratio. When your O2 sensor isn’t working properly, you’ll notice a few telling signs, such as falling gas mileage, slow acceleration, a failed emissions test, or a rough-running engine.

A common example of a faulty oxygen (O2) sensor. 
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How does an O2 sensor work?

Like the human body, an internal combustion engine depends on several different systems working together to run smoothly. Almost every After the fuel/air mixture is combusted in each cylinder, it exits as exhaust and passes through the O2 sensor. The O2 sensor reads the amount of oxygen in the fuel, which creates a voltage spike. This voltage is sent to the computer, which tells the computer if the oxygen level is too high or too low, signaling fuel that is too rich or too lean. The computer adjusts the fuel sent to the cylinders accordingly. Too much oxygen tells the computer to add more fuel; too little oxygen tells the computer to add less fuel.

Where is the O2 sensor located?

Every vehicle has at least one O2 sensor, and newer vehicles may have two. Each vehicle will have one O2 sensor located just downstream of the exhaust manifold. If your vehicle has two, the other O2 sensor will be upstream of the catalytic converter or actually in the catalytic converter.

What happens if an O2 sensor is faulty?

Like everything in your vehicle’s engine, your O2 sensor has a shelf life. Older vehicles will have about 60,000 miles before the O2 sensor needs to be replaced, while newer vehicles can make it around 100,000 miles before you need a new one. Typically, if your O2 sensor isn’t working as it should, it will throw a code triggering your check engine light. Other signals that it might be nearing the end of its lifespan include drastically worse gas mileage, a failed emissions test, black exhaust fumes, misfiring, stalling or low acceleration.

Routine Maintenance Prolongs Your O2 Sensor’s Lifespan

While O2 sensors will have a natural lifespan, there are a few things that can cause them to fail more quickly. Contaminated or dirty fuel injectors, engines that burn oil, and even a very dirty air filter can cause O2 sensors to become faulty. Dirty fuel or oil leave carbon deposits on your O2 sensor, which cause it to misread oxygen levels. Routine engine maintenance can ensure that your O2 sensor reaches its maximum lifespan. If your O2 sensor has failed, it will need to be replaced, a job that generally requires just a couple of tools and can be done yourself, or inexpensively at a shop.

SEA FOAM MOTOR TREATMENT can help keep your fuel system clean, minimizing the dirty, unburned carbon that can build up on O2 sensors, causing them to fail.

Sea Foam Motor Treatment works to clean injectors and restore factory spray patterns. It is safe and effective for all types of gasoline fuel injection systems. Using Sea Foam Motor Treatment in your gas is also a good way to ensure all components of your fuel system stay clean and perform their best.