Lets talk 02 sensors and why it is important to make sure they are working.
Modern car engine control systems rely on input from several sensors to regulate the engine’s performance as well as its emissions and other vital functions. When these sensors fail to provide accurate information, the driver may experience increased fuel consumption, driveability problems, emission failures and other problems.
One of the most important sensors in modern cars is the oxygen sensor. Also known as the O2 sensor because O2 is the chemical formula for oxygen, the oxygen sensor monitors how much unburned oxygen is present in the exhaust as exhaust exits the engine. By monitoring oxygen levels, the sensor provides a means of measuring fuel mixture. The O2 sensor lets the computer know if the fuel mix is burning rich (not enough oxygen) or lean (too much oxygen). Knowing the ratio of fuel to air allows your vehicle’s engine to make any necessary changes to ensure that your car runs like it should. Your tuner can read the 02 sensors through data logging and adjust your air/fuel as needed.
Oxygen sensors are a critical component of the fuel and emissions systems because they monitor the amount of oxygen in the exhaust and transmit that information to the engine computer, which adjusts the air-to-fuel ratio accordingly. If an oxygen sensor fails, the engine computer won’t be able to correctly set the air-fuel ratio, which could result in lower fuel economy, higher emissions and damage to other components, such as an overheated catalytic converter.
Signs You Need a New O2 Sensor
An illuminated check-engine light could be a sign of a more serious issue, such as with the catalytic converter, or something as minor as a loose gas cap, so further investigation is always required. It could, however, indicate that there is a problem with your O2 sensor or even another part of your exhaust or emissions system. Any repair shop should be able to read what triggered your check-engine light, and a mechanic or auto parts store may perform this service for free.
Other signs that you need a new oxygen sensor include a rough idle, misfiring spark plugs, lack of power, stalling or a significant increase in fuel consumption. Those symptoms could also be indications of other problems, but the EPA says that replacing a bad oxygen sensor can improve fuel economy by as much as 40 percent, so clearly that is one place to look if your vehicle develops a greater thirst for gas. If your vehicle fails an emissions test, a faulty O2 sensor may be to blame for this as well.
A new oxygen sensor can cost from less than $100 on some models to $300 or more on others, but that doesn’t include labor, which can vary widely by vehicle because of where the sensors are located. As a result, the full cost of oxygen sensor replacement may vary greatly depending on the type of vehicle you drive.
The picture below shows what your going to be looking for to make sure your 02 are reading. You must have your front 02 sensors working to tune the vehicle correctly. This is a must even if you have a wideband on the car.