The oxygen or O2 sensor generally malfunctions and dies when the odometer has reached 100,000 miles. You may get additional or fewer miles out of your car, truck, or C/SUV’s O2 sensor depending on its quality. When the O2 sensor malfunctions, it causes the engine control unit (ECU) to add fuel or air into the combustion chamber when it isn’t necessary. Consequently, Speed Auto Repair advises you will notice the following problems if your vehicle needs a new oxygen sensor.
Sputtering Engine
Let’s assume for the moment that the faulty O2 sensor caused the ECU to add extra air to the combustion chamber. When this happens, the excess air causes a lean fuel mixture. Consequently, your engine will start to lag and sputter because it is being fuel-starved.
Surging Engine
The opposite of a lean fuel mixture is a rich fuel mixture. In this case, the ECU has added extra fuel to the combustion chamber unnecessarily. The chamber cannot send the fuel back so it burns it. When this happens, your engine will pick up speed unexpectedly by itself.
Poor Fuel Economy
Whether lean or rich, the skewed fuel mixture is going to reduce your automobile’s fuel economy. Unfortunately, you will need to replace the malfunctioning O2 sensor in order for the ECU to level out the air and fuel in the chamber. Until then, you will get poor gas mileage.
Rancid Exhaust
Another thing that can happen if the ECU has added fuel to the chamber is your catalytic converter may get clogged with sulfur deposits. The more fuel the more hydrocarbons in the exhaust. Consequently, the catalytic converter will malfunction and release exhaust that smells like rotten eggs.
Black Exhaust
The exhaust may also be black in color if the catalytic converter was unable to treat it. This, too, is a sign that your engine is burning too much fuel. As a consequence, the black exhaust will be filled with hydrocarbons that the catalytic converter did not treat that will increase your vehicle’s emissions.
Check Engine Warning
All of these things will most likely be accompanied by a dashboard warning light. In the case of the oxygen sensor, the ECU turns on the check engine light. It is a very rare occasion that the check engine light turns on for no reason, so head straight to our shop if the check engine light is on.
We are Speed Auto Repair in Alpharetta and Roswell, GA, and we are the only auto service shop you need for all of your vehicle’s services and repairs. Call us today if you suspect your car has a faulty O2 sensor.