Why Does a Malfunctioning Oxygen Sensor Cause Black Exhaust?

A malfunctioning oxygen (O2) sensor can cause black exhaust by indirectly affecting the balance of air and fuel in the combustion chamber. The oxygen sensor measures the oxygen levels in your car, truck, or utility vehicle’s exhaust. If it is going bad, it will be unable to measure the oxygen levels or measure them incorrectly. Consequently, the engine control module (ECM) may increase the amount of fuel in the combustion chamber unnecessarily. Total Auto Care explains this is what causes the black exhaust.

Performance Trouble

This will also cause engine performance problems. Your engine will surge and pick up speed unexpectedly and erratically. This is because it is burning away the excess fuel in the combustion chamber. If the faulty O2 sensor causes the ECM to put too much air in the chamber, your vehicle’s acceleration will hesitate and your engine will sputter as you drive your automobile.

Fuel Efficiency Loss

Either condition will cause fuel efficiency loss in your automobile. You will simply not get the fuel mileage you normally get and will have to fill your tank more often. With fuel prices on the rise, this can create a huge problem for those on a tight budget. Unfortunately, the only way to resolve the issue and restore your fuel economy is to replace the malfunctioning O2 sensor.

Rotten Egg Odors

As the O2 sensor goes bad, it can also indirectly cause problems with the catalytic converter. In this case, the excess fuel in the combustion chamber creates excess exhaust that the converter must treat. Consequently, the catalytic converter will eventually get clogged, and, as a result, malfunction. A faulty catalytic converter will release a rotten egg odor into your vehicle’s exhaust.

High Emissions Levels

The excess fuel will also increase your automobile’s emissions levels. This is bad news for people who live in a state that requires emissions testing to register their automobiles. Until you replace the oxygen sensor, your vehicle will be unable to pass the emissions test.

Check Engine Warning

Finally, your vehicle will also fail the emissions test because your check engine light will be on. When the O2 sensor fails, it sends an error code to the ECM. The ECM cannot repair the oxygen sensor. Consequently, it will turn on the check engine light and leave it on until you replace the oxygen sensor.Total Auto Care in North Branch, MN, is here to help, so give us a call today. We can test your oxygen sensor and replace it if necessary.