Picture this; you are driving into a highway with a smile on your face and your favorite FM on the radio. Suddenly the engine decides to screech in complain and sputter smoke.
What do you make of that? There could be many reasons for such an impact. You cannot determine the cause without understanding what is happening.
An O2 sensor is one of those tiny but intricate devices that keeps the engine in control. You will know further about it in the following section.
The question is, will a bad o2 sensor cause misfire or not? How will you identify it, and what should be your next step? Pause everything that you are doing and take a peek!
Functions of an O2 Sensor
An O2 or oxygen sensor is a petit device but weighs the heaviest during the performance.
Let me ask you one thing – what do you think happens to the fuel as you drive? It feeds the engine but is that all it does? No, the engine cannot work properly unless the engine emits the right amount of oxygen too.
It is sometimes known as the air-fuel ratio in the engine term; it adjusts the fuel injection to air for a smooth drive.
Now, what does an oxygen sensor do? Simple, it measures the air level or O2 level in the exhaust pipe. Hence, you will find this component in the engine’s exhaust system.
Another question may arise now – does that mean the air-fuel ratio remains the same at all times? Technically, no, oxygen sensor delivers the measurement to PCM (Power Control Module), where the systems decide to work together efficiently.
It is when the measurement provides wrong data, the result is due to a bad O2 sensor.
Can Bad O2 Sensor Misfire?
Now, to answer the million-dollar question in short, yes, the oxygen sensor can cause a misfire to the engine.
Once again, this component is adorably tiny, but its roles are massive. While the engine has its functions to look after, the sensor ensures combustion intervals, engine time regulation, delivers the air-fuel ration measurement, etc.
These are only the major factors determined once the sensor transmits the data. So, if this device goes faulty, you can imagine many related issues springing, including misfires in the engine.
Many other performance issues may arise aside from misfiring. Have you ever experience sudden power loss? Or hesitant, stalling of the engine as it runs?
If you did not know then, you know now that an improper oxygen sensor might the source of it all.
Identify the Symptoms of a Bad O2 Sensor
This is no tool that will alert you of its malfunction. You will have to read the signs the car sends you. Here are some notable ones you can check out.
Is the Engine Light on?
A driver must always check the engine light. Consider this as the shortcut method to learning something fishy is happening to the sensor.
So glance at the engine light occasionally to make sure it is not blinking or on. The blinking indicates a bad O2 sensor trying to drag itself to make it to the end.
Nevertheless, do not always assume it is a bad oxygen sensor and decide to fix it yourself. Sometimes, engine light blinking can occur due to other issues. It is a complicated matter, honestly.
The wisest decision is to take it to the workshop or call an expert for a thorough check-up.
Is it Smelly?
Do not laugh at this symptom, for it is another way of figuring out a bad day for the oxygen sensor.
Have you ever encountered the smell of a rotten egg? It is unbearable! You might notice a somewhat similar odor coming out as the air-fuel ratio goes berserk. This should be a warning sign by the engine pleading to take it to the workshop.
Too Much Black Smoke?
Another way to figure out an oxygen sensor malfunction is the black, somber smoke in a substantial amount. And it will rise high too – visible to everyone’s eyes.
However, this does not mean you should panic every time the exhaust system emits black smoke.
You have to learn the differences. It is okay for such smoke to come out slightly but to emerge in a higher amount is what you should worry about.
How Poor is the Gas Mileage?
Are you experiencing a sudden reduction of mileage compared to the fuel you have just filled? It is a pondering matter.
Why does that mean the O2 sensor is playing up? The sensor’s job is to read the air-fuel ratio properly. However, a bad oxygen sensor fails to read the data accurately, injecting more fuel to the engine than required.
So, the mileage begins to drop no matter what you do.
This is one of the conditions caused by a bad O2 sensor; do not delay the inspection in this regard!
How Rough Idle is the Vehicle?
An engine can misfire even when the car is in idle mode. Suppose the engine light shows lean, meaning the fuel injection is lower than the oxygen.
The lack of fuel disrupts the reaction necessary in the chamber and eventually misfires in the engine.
One way to identify the faulty sensor is if idling is rougher. Is it causing too much vibration or shakiness? It is not normal, so have a professional look at your engine or the O2 sensors.
Installation Guide of a New O2 Sensor
One should not deal with the installation process unless he/she knows what to do. In any case, this O2 sensor replacement procedure should give you an idea about how to begin.
1. Lift Vehicle
Use a jack to raise the car high enough for you to work on the oxygen sensor replacement. Make sure it is well secured. The sensor is found in the exhaust system. Now apply lubrication to the part before beginning.
Furthermore, it would help if you learned how to read the ODBII codes of the scanner tool to find out which sensor is faulty.
2. Disconnect the Connector
You are going to need some basic tools to disconnect the wiring. The bottom line is you will have to locate the malfunctioned O2 sensor and take it out from the harness.
3. Take out the Sensor
Now slowly work on removing the sensor entirely. You will require an O2 socket or a wrench. Loosen the sensor by unscrewing counterclockwise. Then you can easily remove the component with your hand.
4. Compare
Before you install the new oxygen sensor, you have to compare it to the faulty one. It is to ensure the wires and connector end is of the same kind, and everything is equally fitting.
Sometimes the style might look slightly different and lack complete precision. But it is alright so long the fitment requirements are accurate.
5. Install the New Oxygen Sensor
Now reverse the removal procedures of the faulty oxygen sensor in your mind and start installing the new one. It is better to treat the threads with lubricants for a smooth process.
Do not forget to check whether everything lines up or not in the harness. Zip tie the wires if required to avoid burns, snags, chafes, etc.
6. Clear Trouble Codes
Finally, connect the OBD II scanner tool and work on clearing the trouble codes. Now put everything back in order and start the engine. See if the engine light has turned off.
This means the O2 sensor issue has been resolved. It will additionally eliminate other symptoms experienced by the bad oxygen sensor.
And contact an expert in case you are in doubt or want a professional to handle it.
When is the Right Time for O2 Sensor Replacement?
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Whenever you notice the vehicle acting up with the symptoms above, please make a note and take it to the workshop as soon as possible!
The longer you take, the more you are endangering the engine life. Besides, driving with a bad oxygen sensor means excessive emission to the atmosphere.
In short, you are practically piercing the atmospheric shield with your own hands. On the other hand, it is tiresome to drive with a bad fuel mileage vehicle that does not run smoothly.
Now, when is the ideal time to replace the O2 sensor officially? Better to do it when you have driven 60k to 90k miles. You usually inspect its condition before coming to a conclusion.
It is wise to check it more frequently if your vehicle model is about 15 years old.
Final Words
Honestly, there could be many reasons why an engine misfires. It does not always have to be the O2 sensor. However, it is better to check than be sorry in the middle of nowhere.
My advice is to keep a spare in the car; you never know when it will come in handy! Take the vehicle to the mechanic once in a while if it is complex to understand engine maintenance.
Please, have it inspected and repaired to drive efficiently without losing fuel at short mileage. Lastly, do not stall repairs for the future!
Best of luck.
