Temporary Fix For Bad O2 Sensor: Signs Of Gone-Bad Sensor

An oxygen sensor is an electronic device that measures the air-fuel ratio within the car’s engine and adjusts it to the optimal situational value. It’s one of the most critical sensors a vehicle can have, and its malfunction can lead to numerous issues. In this article, we’ll focus on a temporary fix for bad O2 sensor and the symptoms of a bad O2 sensor.

How Does the Oxygen Sensor Work?

Before we move on to the symptoms of bad oxygen sensors, let’s first look at how an O2 sensor works.

An O2 sensor functions by measuring the oxygen levels in the exhaust flow and comparing them to the outside levels. It then sends an electrical signal to the powertrain control module, telling it how to adjust the fuel-air mixture.

The electrical signal is generated by a chemical reaction caused by the difference between the oxygen levels within the exhaust and outside. The low-level voltage generated ranges between 0.1 and 0.9 volts, with a reading below the 0.45 V mark indicating a lean fuel mixture and a reading above the 0.45 V mark indicating that the fuel is burning rich.

Symptoms of a Faulty Oxygen Sensor

Like most car components, oxygen sensors tend to give out after a while. Although a failing oxygen sensor doesn’t necessarily mandate replacement, symptoms of a bad O2 sensor can be inconvenient and annoying, at the very least. Here are the most common signs of a bad oxygen sensor.

Illuminated Check Engine Light

A flashing check engine light can mean many things, including a bad oxygen sensor. Although an O2 sensor can’t trigger the “check engine light” on its own, it can lead to the failure of other engine systems, which, in turn, can.

It’s always best to let a professional diagnose the issue.

Overheating engine

An overheating engine is typically a sign of something wrong with the cooling system, but in some rare instances, it can also be attributed to a faulty O2 sensor.

If the engine overheats because the oxygen sensor can’t regulate the air-fuel mixture, then the vehicle’s owner has likely failed to notice the early warning signs of a failing oxygen sensor. In such instances, the broken oxygen sensor is likely too damaged to be saved, necessitating oxygen sensor replacement.

Rough idling

Many things, including fouled spark plugs, faulty fuel injectors, and other failing exhaust system components, can cause rough idle. Since an O2 sensor plays a pivotal role in engine timing and ensuring optimal combustion intervals, it can also lead to rough idling.

You should be able to recognize rough idling without too much fuss, as your car will grind loudly when you try to accelerate.

It’s best to address the issue before the rough idle turns to engine misfires and stalling. Ruling out a faulty spark plug and fuel injectors is the best action here. If these components check out, then it’s time to move to the O2 sensor.

Poor engine performance

Aside from rough idling and excessive oil use, bad oxygen sensors typically lead to weak engine performance. The oxygen sensor’s inability to regulate the air-fuel mixture will lead to engine combustion and timing disruptions and, in turn, to poor engine performance.

Addressing weak engine performance is imperative before the problems become more serious.

Poor gas mileage

High fuel consumption is another symptom of a bad oxygen sensor accompanying a poor-performing engine.

When an O2 sensor starts failing, your car typically compensates by injecting too much oxygen or fuel into the engine’s combustion chamber, which leads to a drop in fuel efficiency.

Excess fuel in the car engine can lead to an unpleasant rotten egg smell and black exhaust fumes from the exhaust pipe. It can also lead to catalytic converter damage or even failed emission tests.

Sudden catalytic converter failure

As a part of the vehicle’s emissions system, catalytic converters split the molecules of harmful engine exhaust gasses and convert them into less dangerous gasses and their by-products.

A catalytic converter relies on an O2 sensor to provide the correct air-fuel ratio reading; a malfunctioning oxygen sensor won’t be able to do that. This can lead to excess fuel in the combustion chamber, which can’t burn properly and might clog the catalytic converter, leading to sudden catalytic converter failure.

Failed emissions test

By regulating the vehicle’s air-fuel mixture, an O2 sensor also plays an important role in reducing the pollutants emitted through the exhaust system.

Emission tests can’t be passed with one or more of your oxygen sensors going bad, which makes the emissions testing process arduous and the faulty oxygen sensor replacement mandatory at some point during emission testing.

Engine noises

Engine noises can be attributed to numerous malfunctioning vehicle components, and a bad O2 sensor is no exception. Failing to regulate the oxygen concentration in the fuel-air mixture, a faulty oxygen sensor will lead to excess carbon buildup within the vehicle’s engine.

The engine will develop knocking or pinging noises depending on whether the sensor is providing a lean (lower proportion of fuel) or rich (higher proportion of fuel) mixture. If the noises occur while the car is idling, there’s a high chance the problem lies in one, more, or even all the sensors.

Temporary Fix for Bad O2 Sensor

Although an important exhaust system component, the oxygen sensor isn’t critical to the vehicle’s functioning. With that in mind, a bad oxygen sensor can be temporarily fixed or circumvented. However, if your oxygen sensors are acting up, fixing them as soon as possible is advisable. Not only will you keep your share of hazardous gasses within the mandated requirements, but you’ll also avoid risking further damage to the emissions control system and the engine. A temporary fix for a bad o2 sensor should be exactly that – temporary. Below are the necessary steps to temporarily fix the bad oxygen sensors.

Determine which oxygen sensors require replacing.

Modern cars typically have several oxygen sensors placed along their exhaust system, including one in front of the catalytic converter on the exhaust manifold (upstream O2 sensor) and one after the catalytic converter (downstream O2 sensor).

The easiest way to determine the malfunctioning sensor is to pull a fault code using an OBD2 scanner by connecting it to your car’s computer. Alternatively, you can let a professional do it in their repair store.

Prepare the car

If you’ve opted for a DIY route, the next step is to prepare the car for the broken oxygen sensor replacement. You’ll have to disconnect the negative battery terminal and jack up the vehicle so that you can safely reach its undercarriage.

Disconnect and remove the faulty oxygen sensor.

Although most modern vehicles will have their oxygen sensors on both sides of the catalytic converter, some models might house them inside. Once you’ve found the malfunctioning O2 sensor and its plastic plug, press the small tab on the plastic plug with one hand and pull it with the other to separate it from the sensor.

Now it’s time to unscrew the O2 sensor using a ratchet wrench. Note that you might need to use penetrating oil to loosen the sensor. Unscrew the sensor by turning the wrench counterclockwise and removing it from its power socket.

Install a dummy sensor.

Since a temporary fix for a bad o2 sensor requires bypassing the sensor by installing a dummy, now it’s time to reverse the process with a dummy sensor. This should take care of that pesky check engine light for you. However, the real issues will remain, and the longer you avoid replacing your bad O2 sensor, the worse it will get. Not to mention that, depending on where you live, using a dummy sensor might be illegal.

Alternatively, you could also try to clean your faulty O2 sensor to squeeze some extra miles from it.

Conclusion – Temporary Fix For Bad O2 Sensor

Temporarily fixing a bad oxygen sensor can be an option if you don’t have the money or time for an O2 sensor replacement. You can try rejuvenating the old O2 sensor or installing a dummy sensor to circumvent the issue momentarily, but neither is a sound long-term solution. Replacing faulty oxygen sensors is what all car owners should do sooner rather than later.

FAQ

Can I drive with a bad oxygen sensor?

You can drive a car with a bad O2 sensor, but that doesn’t mean you should. A bad O2 sensor can force your car to consume too much fuel, send wrong information to the catalytic converter, and hinder it from regulating hazardous gases properly. Aside from poor fuel economy and toxic gases, you also risk serious damage to the engine if you leave faulty O2 sensors unattended for too long.

How long can you drive with a bad o2 sensor?

Technically, for as long as your car lets you run it that way. Driving with bad oxygen sensors for longer than a few days isn’t advisable until you sort out a replacement. A temporary fix for bad O2 sensors is temporary, after all.

What happens when the oxygen sensor goes bad?

As explained above, a bad O2 sensor can lead to numerous issues that could destabilize your car. The most notable problems are poor fuel efficiency, loss of engine power, black exhaust fumes and rotten egg smell from the tailpipe, rough engine idle, misfires and stalls, failed emission tests, and potential damage to the catalytic converter and engine to name a few.

How do I know if I have a bad O2 sensor or catalytic converter?

A rotten egg-like sulfur smell is the most telltale sign of a failing O2 sensor or catalytic convertor. When one of these two components fails, your car will fail to regulate the exhaust gases properly and emit more sulfur dioxide than allowed.

Will a bad O2 sensor cause sputtering?

A malfunctioning O2 sensor won’t properly regulate the air-fuel mixture, which could lead to a rich or lean mixture in the combustion chamber. In the case of a lean mixture, the engine will have to deal with a higher proportion of oxygen in the fuel, making it harder to create combustion and leading to sputtering. You’ll also notice a drop in fuel economy.

How long do O2 sensors last?

An O2 sensor typically requires replacement after 100,000 miles in newer or 50,000 miles in older cars. Of course, like any component, oxygen sensors are known to give out earlier than that.

How much does it cost to replace an oxygen sensor?

An O2 replacement cost varies depending on the car’s make and model and the sensor’s quality. The most affordable sensors start from around $20, while the more expensive ones can save you a few hundred dollars. Factor in labor costs or the number of sensors needing replacement, and you’ll get your price.

Luckily, a skilled mechanic typically needs around half an hour on average to replace oxygen sensors. If they haven’t caused any damage to the converter or the engine itself, that is. Otherwise, repair costs will quickly mount, and you’ll wish you had replaced your faulty O2 sensors at the earliest opportunity.