# Car Running Rich – Why Does It Happen?

Are you experiencing some weird symptoms in your car like increased fuel consumption and problems with the overall performance of the vehicle? Then you might be having a car running rich problem. But you shouldn’t worry because we are going to help you out in solving this problem.

Having a problem like this can be really frustrating because it will hit your wallet instantly. The fuel economy of your vehicle will get worse and worse and with a single fuel tank, you will not be able to cover even half of the mileage that you have been able when your car was in perfect condition. Another problem with a car running rich is the possible damage to other components in the engine that could occur from this unnatural engine work.

That’s why you need to improve your troubleshooting skills. You need to learn all of the possibilities that are out there when it comes to this problem. And also the solutions for them. And for this, you will need to do a good reading in finding out how everything works and how everything is connected. Because the car is like a puzzle, you need to learn how to solve these puzzles called car problems. But we are going to help you out with your effort.

First, we are going to elaborate on the problem of a car running rich. Then we will learn all of the different symptoms and reasons why this problem happens in the first place. After this, we will move in diagnosing and solving the issue. Finally, we will cover the costs involved in this work. So, if you want to learn more, follow along.

## Car Running Rich?

Now before we dive into more complex topics, let’s first learn more about the problem of a car running rich. If you know about the problem you can move on to the symptoms and causes of the car running rich. If not, keep up with us for a bit. So, what does all this means in the first place when the car is running rich? Well, let me explain.

When the car is running rich it means that the fuel to air mixture is messed up. The engine basically dumps too much fuel and too little air into the engine. Resulting in poor engine work.

If you didn’t know, the proper fuel to air mixture should be 14.7:1. But what does this means? This means that for each gram of fuel, there should be 14.7 grams of oxygen inserted into the intake of the engine. If this fuel to air mixture is broken the engine will run either lean or rich.

Lean is when there is too much air and too little fuel, while the rich mixture that we cover in this article means that in this case, there is too much fuel and too little air.

There is basically a ton of fuel dumped into the cylinders and this fuel cannot completely burn because there is too little oxygen. Resulting in a car running rich and a number of symptoms that you will come across while driving a car with this problem.

Driving a car will not be pleasant by any means and you will have a lot of trouble with an engine running like this. So, we are going to cover that in the following chapters where we will elaborate on the symptoms and causes.

## Car Running Rich Symptoms

As we already got familiar with the problem of a car running rich. Let’s focus on the symptoms of this problem. You probably know that every problem that we face when it comes to cars has some sort of symptoms in which it is represented. It is up to us to learn how to read these symptoms and learn how to solve the problem based on this input. Nevertheless, let’s jump into the symptoms of a car running rich.

### 1. Check Engine Light

When it comes to a car running rich, the check engine light is probably one of the first symptoms that you will notice whenever it occurs. So, why is this the case?

Well, this is the case because the ECM that is adjusting the fuel to air mixture is starting to notice some irregularities. The O2 sensor namely is starting to develop some weird reading by this irregular combustion. So, if you diagnose the problem with an OBD2 scanner, you will highly likely notice some errors concerning the O2 sensor and the catalytic converter.

This is the cause because these components are mostly affected by the car running rich problem. So, you should note this. Now let’s move to the next symptom of a car running rich.

### 2. Strong Odor Of Gasoline

Another symptom of a car running rich is the strong odor of gasoline inside of the cabin. Whenever there is a problem like in this case with the car running rich, the odor of gasoline will be very notable.

The smell will be more frequent when the car is stationary and doesn’t move. This can be really toxic for everyone inside the car and when this happens this should definitely be a red alert for you.

So, you need to act accordingly and try to diagnose the issue as soon as possible. You don’t want to drive in a car like in this case. Now let’s move to the next symptom.

### 3. Poor Fuel Economy

The next symptom of a car running rich that we are going to cover is the poor fuel economy. When this problem happens in your car the fuel efficiency will drop significantly.

You will notice this because you will be a more frequent visitor at the gas station. The board computer will also remind you that you have a problem because if your average fuel consumption was 25 mpg, but now it will be 19 mpg and lower in some cases.

Driving like this will be detrimental, for both, your budget as well as the engine of the car. There will be a number of issues that will pop up whenever there is a problem like this. So, let this symptom of a car running rich help you in determining the problem. Now let’s move to the next symptom.

Another very common symptom of a car running rich is bad engine work. This symptom can be a bit confusing and difficult to explain because it involves a ton of different sub symptoms.

These symptoms might include, rough idle, stalling issues, engine misfires. The engine will simply be very unhappy and will want you to sort out the problem.

The misfires are the most common because the spark plugs will get fouled by this rich mixture. They will get all soaked with gas and this gasoline will stick to the electrode. Preventing the spark plug to deliver electricity. Resulting in frequent misfires and complete failure of the spark plug.

So, whenever the engine is not happy you should consider that maybe the car running rich is happening to you, unfortunately. Now let’s move to the next symptom concerning the car running rich problem.

### 5. High Emissions

The next symptom that we are going to discuss concerning the car running rich problem is the problem with emissions. So, why is this the case?

Well, this is the case because when the fuel doesn’t ignite well and is dumped into the exhaust directly, it will cause the car to pollute more.

If you go to the DMV to register the car, you might fail the emissions test with a car like this. The technician will tell you that your car is polluting too much and you need to address the problem and bring your car at a later date.

This is not always like this, but if you live in NY or California where rules are strict, you can expect this. So, beware of this symptom of a car running rich.

### 6. Clogged Catalytic Converter And Backfire

Another symptom of a car running rich that we will cover is the problem with the catalytic converter and the frequent backfire that you will experience when this happens on your car.

If you run your car with this type of mixture, you will clog up the catalytic converter after a couple of thousand miles. And these converters are really expensive. They could easily cost \$1,000+.

Whenever this happens and the fuel is dumped in the exhaust unburnt, you might also experience backfire and explosions. These are small explosions but are still something that you don’t want.

Like in the old Hollywood movies when the car started smoking and there were bangs from the exhaust pipe. You will be basically in the same situation. And you don’t want that. Now let’s cover the last symptom of a car running rich.

### 7. Fouled Spark Plugs

The last symptom of a car running rich that we will cover is the problem with the fouled spark plugs. The spark plugs will often get soaked in gasoline as we mentioned previously.

Then this gasoline will stick to the spark plugs and often prevent them from working properly. The electrode will be covered in a greasy mess that will, later on, result in poor ignition of the fuel.

Poor ignition of fuel in other words means this problem will occur. So, you need to be aware of this issue and check your spark plugs once in a while and see if they are working properly. This will help diagnose the issue much sooner. But more on that later after we cover the causes for this problem.

## Car Running Rich Causes

Now since we learned all the symptoms of a car running rich, we are able to go deeper into diagnosing and solving this issue. And by this, we mean learning the probable causes for this problem.

That’s right, everything happens because of something and so is the situation with the car running rich. So, what are the probable causes for this problem? Let’s elaborate in the following chapters. Later on, we will learn how to diagnose the issue as well. So, keep up with us.

### 1. Faulty MAP Or MAF Sensors

The first and most probable cause for this problem with the car running rich is the bad MAF or MAP sensor. Don’t let these abbreviations confuse you. Both of these sensors are measuring the gases that are pushed inside of the intake.

MAP sensors are positioned on the intake manifold while the MAF sensors are usually mounted on the intake hose before the throttle body.

MAP sensors are usually installed in older vehicles from the early 90s. MAF sensors are running most modern cars. So, if you have a newer car, you are probably having a MAF sensor.

Some cars though, that are turbocharged can include both of these sensors. Namely, turbocharged gas engines and turbo diesel engines.

The task of these sensors is to measure how much air was sucked into the intake so the computer to be able to adjust the fuel mixture. Sometimes these sensors fail and develop a number of issues. Most notably the car running rich problem. Now let’s move to the next probable cause.

### 2. Clogged Air Filter

A clogged air filter can also produce problems like the car running rich. Why is this the case? Well, this is the case because the air filter is allowing air to get inside of the engine.

If the air filter has obstructions then there will be more part fuel dumped by the injectors and less part air. So, you get the point, check your air filter first and make sure that it is working correctly.

### 3. Bad Throttle Body Position Sensor

The second probable cause for car running rich is the bad throttle body position sensor. This sensor is basically monitoring the work of the throttle body. It is sending the data to the ECM and the ECM adjusts the air to fuel mixture.

Sometimes though, this sensor or the throttle body itself can fail. When this sensor fails, you will notice symptoms like rough engine work and also bad fuel economy, and car running rich problems occurring. Now let’s move to the next probable cause.

### 4. Vacuum Leaks, EVAP Solenoid Issue, PCV Valve

In this category of causes for car running rich problem, we decided to name a few in order to save some time. The important thing is that all these issues like the vacuum leaks, the EVAP solenoid, and the PCV valve have something to do with the gases that flow inside of the intake to burn.

Whenever some of these components fail, there will be unmetered inside of the intake manifold, and car running rich problem will occur. These are also very frequent causes for this issue. So, check these components first whenever you jump in diagnosing the issue of a car running rich.

### 5. Broken O2 Sensor

A broken oxygen sensor can also cause the car running rich problem to happen on your car. Why is this the case?

Well, there are two O2 sensors, one before the catalytic converter and one after the catalytic converter. They are measuring the work of the engine and see how good the fuel is burning. If the O2 sensors are sending bad readings, it could confuse the ECM and make your car running rich problem happen. So, beware of the O2 sensors, they are notorious for breaking.

### 6. Broken Injector

A broken injector can also cause the car running rich problem to happen. But why? This is because the injectors are designed to spray the same amount of fuel the computer tells them.

Sometimes though, these injectors can leak fuel whenever there is no need to do so. This extra fuel will cause your engine to run rich and will cause a number of issues. So, if nothing works, you need to address the injectors and see how they work. Now let’s move to the other probable causes for the car running rich.

## Other Probable Causes

There are some other causes that can make this problem with the car running rich. In order to save some time we will list them briefly.

These are usually sensors that can greatly affect the performance of the vehicle. These sensors include the intake pressure sensor that is located inside of the MAF sensor, the coolant temperature sensor that is in charge of measuring the coolant temperature and telling the engine to dump more fuel until the engine gets up to operating temperature.

The fuel pressure regulator is the third and last in our big list of causes for the car running rich problem. Now let’s dive into diagnosing the problem.

## How To Diagnose The Problem Of Car Running Rich?

So, how you can diagnose a problem like a car running rich? It is very easy and straightforward. You read all of the symptoms that we noted and if some of them overlap with the problem you dive deeper.

If you strongly doubt that this problem happens to you because you are sensing a strong smell of gas, check engine light and other symptoms that we listed above. The simplest thing you can do to see if this is the problem is to pull off all of the spark plugs and place them in the same order that you removed them.

Inspect them thoroughly and see if these spark plugs are fouled by the gasoline. If they are, they should be sticky and covered with a greasy substance. In addition to this, they will smell of gasoline.

The average electrode should be clean with only small carbon deposits and that’s it. If the spark plugs are all fouled by gasoline you found your problem.

Then you need to go a step ahead and learn why the spark plugs have fouled. For this, you will need an OBD2 scanner tool to scan the car for codes. Then based on these codes that you will get you should go for the solution.

Some problems like sensors could require bench testing because you don’t want to replace a good sensor. These sensors sometimes cost hundreds of dollars. So, beware of this. Now let’s learn how you can fix the car running rich problem.

## How To Fix The Problem Of Car Running Rich?

As we mentioned above, fixing the car running rich problem can be a tricky thing to do. In order to do this right, you will need to improve your troubleshooting skills and learn how to bench test specific sensors.

For this, you will need an OBD2 scanner tool as well as some equipment like a multimeter to measure resistance and other properties for this job. Depending on the problem that you discovered based on the errors you should look for proper bench test solutions.

You will have to learn how to bench test an O2 sensor, injectors, MAF, or MAP sensors. All these things have a different way on which can be checked if they work or not. So, it’s up to you and the cause of this problem. If you are not experienced, you can take your car to a shop and let them fix the issue. This way you will save a lot of time and nerves.

And that is not a bad idea, to be honest. Since these things like the car running rich can be really tricky to diagnose correctly and require a bit of experience solving problems.

## Cost To Fix The Problem Of Running Rich?

So, what is the cost of fixing the problem of the car running rich? This greatly depends much on the problem itself.

In the worst case, it will cost you a few hundred dollars if you have to replace an O2 or a MAF sensor. Nothing too significant but still, it is a struggle to diagnose this problem correctly.

The cheapest things to replace would be the coolant temperature sensor, spark plugs, PCV valve, EVAP solenoid, or a vacuum line. These will cost you less than \$100 to sort them out.

## Running Rich: Need-to-Know Facts

1. Running rich is a term used to describe a condition where a car’s engine is receiving too much fuel, resulting in an inefficient combustion process.
2. Running rich can lead to higher fuel costs, a poorer driving experience, and a worse environmental impact.
3. Running lean, on the other hand, occurs when a car receives too much air and not enough fuel, which is also bad for the engine.
4. Ideally, an even distribution of fuel-to-air is necessary for a car to run properly, which is referred to as an even “stoichiometric ratio.”
5. The symptoms of running rich include a strong, pungent smell from the engine, higher fuel costs, dodgy idling, and ruined spark plugs.
6. Dashboard warnings, such as the check engine light, can also indicate a problem with the combustion process that leads to running rich.
7. A professional mechanic can diagnose the issue by running full diagnostics, cleaning the mass airflow sensor, changing faulty spark plugs, and replacing the catalytic converter if necessary.
8. Ignoring running rich can lead to long-term engine damage, as excessive carbon deposits form and clog up the catalytic converter.
9. Paying attention to your car’s symptoms and dashboard warnings can help you catch the issue early and prevent costly repairs down the line.
10. If the engine is completely broken, it may be better to scrap the car and purchase a new one rather than investing in expensive repairs.

## Conclusion To Car Running Rich

In this article, we have covered quite a bit when it comes to the problem with a car running rich. First, we elaborated on the problem and learned that running rich means that there is too much fuel and too little air in the fuel to air mixture.

Then we covered the symptoms of a car running rich and as we noted these include the strong smell of gas (might help to learn how to get rid of cigarette smell in car), check engine light, and poor engine work. Then we covered the most probable causes, which are the MAF or MAP sensors, O2 sensors, and more.

Lastly, we focused on diagnosing the problem and finding the right solution.