6 Bad Fuel Injector Symptoms And How To Avoid Them?

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If you don’t know by now that engines run on fuel and air. And there is a bunch of ways to get the fuel-air mix into the engine. Sometimes, it is the carburetor, but more often its fuel injection. An engine needs a perfect mix of fuel and oxygen to function efficiently. In this article we shall discuss what are fuel injectors, how do they work and what are bad fuel injector symptoms.

How Does A Fuel Injector Work?

Fuel injectors are engineered to deliver this mix to the cylinder to create an explosion that produces the most power and the least amount of dirty exhaust as possible. This ideal air-fuel ratio is 14.7: 1. That means for every one unit of fuel 14.7 equivalent units of air at sea level are needed to achieve complete combustion. This is referred to as the perfect stoichiometric air-fuel ratio.

Fuel injection has a number of benefits over carburetors which includes easier cold starts, better fuel efficiency, and more consistent transient throttle response. Fuel injectors also make sure that the amount of fuel being sent to the engine is consistent across all cylinders, preventing inconsistent fuel distribution and power delivery.

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Fuel injection is fed by the fuel rail, which sits atop the cylinder bay. Because of the pressure from the fuel pump, fuel gets forced in the injector from the fuel rail and through a small filter inside the injector. Inside the injector, the gas hangs out in the reserve. Then, when it comes a time, an electromagnetic coil pulls the plunger up, opening the pintle injector, spraying fuel out of the nozzle. This spray happens multiple times every second, and every spray’s an exact amount of fuel. The timings are controlled by an electrical signal from the car’s computer and it works in concert with a spark plug.

What Are The Symptoms Of A Bad Fuel Injector?

There are six signs that can prove that your car has a bad fuel injector. The signs are as follows:

1. Engine Shaking:

An engine shaking is the sign of misfire. You can use a scan tool to examine which cylinder is misfiring, usually, p 0301 p 0302 to p 0303 p 0304 and so on codes are triggered. Use a graphing tool to test each fuel injector and if you do not have it, you can also use annoyed light as a less expensive alternative. A screwdriver can also be used, probe each fuel injector with a screwdriver and you can feel the clicks through it.

2. Lack of Power:

Now, again when a cylinder is not firing properly, then there will be a lack of power at takeoff and high speed.

White Smoke: if white smoke is coming off the tailpipe which usually means the fuel injector is stuck open and is spraying more gas than it should. This will result in poor gas mileage and will trigger a rich code.

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3. Hard Start:

Usually, when one or more fuel injector has completely failed, the vehicle will have a hard time starting and stay running.

4. No Start:

When one or more fuel injectors stuck open, the excess fuel can foul out the spark plug. This can cause due to wet spark plugs.

5. Bad Catalytic Converter or Oxygen Sensor:

Usually when excess fuel is dumped into the exhaust system for a long period of time which can damage the oxygen sensor and catalytic converter.

For better and visual understanding refer to the video given below.

How To Avoid It?

You can avoid these above bad fuel injector symptoms by cleaning or maintaining the fuel injectors on a regular basis on your own. As vehicle age, a lot of times carbon builds up in both the engine and fuel injectors and makes you burn a lot more gas and get worse gas mileage.

fuel injector

The fuel injectors can get clogged up and end up using more gas it needs to. There is a tool called ‘Run Right’ which can be used to clean the injectors. Just unscrew the top of the tool and pour the cleaner inside it until it is full.

Then just hang the tool on the hood and screws the other end onto the fuel rail of the vehicle. It just screws right onto the fuel injection rail at the test port. Then you go to the fuse box and takes out the fuel pump relay to turn the fuel pump off, so the tool cannot supply the fuel to the engine.

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Then you hook the air supply up powers the tool. Then you turn the pressure gauge to make the pressure in the system be about five-pound or less than the normal operating pressure. Then you start the vehicle. You can see the cleaner going right into the fuel injection system. It is done when the cleaner is going out and the air is coming into place. Now cleaner has done its job. For more clear and more visual understanding, refer to the below video.


Above gives you the essential information regarding your bad fuel injector. You can check whether if your vehicle is having the symptoms of a bad fuel injector or not, and if yes you can then you have to replace it. And if not then clean it on a regular basis by just following the simple steps as mentioned in the above article. You can also watch videos related to bad fuel injector symptoms and how to clean it.

If you have any queries or problems regarding the above article, then you can let us know in our comment box.