What is a Fuel Injector? | Signs of Bad Fuel Injector

The fuel injection system plays a big role in the efficient working of the vehicle. The fuel injection system consists of a fuel pump, fuel rails, fuel injector, and fuel filter. These parts ensure the engine to receive the precise amount of the air and fuel mixture. They control the amount and timing of fuel entering the combustion chamber during the power stroke for optimal combustion and efficiency. This article explains the working of the fuel injector and the symptoms of a bad fuel injector.

What is Fuel Injector?

A fuel injector is a mechanical device that injects fuel into the engine. The fuel injector contains a spray nozzle that properly injects diesel or petrol into the combustion chamber for optimal efficiency and combustion.

fuel injector

Fuel injectors were introduced as an alternative to older carburetor systems because they help to improve fuel efficiency and reduce emission rates.

However, the fuel injector may produce different problems if not properly maintained.

If the injector is faulty, the fuel will not be injected into the engine all at once, or the intervals at which it must be injected will be changed. In any case, your car doesn’t work according to your requirements.

Working of Fuel Injector

A fuel injector is one of the most vital parts of the internal combustion engine. It ensures the proper supply of fuel to the combustion chamber. The vehicle engine utilizes air and fuel to generate power. A fuel injector works in the following way:

fuel injector working

Fir of all, the fuel pump takes fuel from the fuel tank and transfers it to the fuel injector through fuel lines. When the engine control unit senses the fuel requirements, it sends a signal to the fuel injector, and the injector injects fuel to the engine cylinder according to the requirements.

As the fuel is injected, the air is mixed with the fuel, and the combustion process of the air-fuel mixture takes place.

Symptoms of Dirty Fuel Injector

As the fuel injector is clogged or damaged, it produces one of the below-given symptoms:

  1. Rough Idling or Idle Noise
  2. Misfiring
  3. Engine Vibration
  4. Fuel Leaks
  5. Check Engine Light Turns On
  6. Fuel Odor
  7. Engine Surge
  8. Bad Fuel Economy
  9. Failed Emissions Test

1) Rough Idling or Idle Noise

The rough idling is one of the main symptoms of a dirty fuel injector. As the injector goes bad, your vehicle noise may change from quiet to an extreme level. The vehicle engine starts rough idling or idle noise due to dust accumulation on the injector nozzle.

The dust accumulation on the nozzle affects the amount of spray and fuel spray ability of the injector. The engine may also generate rough noise due to dirty air filters, spark plugs, head gaskets, or other parts.  

2) Misfiring

Dirty injectors can lead to engine misfiring. Due to this problem, the engine feels spattering. In other words, when the engine misfires, the vibration is transmitted to the car. This misfire occurs when the fuel injector doesn’t properly supply the air-fuel mixture to the engine combustion chamber.

3) Engine Vibration

The vibration of the vehicle engine is one of the common signs of a dirty or bad fuel injector. A bad injector can cause the corresponding cylinder not to fire. This means the engine will vibrate or belch after trying to complete each cycle without fuel while driving.

4) Fuel Leaks

If you smell a pungent and sharp fuel smell in the compartment of your vehicle, then you may have a fuel leak. This fuel may leak due to a damaged or worn fuel injector. The fuel may also leak due to a damaged head gasket, fuel pump, or fuel filter.

5) Check Engine Light Turns On

The illumination of the “Check Engine” light is one of the major signs of a bad fuel injector. The check engine light is located on the vehicle dashboard. This may illuminate due to other problems, but a damaged injector is one of them.  

Whenever the injector delivers less (and in some cases more) fuel than it needs, it can reduce engine efficiency and activate CEL. Use the OBD2 scanner to check the problem.  

6) Fuel Odor

This includes fuel leaks, but you can smell gas if the gas isn’t burning because it’s damaged or stuck to the injector. The fuel may also leak due to a damaged fuel line or sensor fault that is telling the engine control unit to inject more fuel than it needs.

In any case, the cause of the gasoline smell should be identified and addressed just before it becomes a serious safety issue.

7) Engine Surge

The engine is one of the most common signs of a dirty fuel injector. The engine surging occurs when the injector injects more fuel into the engine cylinder than its requirements. This engine surging highly slows down the speed of the engine. In such a situation, you will observe a clear change in engine speed under constant load instead of staying constant.

8) Bad Fuel Economy

A damaged or dirty fuel injector may also lead to poor fuel economy. This is because the ECU requests more fuel from the injector, but the combustor is not receiving more fuel. When the engine consumes less fuel, then your fuel economy reduces.

If your injector is damaged or clogged, fuel economy may deteriorate.

9) Failed Emissions Test

If the injection pattern of the fuel injection system changes and the injector injects too much or too little fuel into the combustion chamber, there is a chance that the vehicle will fail the emissions test.

The inefficient and improper injection of the fuel may increase the emission rate of the exhaust gases, and the catalytic converter will not work efficiently.

In a few situations, a fuel injector leak can overconcentrate the air-fuel mixture and ultimately burn out the catalytic converter.

Cleaning Cost of Fuel Injector

Fuel injectors don’t last forever, but there are a few tips through that you may extend their life as much as possible. Maximum manufacturers recommend that you should clean the injector every 30,000 miles or so. This will prevent the injector from clogging and injecting fuel into the cylinder.

How to clean fuel injector?

Follow the below-given steps to clean your fuel injector:

  1. Get prepared: Before starting the cleaning process, properly wear the required PPEs (such as gloves and safety glasses). 
  2. Locate your fuel injector: Locate the location of the injector. The different cars have various locations of the fuel injectors. Read the vehicle manufacturer’s instruction manual to easily find the location of the injector.
  3. Disconnect the fuel pump from the fuel injector: Now, find the fuel pump and disconnect its connection to the injector.
  4. Remove the pressure regulator: Check the vehicle manual to check whether you should perform this step or not. If necessary, just pull the pressure regulator and remove it from the injector. 
  5. Link the fuel port to the cleaning kit: Now locate the fuel port, and connect the cleaning kit. Follow the instruction of the kit to connect the port and hose. 
  6. Disconnect the fuel tank cap: Now, remove the fuel tank cap. This helps to stop the build-up of additional pressure.
  7. Turn on your car engine: Now, turn on your vehicle engine and wait for at least 4 to 11 minutes for an efficient result of the cleaning solution.
  8. Disconnect the cleaning kit: Now, remove the cleaning kit from the vehicle and reinstall the fuel pump and pressure regulator.
  9. Turn your car on: Now run the vehicle and check the result.

FAQ Section

What is the replacement cost of the fuel injector?

The replacement cost of a fuel injector depends on the area you live, labor cost, vehicle model, and type of brand. The average replacement cost of a new fuel injector is from $90 to $510. The fuel injector cost is from $60 to $310, while the labor cost is from $30 to 200$.

What are the signs of a bad fuel injector?

The signs of the bad fuel injector are given below:

  1. Failed emissions test
  2. Rough idling or idle noise
  3. Bad fuel economy
  4. Engine misfiring
  5. Engine surge
  6. Engine vibration
  7. Fuel leaks
  8. Fuel odor
  9. Check Engine Light Turns On

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