Informational Guide

How To Clean Fuel Injectors

Once you know how to clean dirty fuel injectors, you can ensure the engine is running as it should. Learn how-to here.

The fuel injector of your car is responsible for delivering fuel to the cylinders. If it is clogged or dirty, it can require cleaning to work properly. We review how to clean fuel injectors and give you a detailed guide of step-by-step instructions. Once you know how to clean dirty fuel injectors, you can ensure the engine is running as it should.

Why do you need to know how to clean your fuel injectors? The fuel injector transports the gasoline or diesel coming from the fuel tank and delivers it to the cylinders, where it enters the engine. When a clog occurs, or when the injectors become dirty, the correct amount of fuel might not make it through, leading to performance issues.

By optimizing the fuel flow, the system can better figure out how much air is needed in the engine. Plus, making sure your engine is running at its best helps to increase fuel economy and power.

Different Types Of Fuel Injectors Explained

  • Single-point or throttle body injection 
    This was the first type of injection, replacing the carburetor with a single-point design. However, this system isn’t as advanced as the modern designs.
  • Port or multipoint fuel injection 
    In this system, there is an injector nozzle for every cylinder. They are located directly outside the intake port. Because it shoots the fuel at the intake port, almost all of the fuel gets into the cylinder. This design allows for a better fuel/air ratio.
  • Sequential fuel injection 
    Otherwise known as a timed injection, the multiple injectors spray fuel in groups or at the same time. This small adjustment allows for better emissions and efficiency.
  • Direct injection 
    This is the most modern type of fuel injection. It sprays the fuel directly into combustion chambers, bypassing the valves. You will find this most often in diesel engines, but it’s becoming more common in some gas-powered motors.

8 Symptoms Of A Bad Fuel Injector (Clogged Warning Signs)

How do you know if your fuel injectors are clogged? If you begin noticing these signs, you want to learn how to clean fuel injectors at home.

  • RPM drops below optimal/normal level – because the fuel ratio isn’t enough to keep the engine running properly.
  • Regular engine misfires – occurs when there isn’t enough fuel being sprayed into the cylinder.
  • Strong gasoline smell – if the injector breaks or cracks because of age, you will start to smell fuel. This issue will require a fuel injector replacement.
  • Excessive engine vibrations – basically, the engine hiccups through the cylinder that doesn’t fire right.
  • Leaking fuel from the top of the engine – when the injector breaks, it’s common to notice a leak on the fuel rail or outside of the injector body. Once fuel is leaking, you can no longer clean the injector but need a complete replacement.
  • The check engine light is on – while this diagnostic system can alert you to a fuel injector problem, it also signifies many other faults.
  • Poor fuel economy – whenever the engine isn’t getting the right amount of fuel, it will burn more gasoline.
  • Failed emissions test – emissions might rise as the fuel burns improperly.

How to Clean Fuel Injectors (Step by Step Guide)

If you want to learn how to clean clogged fuel injectors, there are several steps you can take. For the most part, you can choose a simple avenue to start, with no experience necessary. However, if the situation isn’t resolved easily, you might need the help of a mechanic.

Start with a fuel injector cleaner kit. You can purchase many high-quality products that are dumped right into the fuel tank. Make sure you purchase the right type for your engine and dilute it if required. For the best results, you want to have a nearly-empty tank of fuel.

Once the cleaner is added, you can fill up the tank with fuel. If this works well, you want to know how often to clean fuel injectors? Most manufacturers recommend doing it every 60,000 to 90,000 miles unless you notice a problem before then.

If that doesn’t work, you can use a fuel injection kit directly into the fuel rails. Each kit includes a fuel injector cleaner, plus a hose to attach directly to the fuel rail. The fluid will dissolve carbon deposits and help the engine run better. You will need to locate the fuel injectors and possibly remove a few parts, so it’s best to consult your vehicle’s service manual first or get help from a professional.

If you choose this method, follow these tips:

  1. 1
    Follow all instructions on the kit.
  2. 2
    Disconnect the fuel pump relay.
  3. 3
    Attach the air supply to the canister’s air port.
  4. 4
    Adjust the system pressure, usually slightly less than the normal fuel-rail pressure.
  5. 5
    Start the vehicle and allow the solution to flow through the fuel rail. This normally takes five to ten minutes.
  6. 6
    Release pressure and disconnect the air supply. Disconnect your hose from the fuel rail.

If that doesn’t work, you will need to move onto the bench fuel injector cleaning option. It isn’t easy to learn how to bench clean fuel injectors. Of course, this is a more complicated option because it involves the removal of the fuel injectors. Some new parts are replaced, and the system is cleaned properly. At home, you can do this with a fuel injector cleaner, while your mechanic will likely use more specialized tools.

Cleaning Fuel Injector Tips:

  • Always wear protective clothing and gloves.
  • Don’t do anything you aren’t comfortable with. Fuel is flammable.
  • If you store your vehicle, consider using a fuel stabilizer to avoid problems.
car engine

People Also Ask (FAQs)

Do fuel injector cleaners really work? Do they harm the engine?

You might know how to clean fuel injectors with Seafoam, but does it really work? As with other car additives, the injection cleaner is completely safe to use and even recommended to keep your vehicle running its best.

How much does it cost to clean fuel injectors?

If you are simply adding a container of cleaner to the fuel tank, you should be able to spend less than $25. However, if you need to go to a mechanic, you want to know upfront how much to clean fuel injectors.

Can I put a fuel injector cleaner in a half tank?

You can, but it’s recommended to start with a near-empty tank and add a full tank of fuel after adding the cleaner. If you can only fill the tank halfway, you might consider using half of the recommended amount of cleaner.

How often should you clean your fuel injectors?

It depends on your vehicle. Check the owner’s manual, but most vehicles will recommend somewhere between 30,000 and 90,000 miles, or if you start to notice performance issues.

What can you do to keep your fuel injectors clean?

The kind of fuel you purchase can make all the difference, as some are more contaminated than others. Additionally, it helps to clean out the fuel injectors at the first sign that something might not be right.

Is it better to clean or replace fuel injectors?

As you learn how to clean fuel injectors on a diesel or how to clean motorcycle fuel injectors yourself, you realize that cleaning the injectors on any vehicle is a simple process. Replacing the fuel injectors isn’t as simple and should only be done when necessary.


How much does it cost to clean fuel injectors? It all depends on what process you use, but we've shown you several options. Take action at the first sign of performance concerns, and you have the best chance of cleaning out the injectors on your own.