How to Clean Fuel Injectors

how to clean fuel injectors

Fuel delivery systems have evolved over the years and fuel injectors are now used in nearly every engine of modern vehicles, particularly those high-performance models. While this new technology upgrades engine performance, it also causes carbon build-up in the engine and fuel injectors. Knowing how to clean fuel injectors helps prevent cylinder misfires, bad fuel mileage, and other engine performance issues. 

Cleaning fuel injectors requires some mechanical skills because you need to remove them, clean them on a bench or table, and reinstall them. But don’t worry, because in this article, you will learn how to clean your fuel injectors without the hassle of removing them. Read on and make sure your engine performs optimally. 

Signs Your Fuel Injector Needs Cleaning

Fuel injectors are electronically controlled mechanical devices that inject the right amount of fuel into your engine. A faulty or dirty fuel injector may cause issues with the delivery of fuel into your engine. Cleaning may be needed when the following signs show up:

  • The engine is misfiring
  • Idling is rough
  • Dancing tachometer needle
  • Poor gas mileage
  • Dead engine

Tools You Need to Clean a Fuel Injector

The following are the basic tools needed for cleaning a fuel injector:

  • Wrench set
  • Air compressor 
  • Fuel system cleaner
  • Fuel-injector cleaner kit
  • New O-rings (optional)

The following are also needed to ensure your safety while cleaning:

  • Nitrile gloves
  • Mask or respirator (Filter fumes and odors)
  • Eye protection
  • Long-sleeved shirt (optional)

How to Clean Fuel Injectors

How do you clean fuel injectors? First, you need to prepare the necessary tools and follow the simple step-by-step guide below to be able clean the fuel injectors yourself:

How to Clean Fuel Injectors Without Removing Them

Cleaning fuel injectors can be done without removing them (On-car cleaning). Here are the steps on how to clean dirty fuel injectors: 

  1. Locate the fuel rail on the fuel injector. The fuel rail is one of the most important components of the fuel injector since it has the function of supplying the fuel injectors with fuel. Its location may vary between vehicles. To save time and effort, use your car’s manual to locate the fuel rail.
  1. Disconnect the fuel rail. Once you’ve successfully located the fuel rail on the fuel injectors, carefully disconnect it. There should be an exposed hose on which you can connect the fuel injector cleaning kit later on.
  1. Fill the fuel injector cleaning kit with a cleaning solution. Remove the cap of the fuel injector cleaning kit and pour in the cleaning solution. Make sure you fill the cleaning kit to the brim. 
  1. Attach the cleaning kit to the hood. The cleaning kit has to be above the engine. You should hang the cleaning kit on the hood to ensure it remains above the engine. There is a hook on the cleaning kit you can use for hanging.
  1. Connect the outlet pipe to the fuel rail. After the cleaning kit is hung, you need to attach its outlet pipe to the exposed fuel rail. The cleaning kit comes with several connectors. Install the one that fits your fuel rail and attach the cleaning kit. 
  1. Remove the fuel pump relay from the fuse box. Go to your fuse box and take out the fuel pump relay to turn it off. The fuel pump should not be supplying fuel to the engine while cleaning is ongoing. It’s best to refer to your car’s manual to know which relay is for the fuel pump as there are a lot of relays and they all look the same. 
  1. Connect the air compressor to the cleaning tool. Connect the air compressor to the air inlet of the cleaning kit and set it to around 40-50 PSI. The Air compressor uses air to push the cleaning fluid into the fuel rail. 
  1. Start your vehicle. Start your vehicle and keep it running until there’s no more cleaning fluid left in the cleaning kit. Once the cleaning kit is empty, turn off your vehicle and disconnect the cleaning kit. 
  1. Reinstall the fuel pump relay and fuel rail hose. Reinstall your fuel pump relay in the fuse box and reconnect your fuel rail hose back to the fuel injectors. Do this after your engine cools down so you won’t get burned. 
  1. You’re done. Congratulations! You now have clean fuel injectors. 

Removing and Cleaning Your Fuel Injectors

In case on-car cleaning doesn’t work, you can try removing them and cleaning them individually. Here’s how to do it:

  1. The first two steps are similar to that of the on-car fuel injector cleaning. Yow will need to locate the fuel rail and disconnect them. 
  1. Remove the fuel injectors. Once you’ve completed the previous two steps, you will need to remove the fuel rail and the fuel injectors. The removal of the fuel injectors will depend on the make and model of your vehicle. 
  1. Clean fuel injectors individually. After removing the fuel injectors, you can now clean them individually. Clean the outside of the fuel injectors using a soft-bristle brush and carburetor cleaner or electronic fuel injector (EFI) cleaner.
  1. Open the fuel injector. A fuel injector jumper can be used to energize fuel injectors to open them up. You can use a 9 V battery and wires to make a simple jumper. Using your fuel system cleaner, spray through the fuel injector from both directions.  
  1. Reinstall the fuel injectors. Once you’ve thoroughly cleaned your fuel injectors, you can now reinstall them with new O-rings, reconnect the fuel pump, and start the engine.  

How to Keep Your Fuel Injectors Clean

Keep your fuel injectors clean by doing the following:

  • Use top-tier detergent fuels. Or…
  • Use an in-tank injector cleaner every 5,000 miles.
  • Drive regularly

Frequently Asked Questions

A clogged fuel injector may show signs such as engine misfires, running very rough, poor fuel consumption, and causing bad emissions. 

If you follow the steps correctly, this procedure should take you about 30 minutes to 1 hour. 

It is recommended to get your fuel injectors cleaned every 60,000 to 90,000 miles to maintain ideal engine performance.

A simple fuel injector cleaning may cost you around $10 if you do it yourself. 


Every part of a vehicle needs to be kept in good condition to avoid any performance issues. Though cleaning fuel injectors is not part of regular maintenance, it is still necessary as fuel injectors get clogged up over time. The good part is, you already know how to clean clogged fuel injectors. So, keep your engine performing at a high level. And remember, the best way to clean fuel injectors is through the steps we discussed (which may also take practice).