Fuel Injector Cleaning

Shouldn’t allow them to stay dirty…

Using liquid cleaners as fuel additives is easy, that’s pretty clear. However, sometimes that’s not enough to get the job done. While going to a professional mechanic is always an option to get your injectors cleaned, it’s not the only one. For those of you who like to put in the effort yourself, there’s the choice of purchasing a cleaning kit to get the job done. However, it’s not something you just know how to do by default – so the question remains:

How to clean fuel injectors?


First off, there are a few different choices. You can either remove the injectors from the engine for a thorough hands on cleaning or you can use a specific cleaning kit that attaches to the injectors and the fuel system, and uses pressurized cleaning solvents to clean the entire injector system. And thirdly, you can simply take your car into service – although there are different choices here as-well.

Let’s discuss these methods a bit more:


1. Manual cleaning with the injectors removed – the DIY (do-it-yourself) method. – Most difficult, time consuming and often the least successful method.

Fuel Injector Cleaning

You have to remove the injectors and clean every nook and cranny

It is generally not recommended for beginners to disassemble engine parts. Even with guides, there is a risk of messing things up and causing more problems than get solved. In addition, without specific equipment, the cleaning procedures may not be sufficient to get the job done.

Often times the entire fuel system needs cleaning and in such cases, simply removing and cleaning the injectors will not be enough. Professional service shops use expensive equipment to pressure clean and later thoroughly test the injectors to be certain the cleaning has been successful. Without expensive equipment, a low-tech, hands on approach to fuel injector cleaning may not provide good results.

There are numerous problems one must check when cleaning injectors manually – things like current draw and cracks are the most obvious. Specifically, the following things need to be observed and tested:

  1. Leaking. Fuel injectors have individual components – pintles, balls and discs that must be properly sealed while under operating pressure to avoid leaking.
  2. Fuel volume. Injectors need to supply the right amount of fuel under operating pressure.
  3. Atomization. Fuel needs to be under high pressure and atomized properly to provide optimal combustion.
  4. Distribution. The spray pattern of the fuel mixture is extremely important to guarantee safe and efficient combustion.

It’s clear that in most cases, the person going for the DIY method will not have the equipment and skills to accurately observe and test these things.

I would not recommend the DIY method for novices as the chance for success is limited. Those with the equipment and skills to tackle this approach are probably well educated on the cleaning procedures and would not require a short online guide. However if you’re looking to go all the way, check out some of our recommendations for fuel injector cleaning machines.

2. Using a fuel injector cleaning kit. – Fairly easy to use and provides consistently beneficial results. You do need a compressed air supply however. 

  • Fuel Injector CleaningFirst off, you need to get your hands on a cleaning kit. Have a look at some of the popular products HERE. Make sure the kit is compatible with your engine (the manual and likely online support by the company should help with this) – at times you may need to purchase additional adapters or connectors.
  • Make sure you have the right cleaning solvent. Some kits recommend specific products, so it’s best to go with those. Fill the cleaning kit’s canister with the appropriate liquid.
  • Attach the kit to your engine’s fuel port that is usually located on the fuel rail. Consult your vehicle’s and/or cleaning kit’s manual for more information where the connections are located and how to attach the specific kit.
  • Disable your engine’s fuel pump (you can do this using the fuse box or disconnecting/removing the pump) and either connect the fuel return line or insert a U-tube to make sure the fuel is returned to the gas tank. Keep in mind that the fuel can be under pressure and care should be taken. Also, some vehicle CPU’s may show error codes if the pump is disabled/disconnected/removed, so you may have to clear the error codes later.
  • Disconnect the fuel pressure regulator. (as the kit will be providing pressure)
  • Turn the ignition to make sure the fuel pump is offline – the  engine shouldn’t turn over.
  • Open/remove the cap on your vehicle’s gas tank. This is a safety precaution to avoid excessive pressure build-up in the fuel system.
  • Attach the compressed air hose to the cleaning kit and adjust the pressure to suitable levels. Consult the cleaning kit and vehicle engine manuals to make sure proper pressure it used.
  • Start the car and let the cleaning kit use up all the cleaning solvent. This may take 5-15 minutes. The engine should shut off by itself once the liquid has been used up.
  • You can now reverse the steps and disconnect the kit and reconnect/activate the fuel pump and fuel pressure regulator.
  • After everything is back to normal, start the car and listen to abnormal noises. Drive for a short distance to rule out any issues. If you notice a problem, it is always a good idea to see a professional mechanic.

While this method doesn’t always work perfectly for one reason or another (the injectors may be too badly clogged or there might be other issues in the fuel system), this method of fuel injector cleaning does produce beneficial results very consistently. It is also a very cost effective method as the cleaning kit and solvents are fairly cheap products to purchase, compared to regular professional mechanic work.

3. Visiting a professional mechanic/repair shop for manual injector cleaning with professional tools. – Easiest and most effective method. Most time consuming and expensive.

Fuel Injector CleaningThere are a few different methods used to manually clean and check the injectors at a professional repair shop, however I won’t be going into this topic here. I would like to talk about that in-depth and make some specific procedure recommendations, and I think that deserves another post entirely.

Safe to say that professionals will get the job done most effectively and will also be able to test the injectors afterwards to guarantee success. However, as one can expect, you have to empty your wallet a little and relinquish your vehicle for some time. Both of which can be a nuisance. Professional fuel injector cleaning definitely has its ups and downs.


I hope this article has provided some valuable insight. Take care of that engine and good luck!

– Jack