How can I Clean Fuel Injectors?

Eric Tallberg

The fuel injectors in today’s automobile engines are among the engine's most critical components. Keeping fuel injectors clean keeps the engine running at peak power and performance, saves gas, and cuts down on harmful exhaust emissions.

Fuel injection systems supply fuel directly to the cylinders of a vehicle's engine.
Fuel injection systems supply fuel directly to the cylinders of a vehicle's engine.

Fuel injectors are usually compromised by dirty fuel and fuel contaminated with water resulting in clogs and rust, respectively. You can clean fuel injectors using one of three different methods. The least effective method involves adding cleaner directly to the vehicle’s fuel tank. The wide variation in product quality and the inability to qualitatively measure effectiveness means that this method is, at best, a stop-gap measure.

Dirty or damaged fuel injectors may cause fault codes to be stored in the car's computer.
Dirty or damaged fuel injectors may cause fault codes to be stored in the car's computer.

The second method to clean fuel injectors is “on-car” injector cleaning. As this involves a fairly comprehensive mechanical knowledge, as well as working with pressurized, toxic and highly flammable materials, the on-car procedure for maintaining fuel injectors is not recommended for the faint of heart.

The last and most effective method for cleaning fuel injectors is to bring the vehicle to a mechanic with the proper knowledge and equipment for both cleaning and testing the fuel injection system. Most often, for less than $40 US Dollars per injector, the mechanic will remove the fuel injectors, clean the injectors “off-car” with an injector cleaning machine, and, using the same machine, test the injectors to ensure that they’re functioning properly. Should defects be found in the injectors themselves, the mechanic can replace the injectors. These new fuel injectors should be guaranteed, though this is a pricey alternative.

If you wish to try the on-car method to clean fuel injectors, various steps must be accomplished to ensure safe and effective results. With the engine off and no spark or open flame close by, disconnect the necessary fuel lines, making sure a container is properly placed to catch the fuel runoff from the lines. Next, either disconnect the fuel pump – which may lead to an fault code in the vehicle’s computer – or install a U tube to cycle fuel away from the engine and back into the tank while the cleaning process is being performed.

Wearing eye-protection, connect a pressurized container of cleaning solvent to the injectors. Avoid skin contact with the solvent. Start the engine and allow the solvent to flow into the injectors. When solvent has been properly fed into the injectors, shut off the engine. Remove the cleaning apparatus and reattach the fuel lines and the pump. Finally, take the vehicle for a test drive to determine the effectiveness of the cleaning and, if necessary, repeat the process to completely clean fuel injectors.

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Discussion Comments


@ Alchemy- If your dealer has been straight with you on all other services in the past, they were likely straight with you on this one, all though next time I would recommend paying a little more and having the injectors pulled so they can be back flushed and have the o-rings changed. I run an old Audi, and my friend has an ultrasonic cleaner so i clean my injectors myself. The difference in performance is definitely noticeable. If you have the patience and the skills DIY fuel injector cleaning is the way to go. You can also offer it as a service and make money on the side.


@ Alchemy- Injectors are probably the most overlooked part on a vehicle, but they are one of the most essential in modern engines. While on car cleaning is a temporary fix, off car cleaning is much more effective. You can tell if you need a cleaning if you are having hard starts hesitation on acceleration, sputtering on heavy acceleration, reduced gas mileage, or sluggish performance.

If you maintain your vehicle and use high quality gasoline with added fuel cleaners, you will likely need to clean your injectors far less often. You should have your injectors cleaned every thirty thousand miles or so, but if you normally run discount gas, you will likely need the service much sooner.


What is the best way to prevent the frequency of needing to clean my fuel injectors? Also, how do I know when to clean the fuel injectors in my vehicle? I was recently told I needed an injector service, even though I did not notice any sluggishness in how my vehicle ran.

Last time I brought my truck in for service I forked over a few hundred dollars for an injector cleaning. I am pretty sure it was an on-car injector cleaning service. I was a little disappointed after I got my truck back because I did not notice any difference. I felt like I should have seen some noticeable improvement in the way that my truck ran for that kind of money. The truck is always dealer maintained. Thanks to anyone who can give me a clue.

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