How to Clean Fuel Injectors

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Unless you’re driving a very old car, odds are good that your vehicle has fuel injectors. This is a good thing because fuel injection improves power, fuel efficiency, and emissions compared to older technology like carburetors. It also has the benefit of being super reliable for many thousands of miles, and while it's rare to hear of a fuel injector breaking outright, they can and will get dirty if mistreated. Luckily, in all but the worst cases, fuel injectors can be cleaned by you at home with no tools or expertise necessary. Keep reading to learn how to clean fuel injectors.

How to tell if your fuel injectors need cleaning

The first step in cleaning your car’s fuel injectors is determining whether they need to be cleaned. What are signs of a clogged fuel injector? A few indicators of dirty injectors include reduced fuel economy, reduced vehicle performance, rough idle, hard starting or even engine misfires. If your vehicle has a lot of miles on it or you regularly put cheap gasoline in it, it’s probably a good idea to assume that it would benefit from some injector cleaning as well.

How to clean your fuel injectors at home

There are a few different levels of injector cleaning. The first and most common is to go to an auto parts store and buy a bottle of fuel injector cleaner. These products work by increasing the amount of solvents and detergents in your fuel to help dissolve deposits that may have built up in the tiny orifices at the tips of your injectors. By using these cleaners, you can often clean your fuel injectors without removing them.

Using these products is simple. First, read the instructions on the back of the bottle. There will typically be an amount of gasoline that is best to mix with the cleaner. If your bottle says that it treats up to 10 gallons but you have a 20-gallon tank, either wait until you have a half tank of fuel or put two bottles into a full tank. Then just drive your car until the fuel is very low to reduce dilution of the product in your tank and give it the best chance to work.

When choosing an injector cleaner, we recommend sticking with something like Chevron Techron or Liqui Moly Jectron because they have repeatedly proven to be effective cleaners and are available at most auto parts stores. What you don’t want to do is add things to your fuel that aren’t designed to work as injector cleaners. For example, adding brake cleaner to your gasoline would be a bad idea and could damage your fuel system.

If your injectors are really dirty or clogged

If you are experiencing severe symptoms of dirty fuel injectors, or you tried the above method and didn’t notice an improvement, the next step would be to take your vehicle to a dealer or mechanic and have your injectors cleaned. This is usually a two-stage process that involves stronger-than-retail solvent in your gas tank and another special solvent that is fed directly into your vehicle’s fuel rail that supplies the fuel injectors. The mechanic will then run your vehicle on the special solvent before reattaching your fuel supply line. They will then either have you drive the vehicle or they’ll take the vehicle out for a test drive to ensure that everything is clean and functioning as it should.

Special cases

In some special circumstances, such as with some diesel fuel injectors, older-style continuous injection injectors (Bosch CIS or K-Jetronic), or on vehicles with injectors that aren’t easy or cheap to find replacements for, a mechanic may opt to remove the injectors from your vehicle and clean them on the bench. There are special machines that use ultrasonic waves in a tank of solvent to free up stuck or dirty injectors. The mechanic can perform flow tests of those injectors before and after to make sure they’re all flowing the same amount of fuel, ensuring that your engine will run correctly.

How often should you clean your fuel injectors?

While cleaning your injectors with solvents like the ones we’ve discussed can be extremely beneficial for your car, doing it too often isn’t a great idea. Because these products contain some harsh chemicals, they may, over time, start to degrade plastic or rubber parts in your fuel system. Once a year is a good rule of thumb, or if you drive a lot, consider using them once every 5,000-10,000 miles, especially if you use cheap fuel.

How to avoid cleaning your injectors entirely

What if we told you that there is a way to seriously reduce the likelihood of you needing to clean your vehicle's injectors, and which would also ensure the rest of your fuel system stayed cleaner and worked better for longer, and all you had to do was put gas in your car? Well, there is, and it’s called Top Tier fuel.

Top Tier fuel sounds like a marketing gimmick, but in truth it's an agreed-upon set of standards among a handful of fuel companies that ensure a specific amount of detergents and other additives are present in your fuel above what is mandated by the Environmental Protection Agency. These detergents work by preventing the buildup of deposits and gunk in the first place and are often only slightly more expensive than fuel from non-Top Tier brands. Fuel stations selling Top Tier fuel will usually have branding at the pump so you can tell fairly quickly what you’re getting.