How To Clean Fuel Injectors

If you just recently bought a used car, it’s not a bad idea to give it a thorough once over. One way to ensure that your car is running its best is to check on your fuel injectors. Before you buy new ones, learn how to clean fuel injectors and save yourself some money!


Fuel injectors are responsible for spraying gasoline (or diesel, depending on your vehicle) into the engine. They shoot the fuel into the engine as mist at high pressure. When they clog, it can have serious consequences for the performance of your vehicle, and even for your safety.

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You can use an additive to your fuel to help keep your fuel injectors from clogging, but that may not always do the trick. Over time there is still build up on the fuel injectors because the additive you’ve placed in your gas tank is now being diluted rather than directly applied to your fuel injectors. It’s a band-aid, not a real fix.

We suggest a concentrated clean to ensure that any particles that are inhibiting your fuel injectors are removed.


You will need fuel injector cleaner, new fuel injector o-rings, a rubber hose, hose clamps, electrical leads with clips, a drip pan, your car’s battery, gloves, and safety glasses.


First, locate the fuel injectors in your engine and remove them. Next, remove the o-ring from the in-flow side of the injector. This is is the fuel rail side of your injector.


Next, use your rubber hose to connect to the in-flow side of the fuel injector. Use a hose clamp to ensure there is no leaking.

You will then need to connect the electrical leads to your fuel injector. Connect the other side of the electrical leads to the car battery. Be sure the standard black wire is connected to the negative terminal and the red wire is connected to the positive terminal. The positive side should only be connected when you are ready to fire.

Grab your gloves and safety glasses for this next part. First, add your injector cleaner to the rubber hose and connect the power to your battery. Give the injector a few short sprays to flush the cleaning fluid through the fuel injector. This is the concentrated clean we discussed earlier.

Then, you will need to disconnect the electrical leads from the fuel injector. Next, remove the hose clamp and the hose. If you’d like a complete a reverse flow flush, too, put the tube on the out-flow end of the injector. You can then reconnect your power. This will cause the fuel injector to attempt to fire.

When this happens, gravity will flow the cleaner through in the opposite direction, which will help remove any deposits that were too large to flow downstream. This will give you a more thorough clean and is highly recommended.

After the reverse flow flush is done, slide on new 0-rings to your fuel injector. You can then reinstall it and repeat the process with your other fuel injectors.

You just learned how to clean fuel injectors!