Injection Issues: How To Spot And Clean Dirty Fuel Injectors

Your car's fuel delivery system relies on a fuel injector to introduce the right amount of gasoline into the engine for proper combustion. Unfortunately, these injectors can get dirty over time. When a fuel injector gets dirty, it can restrict how much fuel flows through. If your engine isn't getting the right amount of fuel, it won't run well. Here's a look at what you need to know to spot a dirty fuel injector and clean it out.

Signs of Dirty Fuel Injectors

The first step to keeping your car's fuel delivery system running at its best is knowing how to spot dirty fuel injectors. Here are a few symptoms to watch for.


When the engine doesn't get enough fuel, it will hesitate. The hesitation occurs most frequently under acceleration, because the engine needs added fuel flow to increase the power response for that acceleration.

Starting Trouble

Your car needs sufficient fuel to maintain an idle or to start when it's cold. If your car's giving you trouble either idling evenly or even starting from a cold state, your fuel injection system is likely the culprit.

Reduced Fuel Efficiency

When your engine isn't receiving the proper fuel flow, it can't use that fuel as efficiently as it otherwise would. This means that your car's fuel economy may suffer. If you notice a reduction in your fuel economy along with any other symptoms, it may mean your fuel injection needs a cleaning.

Cleaning the Fuel Injector

If your car's fuel injection is dirty, the best way to restore your engine performance is to clean it. With the right supplies, you can do it at home.

Gather Your Supplies

You'll need to have a long, flat-bladed screwdriver and a fuel injection cleaning kit to do the work yourself. You'll also need to know the recommended fuel pressure rating for your car. You can get this from the owner's manual or by talking with someone at a local auto parts store.

Cleaning the Injector

Disconnect the fuel pump, which is usually located near the gas tank. Install a U-hose on the end of the return line so that any fuel drawn out will be returned directly to the tank. This keeps any fuel from being introduced to the engine while you're cleaning.

Once the fuel pump has been disabled, you can disconnect the pressure regulator in the line as well. Then, attach the fuel injector cleaner to the cleaning port on the fuel rail. Once the cleaner is connected, unscrew the cap to your fuel tank. This prevents any unnecessary pressure from accumulating in the fuel system.

Open the fuel injector cleaner's valve until it reaches the fuel pressure rating recommended for your car. As soon as the pressure reading is correct, turn on the ignition. Let the engine run until the container holding the cleaning solvent is empty and the engine turns off.

When the engine turns off, disconnect the cleaner kit, install the pressure regulator, and tighten the gas cap. Remove the U-line from your fuel pump and turn it back on. Open the hood and start the engine. Place the tip of a screwdriver against the case of the fuel injector and rest your ear against the handle. Listen for a clicking noise. This noise indicates that the injector is clean and functioning as it should.

Knowing how to spot a problem with the fuel injection and fix it yourself can save you hundreds of dollars and hours at the repair shop. But, if this doesn't restore your engine response, you'll want to talk with a mechanic about inspecting and possibly replacing the fuel injectors like sr20det injectors.