Last Updated on March 4, 2021
The fuel injectors are the parts of the engine which are responsible for spraying fuel into the intake valves of the engine from where the mixture goes into the piston cylinders for the combustion. The ECU (engine control unit) determines the amount of fuel which is pushed into the fuel injector.
Why Fuel Injectors Get Clogged Up
Over time, fuel injectors slowly get clogged by the wax-like residue from fuel which is formed when engine is turned off and there is no fuel or gas to wash it away.
This buildup of the residue may be small at the time, but the continuous buildup of this residue could cause major problems for the car’s engine and for you, in the future.
Combine that with carbon deposits and other tiny debris, and you get less fuel injected than normal and in an unnatural spray pattern. Since an engine is so reliant on a proper air/fuel mixture, this can cause all sorts of problems.
Try This First
If you catch the problem early enough, using a good fuel injector cleaner (which is simply added to your fuel tank) once or twice is often enough to clear out any blockages in the injector and fix the issues at hand. This is usually the best first thing to try.
However, in many cases, a fuel system cleaner/additive is simply not strong enough for very dirty injectors since it’s being diluted with all the gas in the fuel tank. This is where a more involved fuel injector cleaning is necessary.
See Also: Symptoms of Bad Fuel Injectors
How to Manually Clean Fuel Injectors
What You’ll Need
- Fuel Injector Cleaning Kit (example: this or this)
- Aerosol fuel injector cleaner (example: this or this)
Note: Cleaning your fuel injectors is not a difficult task but it requires removing the individual fuel injectors from the fuel rail. We recommend a good service manual specific to your make and model to show how to remove and reinstall fuel injectors. If you don’t feel comfortable with this DIY process, there’s absolutely no shame in having a repair shop or dealership perform a professional fuel injector cleaning.
Fuel Injector Cleaning Procedure (Step-by-Step)
- Following the instructions in your service manual, remove the fuel injector.
- Choose the correct size plug that matches your size of fuel injector and connect it to the fuel injector.
- Choose one of the two white spray nozzles that matches the opening on your fuel injector and insert the fuel injector into the nozzle.
- Connect the black clip to the negative terminal on your car battery.
- Take off the spray nozzle from the aerosol can of fuel injector cleaner.
- Connect the top of the can to the adaptor nozzle of the cleaning kit.
- While pushing the adaptor nozzle down on top of the fuel injector cleaner can with one hand, use your other hand to touch the red clip to the top of the positive battery terminal to operate the fuel injector and allow the cleaning solution to spray out.
- DO NOT allow the injector to be energized for more than 1 second at a time. Instead, do 5 short touches of the red clip to the battery. With each spray, the spray pattern should start to change as the injector gets cleaned out.
- Once the injector has a nice clean spray pattern, disconnect it and repeat the other fuel injectors.
- Once all injectors have been cleaned out, reinstall them in the fuel rail according to instructions in your service manual.
Here’s a good video detailing the procedure above: