Fuel injectors, as their name implies, are responsible for getting fuel into the engine. Fuel injection systems either work via a throttle body containing as few as 2 injectors, or go straight into the port with one injector per cylinder. The injectors themselves spray gas into the combustion chamber like a spray bottle, allowing the gas to mix with air before ignition. The fuel is then ignited and the engine keeps on moving. If the injectors become dirty or clogged, the engine cannot run as smoothly.
Performing a fuel injection flush can remedy issues with power loss or misfiring, or can simply be done as a precautionary measure. The process involves flushing cleaning chemicals through the fuel injectors in the hopes of clearing out debris and ultimately improving fuel flow. This service has stirred up a bit of controversy, with some claiming that a fuel injection flush is not worth the effort. With the cost of fuel injector replacement being as substantial as it is, a service that can remedy fuel injection issues or at least assist in diagnosing an issue can be extremely useful.
How do fuel injectors get dirty?
Whenever an internal-combustion engine is powered down, the combustion chambers have leftover fuel/exhaust hanging around. While the engine cools, the vaporized gases settle on every surface in the combustion chamber including the fuel injector nozzle. Over time, this residue can reduce how much fuel the injector can deliver to the engine.
Residue and impurities in fuel cause the injectors to clog as well. This is less common if the gas is from a modern gas pump and the fuel filter is functioning properly. Corrosion in the fuel system can clog the injectors too.
Does your car need a fuel injection flush?
Believe it or not, a fuel injection flush is most often performed for diagnostic reasons. If flushing the injectors in a car that is experiencing fuel delivery problems yields no results, the mechanic can mostly rule out a problem with the fuel injectors. If your vehicle is having issues that may be related to the fuel injection system or if it is just starting to show its age and has noticeably lost power over time, a fuel injection flush would be beneficial.
As a repair type of service, a fuel injection flush is not very effective unless the problem is specifically debris in or around the fuel injectors. Once the injector is malfunctioning then it is likely too late. If the problem is more serious than just debris, then the injectors can be removed and cleaned much more thoroughly via ultrasound. This process is very similar to how jewelry is professionally cleaned. An added bonus of this is that the mechanic can test the fuel injectors individually before they are put back into the engine.
If the injectors are not working properly and there is nothing clogging them, then the problem injectors have to be completely replaced.
This article originally appeared on YourMechanic.com as How Does a Fuel Injection Flush Work? and was authored by Ian Swan.