Cleaning Diesel Injectors - What you need to know

Fuel injectors that are clean and functioning properly are a key element to getting the best performance and fuel mileage from your diesel engine (and gas engine, too). Properly functioning fuel injectors will inject the fuel in an optimal atomized-mist that burns cleanly and gets the most out of the fuel.

Over time, deposits build up in the tips of fuel injectors, typically when there's fuel left in the injector tips after the engine is shut down, which cooks and turns into deposits that affect the nice, clean spray of the injector.

The Importance of Cleaning Diesel Injectors

If the fuel injectors have deposits, it's important to clean them to restore engine performance back to the way it was.  At a professional garage, they may use an ultrasonic machine to clean the injectors out. Those who have some mechanical skill can pull the injectors themselves, dissasemble them, and clean the parts in an acetone bath and wire brushes. You have to be careful using this approach, as it's easy to damage the parts of tips. And you have to know how to put them back together.

If you're not up to taking the injectors apart by hand, you can try periodic fuel injector cleaner applications, which clean the injectors through the addition of concentrated detergent packages delivered through the fuel.  One thing to keep in mind, though, is that sometimes the injectors are not dirty, they are worn. And no injector cleaner or fuel additive is going to be able to fix a worn injector. Short of taking the injectors to a mechanic shop for bench testing, how do you know if the injectors are worn? You can try using a chemical cleaner and see if the performance reverts back to the way it's supposed to. If it does not, it may be well worth taking the engine in to a professional who can address what is most likely to now be a mechanical issue.

As an aside, there are some references on the Internet to the practice of adding gasoline to diesel fuel in order to clean the injectors. This is a bad idea because gasoline has the potential to change the combustion qualities of diesel fuel and also to strip essentially lubricating films from diesel parts in areas like the common rail injection system. So we would never recommend doing that.

Other posts that you may be interested in:

• Diesel Fuel Additives: Top 5 Things You Never Knew You Didn't Know
• Diesel Fuel Problems: The Doctor Is In
• How to Winterize a Diesel Engine