How Does a Fuel Injection Flush Work?

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.


Next Step

Schedule Fuel Injector Replacement

The most popular service booked by readers of this article is Fuel Injector Replacement. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Fuel Injector Replacement reviews

Excellent Rating

(248)

Rating Summary
236
5
2
1
4
236
5
2
1
4

Robert

32 years of experience
646 reviews
Robert
32 years of experience
BMW 328i L6-3.0L - Fuel Injector - Mountain View, California
Robert brought the whole mechanic shop with his amazing knowledge/experience into my garage, and he was very flexible. He paid attention to every details during the repair process and didn’t bother to explain on my questions. Most importantly, Robert is a very honest man whom you can count on...^^
GMC K1500 Suburban - Fuel Injector - San Jose, California
I cannot begin to describe how great of a mechanic Robert is not only did he constantly keep me updated , was very straightforward , extremely professional and did absolutely excellent work we'll probably never use another mechanic other than him ever again I would recommend him to absolutely anybody

William

35 years of experience
731 reviews
William
35 years of experience
Cadillac STS V8-4.6L - Fuel Injector - Phoenix, Arizona
He came to the first appointment explained what was happening he was able fix and get me a quote for the issue I had and scheduled me quick for the other issue I had was able to explain with my certain items were not needed even though online portal stated was needed. Only paid for the services required to fix the issue. He kept in contact with me to advise on the repair status and the final result. Nice to have the mechanic come to you. Would recommend William very courteous.
Mercedes-Benz 380SL - Fuel Injector - Sun City, Arizona
William was wonderful. Very knowledgeable and hardworking. Absolutely the best of the best mechanic.

Torrieanto

13 years of experience
632 reviews
Torrieanto
13 years of experience
Chrysler Town & Country V6-4.0L - Fuel Injector - Saint Petersburg, Florida
Torreanto replaced all 6 injectors on my 2008 Town and Country for an extremely reasonable cost. He is a very competent mechanic with excellent experience. His troubleshooting and analytical skills were very apparent during our discussion of the work at hand. I really enjoyed talking with him on an engineer to engineer level. The job was completed in a timely manner with careful attention to detail. My car is running smoothly again with excellent power. He was also helpful in discussing other issues that were identified that may need addressing in the future. I will definitely look for him to do any necessary work on my van in the future.
Volkswagen Jetta - Fuel Injector - Riverview, Florida
Torrieantos arrived on time to complete the repairs. He was courteous, knowledgeable and got the car back up and running like new.

Jermaine

25 years of experience
382 reviews
Jermaine
25 years of experience
Saab 9-3 L4-2.0L Turbo - Fuel Injector - Silver Spring, Maryland
As always, the service I received was 5 star. I have never had a bad experience. It’s super convenient having your car fixed at home. No drop off. no waiting. rooms no missing work. I would highly recommend yourmechanic. Mechanics are always super friendly, fast and knowledgeable.

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Tune and Adjust Your Carburetor
While all modern cars use computer-controlled fuel distribution systems, there are still many vehicles on the road that employ the traditional carbureted method of...
How to Flush Your Power Steering System
Modern Modern cars are equipped with power steering (https://www.yourmechanic.com/article/how-does-power-steering-impact-a-vehicle-s-handling) which helps the driver easily steer the car by turning the wheel gently. Older cars do not have power steering and you had to use much more effort to turn the...
How to Replace a Fuel Pump Shut Off Switch
The fuel pump shut off switch may be faulty when the Check Engine Light comes on or if the engine suddenly turns off while driving.

Related questions

Car won't start after being parked
When the key is turned and nothing happens could mean several things; you have a bad battery (most common), the switch is bad, or the starter is not working. If you hear a click when you turn the key and...
Car won't maintain an idle.
Hi there. Try turning on the ignition to the ’ON’ position 3 times with 30 seconds each time to see if the fuel system had air in the rail. This will help with the air in the system. When starting,...
While driving my car will shut off if you start it again it will act like it's flooded for about 10 minutes then will start?
You should get the fuel pressure checked and the computer scanned. If running too rich then your fuel pressure may be too high or you have a leaking injector. A computer test will tell you if you have a sensor...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com