How to Flush a Fuel Injector

The easiest way to distribute a liquid or vapor through any propulsion system is to ensure that the system is clean and free of obstructions. This applies especially to today's modern fuel systems, which distribute fuel and air mixtures into the cylinder head intake manifold by way of the fuel injector. When the fuel injectors are clean and free of blockages, the engine runs smoothly and efficiently. When they are dirty, it can significantly impact the operation of the entire engine. There are a few warning signs of clogged fuel injectors, including a reduction in fuel economy or engine power, or black smoke coming from the exhaust.

Method 1 of 2: Using fuel injector cleaning additives

Material Needed

Step 1: Purchase the fuel injector cleaning additive. Most of the time, DIY mechanics will start with this method to clean their fuel injectors if they begin to notice any of the common warning signs. The first step is to buy a small bottle of formula, enough for three to four gas tank fill ups.

If you choose to use it, the recommended dosage of Lucas Oil's Fuel Treatment is 2 to 3 ounces per 10 gallons of fuel.

Step 2: Pour the fuel treatment into the gas tank. Make sure to do this after filling the fuel tank. Add the recommended dosage after you determine how much fuel you added.

Keep it inside your vehicle to make sure you can add it with every fill up and on a consistent basis for best results.

Step 3: Continue this process for a minimum of three to four full tanks. The drawback of using fuel additives is that they are added in very small amounts so as to not negatively impact the performance of the vehicle or to trigger alerts caused by most fuel-related sensors.

It will take some time for them to work, but if done correctly, they should do a good job cleaning up the fuel injectors as well as the entire fuel system.

Method 2 of 2: Using fuel injector kits

Materials Needed

  • Fuel injector cleaner kit
  • Fuel injector cleaning solution
  • Hand tools for removing fuel lines, disconnecting the fuel pump or power to the fuel pump
  • Safety equipment including gloves and safety glasses
  • Scan tool

hanging the tool

Step 1: Hang the fuel injector cleaning tool from the hood. The system is air pressure applied but needs to be hung straight in order to work correctly.

pouring the cleaner

Step 2: Pour the fuel injector cleaner into the cleaner tool. The fuel injector cleaning liquid is comprised of special additives as well as gasoline.

When you attach this device to the fuel system, the engine will run on the liquid inside the device. Once the liquid runs out, the engine will shut down.

You need to always refer to the exact instructions that the product manufacturer supplies in order for this process to work correctly.

Step 3: Disconnect the fuel lines on the fuel rail. Most fuel injector cleaning tools have an attachment that connects the fuel line from the fuel pump to the unit, and an attachment from the unit back to the fuel rail.

If your system does not have this attachment, you'll have to disconnect the fuel line and disconnect power to the fuel pump so the unit does not supply fuel as the fuel injector cleaner is in use.

If your fuel injector cleaner has a connection to attach the fuel line to the unit, remove the fuel line from the rail and attach it to the unit. Then attach the fuel line from the unit back to the fuel rail.

If your fuel injector cleaner does not have this connection, you'll have to remove power to the fuel pump, remove the fuel line connection to the rail and then install the fuel line from the unit to the fuel rail.

Step 4: Run the cleaner through the fuel injectors. Connect the fuel line from the cleaning tool to the fuel rail. Start the engine with the fuel line open from the cleaner to the fuel rail.

Let the engine run until the tank on the fuel injector cleaner tool is empty. Disconnect the fuel line from the tool and reconnect the primary fuel supply line from the fuel pump to the fuel rail. Reattach power to the fuel pump (if you had to remove it earlier).

Step 5: Start the engine, check for error codes or clear existing codes. One of the drawbacks of using this system is that it tends to trigger sensors that monitor the fuel injection system.

If you complete this process, you'll need to have access to a digital scanner in order to clear these error codes.

If you've completed all of these steps and still can't find out the source of the problem, or need an extra set of professional hands to help fix it, contact YourMechanic to find a local ASE certified mechanic that will be happy to assist you. A diagnostic check will determine if you need to have the fuel injectors 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

Understanding Chevrolet Oil-Life Monitor (OLM) System and Lights
Car symbols, or dashboard lights, are a car service reminder. The Chevrolet Oil Light Monitor system indicates when and what service your car needs.
Understanding Hyundai Service Required Lights
Car symbols, or dashboard lights, are a car service reminder. The Hyundai Service Required light indicates when your car needs service.
Understanding the Plymouth Service Indicator Lights
Car symbols, or dashboard lights, are a car service reminder. The Plymouth service indicator lights indicate when and what service your car needs.

Related questions

Throttle position sensor reads 13% at idle and 75% fully open.
No, you can't start messing with those because there are all kinds of sensors. If you set that up in the throttle position sensor, it's going to get wrong reading, and may get the wrong amount of air and confuse...
My fuel level goes up and down. Is my fuel tank cap broken or what?
Hey there. This is likely related to the fuel level sending unit (https://www.yourmechanic.com/services/fuel-gauge-sender-replacement) inside your fuel tank. This is a unit that using a float system to measure the fuel level inside your fuel tank and relays this information to...
Do I need fuel injector flush
If you have never had the fuel injectors service or you are having problems that need the injectors flushed then it should be done. If you are not having any problems then running good fuel and additives in the fuel...

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