How To Clean Fuel Injectors

If you drive a car with an internal combustion engine, you must watch for signs of dirty and clogged fuel injectors. After all, to run cleanly and efficiently, your vehicle’s engine needs to burn a steady supply of fuel. Fortunately, learning how to clean fuel injectors is not difficult.

Understanding Fuel Injectors

Internal combustion engines need a precise mixture of fuel and air to function. Fuel injectors deliver fuel to your car’s combustion chamber. That is, they spray just enough fuel into the chamber for your engine to burn effectively. If an injector supplies too much or too little, it won’t run well or it won’t run at all. While there are a few reasons air-fuel mixture may be rich, clogged fuel injectors often cause lean mixtures.

To remove carbon and other types of buildup from your vehicle’s fuel injectors, you must use a high-quality injector cleaner. There are hundreds of cleaners on the market today. While there is a difference in fuel system cleaners, any cleaner that you use at 100% strength is apt to do a good job. Said another way, the cleaner you choose probably depends on both personal preference and brand loyalty.

Identifying Clogged Fuel Injectors

Clogged fuel injectors are likely to make your vehicle’s engine idle roughly or stall altogether. If carbon accumulates on the diffusing tip of your car’s fuel injectors, you may also burn more gas and get worse fuel economy. Fortunately, before you get to either point, your vehicle’s Check Engine Light will probably turn on.

As you probably know, fuel has detergent additives in it that attempt to prevent fuel injectors from clogging. Still, these do not always do the trick. On the contrary, gunk in the fuel supply may eventually cause a clog. Alternatively, rust from your vehicle’s gas tank or a bad fuel filter may contribute to clogged fuel injectors. Either way, you must know how to clean fuel injectors to keep your vehicle running optimally.

Cleaning Fuel Injectors With Removal

Arguably, the best way to clean fuel injectors is to remove them from your vehicle’s engine. This, of course, allows you to thoroughly remove gunk. Even though there are a few steps involved in this type of cleaning, the effort is usually worthwhile, especially if the fuel injectors haven’t been cleaned in years.

  1. First, remove the fuel injectors from your vehicle’s engine. Since each engine is different, The amount of disassembly will vary significantly. You’ll need to disconnect the fuel supply and remove the fuel rails, in most cases. Fortunately, your vehicle’s service manual likely provides in-depth instructions on the process. If not, consult an aftermarket maintenance manual.

  2. Next, remove the rubber o-ring from the fuel rail side of the injector. Generally, you cannot reuse fuel injector rings, so be sure you buy replacements before beginning the project. After you have removed the fuel injectors and the o-rings, attach a rubber hose to the opening using hose clamps. This ensures no cleaner spills during the cleaning process.

  3. You need some electricity to effectively clean fuel injectors. Therefore, you must connect one side of an electrical lead to the injectors. The other side, you connect to the positive terminal of your vehicle’s battery. Only connect this lead, though, when you are ready for a spark.

  4. To ensure you completely clean your fuel injectors, disconnect the rubber hose from the rail side and attach it to the outflow side. Then, allow the cleaner to flow through the injectors the opposite way. This is likely to remove any deposits or buildup that your rail-side cleaning missed.

  5. Finally, attach a new o-ring and re-insert the fuel injector.

After you have cleaned one injector, you are ready to move onto the others.

Cleaning Fuel Injectors Without Removal

If you want to know how to clean fuel injectors without removal from the engine, you have some options. You may use a gasoline additive that cleans fuel injectors. The problem with this approach, though, is twofold. First, these cleaners dilute into a full tank of gas, weakening their potency and effectiveness. Secondly, they also only flow through injectors in one direction, making them less effective at removing carbon and other types of buildup.

A better approach is to invest in a fuel injector cleaning kit. These kits come with a canister that holds cleaner and a hose that attaches to your vehicle’s fuel injectors. While the design of these kits varies, most have a lid that screws off the canister. After unscrewing the lid, pour fuel injector cleaner into the container. Next, hang the canister on the underside of the hood to ensure you have a steady flow of cleaner into your vehicle’s fuel injectors.

Then, screw the hose end onto the vehicle’s fuel rail at the test port. To locate the fuel rail, find the fuel injectors under your hood or read through your car’s owner’s manual. If these approaches do not do the trick, a quick online search can help you locate the fuel rail.

Next, you need to turn the fuel pump off. To do so, remove the fuse that controls it from the fuse box. This disables the fuel pump, allowing gravity to pull cleaner from the canister into the engine. If your cleaner kit operates on air power instead of gravity, you also must hook the kit up to an air supply, such as a compressor. Then, you must turn the pressure gauge to the correct setting, usually about 50 PSI.

Finally, start the vehicle’s engine. Note, though, after attaching the cleaning kit and removing the fuel pump fuse, the car may be a bit tough to start. When all the cleaner empties from the canister, you have successfully cleaned your car’s fuel injectors without removing them. Of course, you must remove the cleaning kit and re-insert the fuel pump fuse to finish the process.

As you may suspect, different cleaning kits may vary in their functionality. While these instructions should give you a general idea of how these kits work, you should read through the manufacturer’s instructions completely to be sure you do the job correctly.

Helpful Resources for Fuel Injectors

Keeping Your Vehicle Running Optimally

Whether you need to know how to clean fuel injectors by removing them or want to do the job without tearing apart your vehicle’s engine, having clean injectors is an effective way to keep your vehicle running right. However you choose to tackle the project, it is worth your time and effort.

Looking for a fuel injection cleaning kit, fuel system additives, new fuel injectors, or other maintenance and repair supplies? We’re here to help. Find what you need to get the job done at AutoZone or speak to an associate for helpful advice, no matter what vehicle or project you’re working on.

Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

FREE Loan-A-Tool® program requires returnable deposit. Please note that the tool that you receive after placing an online order may be in a used but operable condition due to the nature of the Loan-A-Tool® program.

Related Posts