How To Clean Fuel Injectors With Maintenance Tips

​When the fuel injectors of your car are clogged or too dirty, they will ultimately harm the performance of your vehicle. Not only that, but they may also start using more fuel than normal which damages your wallet and may eventually start having all sorts of issues including stalling, power losses, and more.

Luckily, you can always do maintenance to your injectors and clean them to prevent any issue related to the lack of care. Whether it is because they are dirty, clogged, or just faulty due to lack of maintenance – here we are going to help you fix that. Take a look further into this article to learn how!

Why it is Important to Clean Fuel Injectors?

Fuel injectors have the purpose of injecting fuel to the combustion engine. They do this with extreme precision, so the engine works correctly with the right amount of fuel. This is all done thanks to an electrical coil and a nozzle that sense fuel and send it through sprays to the engine.

All this fuel goes to the combustion chamber which eventually creates the ignition for the vehicle to start and run.

What happens with fuel injectors is that a lot of fuel goes through them when the car is on. And of course, fuel creates build-up either by impurities in the liquid or by combustion residues.

These impurities and residues eventually clog the nozzles of the injectors, which could not only reduce the passing of fuel to the engine but sometimes even prevent it altogether.

This is why it’s vital to keep injectors clean. When they are clogged, the car will hesitate to start and run, you may begin to hear sputtering, misfires, and other weird noises from the hood too.

But when they are clean, the engine of the vehicle will run as usual, free of any sound or weird performance issue. So, it’s essential to clean them consistently to keep your car in pristine state.

What Are Injector Cleaning Kits?

If you are in search of a way to clean your fuel injectors, many people will tell you to go to a professional mechanic. But that can be time-consuming and costly. Instead, you can clean your own vehicle’s injectors by using a cleaning kit.

Yes, one of these kits is one of the best ways you can clean injectors without having to waste much of your money while saving some time. These kits come with everything you need to do an overall cleaning and keep your car working pristinely.

What’s important, however, is for the kit to come with the canister of cleaning liquid, a hose for injecting the cleaner, and a gauge to measure fuel pressure when cleaning. With all this, using a fuel injector kit is a piece of cake.

What Injector Cleaning Kit to Buy?

There are different types of injector cleaning kits to buy. Some of them are universal, which means you can use them for a wide array of cars with a generic fuel-injector and fuel rail constructions. Using them is a piece of cake, no matter what car model you have.

Other types of cleaning kits, however, will come with specific uses for selected cars. This could be due to a wide array of things, so it is important to always go for a kit that focuses on your car brand or model so you can prevent any issue when cleaning the injectors.

The real critical part when looking for the right injector cleaning kit is effectiveness, items, and formula. Some will clean better than others, some will be more expensive than others, and of course, some will come with tools and some will not.

Here we list what you should look for:

  • There’s a potent formula that cleans injectors the best: polyetheramine (PEA). It dissolves carbon residues faster & more effectively than other formulas.
  • Another formula to go for is polyisobutene (PIB). It doesn’t clean residues from carbon but helps to prevent the creation of new ones. This is less expensive than PEA formula and works as a great deposit inhibitor.
  • Some cleaners come with polyisobutylene amine (PIBA). This is a version of PIB that not only prevents the creation of build-up but also cleans. However, it is less effective and acts slower than PEA formulas.
  • All kits for cleaning injectors should come with a hose, a gauge, and the cleaning fluid. Sometimes, however, you may have to find each item separately.

How to Do On-Car Fuel Injector Cleaning Without Removing? 

Cleaning the injectors of your car without getting any part out of the vehicle is possible. It’s actually the simplest way to do it, without damaging any part. The only problem is that you’ll need a special tool to do it, yet it’s entirely possible once you have it.

What you’ll need is an air compressor or any other similar product to get the cleaner of injectors into the fuel rail so it can do its work.

But before doing any of this, you’ll have to follow a comprehensive list of steps so you can prevent damaging the car and do a more effective & deep clean of the injectors.

Finding the Fuel Injectors

Before doing anything, you should know precisely where the injectors are. To do this, we recommend taking a look at the vehicle’s manual or having the aid of someone who knows your car.

When you are sure where the injectors are, you can follow by searching for the fuel pump relay, the fuel pump, the fuel rail, the pressure vacuum line, and the fuel cap which will be necessary with the next steps.

Let Pressure Off the Engine

Start the vehicle and disconnect the fuel pump fuse or relay. This will make the engine drop fuel tank pressure in the engine in a matter of minutes.

Eventually, you will have to check the engine with the gauge and make sure the fuel pressure is at the lowest level. Now, you’ll be able to crack open the fuel line without having fuel spitting around.

Disconnecting Fuel Pump from Injectors

Now that you have lowered down the pressure in the engine, it is time to detach the injectors from the pump. You can do this by removing the fuel pump in the side of the engine and then pulling out the injectors.

Remember to read the instruction’s manual of the car to know how to remove these injectors without damaging them.

After removing the injectors, you can connect the fuel return line to the pump. This way any gas inside the pump goes back to the tank. You may also use a U-tube to get the fuel back to the tank.

Disconnecting Pressure Vacuum Line (If Needed)

It is important to know where the pressure vacuum line and regulator are inside the vehicle. Then you can take the vacuum line out without touching the regulator. The regulator is typically located behind the injectors, so be careful when removing the vacuum line.

Remember to read the instruction’s manual of the car. Some cars may not need the pressure vacuum line to be removed before cleaning the injector. Make sure what type is yours.

Attach the Cleaning Kit to Fuel Port

Now that you’ve removed the pressure vacuum line, you can connect the hose of the cleaning kit to the fuel port. The kit will come with tips on how to do this. Some fuel ports are different than others, but all of them are of similar size.

Try to fit the hose as tight as possible to the fuel port to prevent a leak or slippage. Then you can let the liquid go in.

While doing this, you should be careful of any fuel around the injectors. Only attach the hose after depleting the injectors and the fuel rail off the remaining gas. The cleaning liquid is flammable, so it’s critical to prevent any contact with fuel.

Start the Car

Now that you have shut the pump off and you have filled the fuel rail with the cleaning liquid, you can start the car. Starting the car will help the fluid to run through the injectors and clean them.

Eventually, once the injectors are filled with the fluid, the motor will stall by itself.

Don’t accelerate or push the engine in any way. Let the cleaner pass through the injectors while the car is in idle. It will shut off the engine after 5 to 10 minutes when the cleaner does its work.

Remove the Injector Cleaning Kit & Turn the Vehicle On

After the car shuts itself off with the cleaning liquid, it’s time to remove the liquid and reattach everything. The liquid will be totally used up after some time, which means you won’t have to get rid of many. Whatever stays behind, try to clear it up by starting the car again and let it burn.

If you don’t see any cleaner left, you can reattach everything including the fuel pump, gas supply, and so on. Check the fuel pressure gauge and make sure it is normal. Now, it’s time to start the car with everything put together to see how it responds to the injectors being cleaned.

It’s recommended to start the car and let it sit for 3-5 minutes after everything is reattached. Then you can take a quick drive of about 2 to 3 minutes to see how the vehicle responds. You should hear a regular engine working.

Otherwise, if you hear abnormal sounds, you may need to visit a mechanic.

Acceleration and power should also be normal. If you fire up the car and accelerate, but it doesn’t gain enough power, it is possible that the injectors were not cleaned entirely or that there’s an additional problem with the engine. Visit a mechanic if you experience a defective performance after cleaning the injectors. 

Considerations for On-Car Fuel Injector Cleaning

While cleaning the fuel injectors of your without removing them can be easy, it’s important to consider a few things before doing it.

Rethink About the Process

The steps for on-car cleaning fuel injectors are mostly for standard EFI systems. Gasoline direct injection or GDI systems run at different pressures so they will need different tools and processes to clean.

You will have to work in a ventilated area, use highly protective gear, and more. Unless you know what you’re doing, it’s always better to hire a professional for GDI system cleaning.

Injector Issue

If the injectors are too clogged or with too much build-up, they may not let the cleaner to pass through. It’s important to let them work correctly. Otherwise, you will probably end up with the same buildup on the injectors as before.

Additional Tests

After cleaning the injectors, some tests such as HC and CO with the emissions checker or an injector pressure drop test may be necessary. This will help you find out if the injectors are working better than before.

If you do these tests before and after to see the difference, it would be even better.

Correct Cleaner

Using strong cleaners with care is important. They can dissolve different types of materials including rubber, plastic, and thin metals with ease. Always avoid pouring the solvent or cleaner in the fuel lines, regulator or fuel pump.

Proper Protection

There’s a risk of fire while working with an injection cleaner and gasoline when running the car to clean the injectors. So you must always use non-flammable protective gear including glasses, gloves, boots, and gown or coat if needed. This way you can prevent injuries.

Following these considerations, it’s critical for proper cleaning of the injectors and avoidance of accidents to be prepared beforehand.

How to Do Off-Car Fuel Injector Cleaning

We know cleaning the injectors without removing them can be easy, but it also can be ineffective. When you have injectors that have too much build-up or just don’t get clean enough after using an injector cleaning kit – you’ll need to do off-car cleaning.

You’ll be using the same cleaning liquid or solvent to get rid of build-up alongside other tools. However, we recommend only doing this if you have enough experience. You may eventually damage the injectors that work well or damage the engine by not cleaning them correctly.

If you are willing to do it by yourself, here’s what you should do:

Drain Fuel Pressure

After cooling down for at least an hour, you can start this process. You’ll have to drain all the pressure in the fuel line first. You’ll have to disconnect the fuel pump, of course, and let the engine run until it starts to sputter and lose all the pressure it has.

Remove Fuel Rail & Injectors

After the engine is off because it doesn’t have any fuel or pressure inside, it’s time to remove the fuel rail and the injectors. For the rail, you’ll have to be careful with the regulator, and that’s it. However, when it comes to the injectors you will have to do it according to the car’s manual.

Remember to make sure where the injectors are located precisely. Some cars will have them accessible first-hand, while others won’t let you access the injector unless you remove many other things first, including tubes, cases, and so on.

Clean the Injectors

You’ll have to clean each injector individually. Using the cleaning liquid and a soft-bristle brush will be helpful to clean the outside. For the ones that look too bad or too clogged, you’ll have to replace them.

Only buy the ideal injectors for your car. Otherwise, you may eventually have unusable injectors in your engine.

While cleaning injectors doesn’t take much time or effort individually, it’s important to be careful not to damage them.

If you find an injector that’s faulty, it’s recommended to change all the injector set. Otherwise, you may eventually have an engine working unevenly.

Clean the Fuel Rail

Cleaning the fuel rail will not be easy, but you can do it with the same cleaning liquid or carburetor cleaner. To do it, you will have to spray the solvent through the holes of the injectors in the rail and slowly let the product do its work.

After 10 minutes, you can use an air compressor (with the fuel rail disconnected) to get rid of the dissolved buildup inside.

Reinstall the Injectors

After buying new injectors or after cleaning the old ones, it’s time to install them back. Do this with care and remember not to harm the fuel rail. Also, be careful when injecting the new injectors into the fuel rail not to damage them.

After cleaning each injector, it’s important to get new O-rings. Then you can reconnect the fuel pump and rail and start the engine to test the car.

Consid​​​​erations for Off-Car Injector Cleaning

Cleaning your injectors this way may seem easier than doing it on-car, but in reality, it isn’t. Here are a few tips to know before doing it:

Cost Efficiency

Removing the injectors from the car requires special tools and equipment. However, if you are experienced enough to do it, you may save a lot of money from taking it to the mechanic.

What’s even better, you can save even more money by not buying new injectors which can cost a lot of money per set.

Double Checking

After finishing the cleaning and installation of each injector, you should always try the car before moving it. Every injector should be working correctly without making unusual sounds.

If you sense any abnormal sound, you’ll have to re-clean the injector by repeating the processes. After re-cleaning, the injector should perform well. Otherwise, you’ll have to replace it.

Replacement As A Whole

As said before, it’s always recommended to replace the whole set of injects instead of replacing just one.

Unless you are one-hundred-percent sure of what you’re doing or you pick the same type, model, and brand of injectors as the old ones already installed in the car, it’s always better to change all of them to prevent the engine from working unsteadily.

How to Keep Fuel Injectors Working Well

Cleaning your injectors is critical for the engine performance and maintenance. But doing cleaning only won’t give the injectors a long lifespan.

Instead, you can try several other ways that will give your engine injectors a better performance & operative life:

Use High-Quality Fuel

Top tier fuel is the cleanest and most effective option in the market. While it is one of the most expensive out there, it will keep the injectors clean and prevent combustion-related residues that stay in the fuel rail and onto the injectors.

If you have a sports car, a TOP TIER fuel (not related to octane level) will be the ideal one to keep the engine working flawlessly and with no injector problem.

Clean Fuel Injectors Every Six Months

While it’s recommended to clean injectors every 15,000 miles, you can also do it every 10,000 or 50,000 according to your needs. However, it all depends on how much use you do to the car and dirty is the fuel you use.

The good thing about cleaning the injectors if that you can do it alongside any other process such as cleaning the carburetor, changing oil, or replacing tires.

Replace Injectors When Needed

Each time you clean the injectors, it is essential to check how they work. If they start malfunctioning even after hard-cleaning, you’ll have to replace them. Never let a faulty injector keep working on your engine. Build-up inside one injector may eventually pass to another injector.

What’s even worse, your engine will start misfiring, stalling, or sometimes not even starting or worse.

Let a Professional Clean or Replace the Injectors

If you can’t clean the injectors every six months or year, it’s recommended to let a professional handle the process. While it is not as hard as other car processes, cleaning the injectors can be very time & energy consuming.

If you hire an experienced mechanic do this for you, several issues such as faulty, clogged and poorly cleaned injectors will be forgotten. Be sure to know prices before doing this.

Drive the Car Every Week

One thing that many people tend to overlook is that fuel sometimes creates buildup inside the tank, fuel rail, pump, and injectors if you don’t move the car enough.

With more than seven days, a parked car can start producing carbon deposits. We recommend driving the car as much as possible, at least once a week for 15 minutes to prevent fuel-related issues.


Following this guide and tips will give you everything you need to clean and take care of your car’s fuel injectors. Remember that if you are inexperienced or have little to no knowledge about a vehicle’s engine, it’s always better to call a professional.

Otherwise, either the on-car or off-car process will seem like a piece of cake for you – especially with our help.

Don’t let your car run with clogged or dirty fuel injectors again. This guide has everything you need to prevent that and more.

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