Comprehensive Guide: How to Clean Fuel Injectors

Although the fuel injector is small, it is a key component in the operation of the engine. The quality of gasoline atomization depends on it. Once a problem occurs, the vehicle's power performance will be significantly weakened, fuel consumption will increase, and the idle speed will become unstable.

Therefore, keeping the engine fuel injectors clean and unobstructed can help improve vehicle performance, reduce fuel consumption and extend service life.

What Are Fuel Injectors

The fuel injector is actually a simple solenoid valve. When the solenoid coil is energized, suction is generated, the needle valve is sucked up, and the injection hole opens. The fuel is ejected at high speed through the annular gap between the needle pin at the needle valve head and the injection hole, forming a mist, which is conducive to full combustion.

The injector is the most sophisticated component in an electronically controlled diesel engine. Its function is to atomize the fuel of more than 160 MPa and then inject it into the cylinder for combustion. A diesel engine rated at 1900 rpm has an average of 16 injection processes per second, and each injection process is divided into 3-5 small injections such as pre-injection and main injection, which places extremely stringent requirements on the response speed and control accuracy of the injector.

The fuel injector has extremely strict requirements on the cleanliness of the fuel. Water or impurities larger than 5 microns will damage it. Poor quality filters are difficult to intercept impurities and water in the fuel, causing many fuel injectors to be damaged. Many fuel injectors may not have seen what a damaged fuel injector looks like. Today I will dismantle a severely worn fuel injector to uncover it.

The Signs of Fuel Injector Need to Be Cleaned

The engine fuel injector is where carbon deposits are most likely to form. After a long time, it needs to be cleaned, otherwise it will affect the engine performance. So how do you judge whether the engine fuel injector needs to be cleaned?

Vehicle shaking

If you find that the vehicle is shaking seriously at idle speed, it may be because the fuel injector channel is clogged. Also look at the performance of the vehicle when starting. If the body shakes obviously in the first gear, but the shaking disappears as the gear gradually increases and the speed increases, it is very likely that there are a small amount of impurities on the surface of the fuel injector. In this case, it is recommended to clean the fuel injector, and the cleaning is not difficult.

Changes in fuel consumption

If your daily driving habits remain unchanged, and you find that the fuel consumption has increased significantly, accompanied by a decrease in engine power, it may also be related to the blockage of the fuel injector. At this time, you can use the decoder to read the data stream to determine whether the injection amount is normal and then consider cleaning the fuel injector.

How to Check Fuel Injectors​

First, remove the solenoid valve at the top of the injector. The solenoid valve is used to control the injection of fuel, allowing the fuel to be injected into the cylinder at the correct time and at the correct flow rate.

This part is the valve assembly inside the injector. It is one of the most easily worn parts inside the injector and consists of the valve cap and valve stem. The two parts on the plate are valve stems.

Valve Stem

For easy comparison, we specially found a new valve stem for comparison. The left one is a worn valve stem, and the right one is a brand new one.

Valve Cap

Let's take a look at the valve cap. The pit on the valve cap is also one of the parts that is easily worn. There is a steel ball in the pit, and the solenoid valve controls the fuel injection through it. When the pit is worn inside, the steel ball will not close tightly, causing the injector to return more oil, which will cause the needle valve to close loosely.

Nozzle of Fuel Injector

This part is the nozzle of the fuel injector, and the fuel is sprayed into the cylinder from its head. In the entire fuel injector, its working environment is the worst, because it has to directly face the extreme working environment of high temperature and high pressure in the cylinder.

The top of the needle valve of the nozzle plays the role of sealing the fuel. When there is no need to spray fuel, it must be leak-free. It can be clearly seen from the photo that the top of the needle valve of this nozzle has been severely worn, which is likely to cause the injector to drip fuel during operation. The dripping of the injector will cause partial overheating of the piston and even cause perforation of the piston.

Finally, let's look at the nozzle holes of the fuel injector. They are used to spray fuel into the cylinder, and their diameter is very small, so small that it is almost invisible to the naked eye. The diameter of the hole is directly related to the amount of injection per unit time. If there are particulate impurities in the fuel, it will cause irreparable wear to the nozzle hole. Over time, the diameter of the nozzle hole will become larger and larger. The consequence of the larger nozzle hole is that the fuel supply will increase, resulting in torque exceeding the limit, black smoke, and high fuel consumption.

Obviously, the nozzle on the left has a much larger diameter than the new nozzle on the right, which means the nozzle on the left has been severely worn and cannot be used any more.

How to Clean Fuel Injectors

Non-disassembly cleaning

The most commonly used method now is to add the cleaning treatment liquid directly into the fuel tank in proportion, and circulate it with the fuel system to clean the fuel injector. This method is easy to operate and has a good effect on lighter fuel injector carbon deposits. It can also be used as a daily fuel supply system maintenance.

Idle cleaning

This method does not require the removal of the fuel injector. Just mix the cleaning fluid with gasoline and inject it into the storage bottle of the cleaning equipment, connect the special cleaning tool and the fuel supply pipe joint of the fuel nozzle, start the engine and keep idling until the cleaning fluid is exhausted and the cleaning is completed.

Hanging bottle

The traditional method is to first cut off the power supply of the fuel pump, disassemble the oil pipeline, inject the cleaning agent into the hanging bottle, connect the compressed air pipeline, start the engine and control the speed until the cleaning agent is used up. This method is more complicated to operate, but the cleaning effect is better.

Disassembly and cleaning

Also called ultrasonic cleaning, remove the fuel injector and put it into the ultrasonic cleaning machine, add an appropriate amount of cleaning agent, and use the energy generated by high-frequency oscillation to remove the carbon deposits and dirt inside the fuel injector. This method requires professional equipment and cleaning agents.

Where to Buy Fuel Injectors Replacement

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