Injector Care Guide

The car injector is a key component of the EFI engine. It works as a normally closed valve controlled by the ECU. When the ECU gives the injection command, the voltage signal causes current to flow through the injector coil, generating a magnetic field that lifts the valve needle and allows fuel to spray from the injection hole.

The biggest advantage of injection fuel supply is precise fuel supply control, which helps the engine maintain the correct air-fuel ratio in any state, keep running smoothly, and meet exhaust emission requirements.

Deposits and impact

Car injector carbon and impact

How Deposits Affect the Car Injector

As one of the key components of the EFI engine, the injector’s work seriously affects engine performance. Injector blockage can seriously affect car performance. The blockage comes from carbon deposits in the engine or impurities in the fuel that block the injector pathway.

After the car has been driven for a period of time, certain deposits form in the fuel system. The formation of deposits is directly related to the fuel of the car. First, gasoline itself contains gum, impurities, or dust brought in during storage and transportation, which accumulate over time to form deposits similar to sludge in the fuel tank, fuel inlet pipe, and other parts. Second, unstable components in gasoline react at certain temperatures to form gum and resin-like viscous substances. These sticky substances remain in the injector, intake valve, and other parts, and when burned, the deposits turn into hard carbon.

Urban traffic congestion also makes the car run at low speed and idle more often, which aggravates the formation and accumulation of these deposits. Fuel system deposits are harmful because they block the injector needle valve and valve hole, affect the precision parts of the electronic injection system, reduce power performance, cause intake valve carbon to affect closure, raise fuel consumption, worsen exhaust emissions, form hard carbon on the piston top and cylinder head, shorten the life of the three-way catalytic converter, and ultimately can seriously block the injector and damage the engine.

Cleaning interval

Cleaning car injectors

When Should You Clean the Injectors?

To clean the car injector regularly, but long-term non-cleaning or frequent cleaning can also cause bad effects. As for the cleaning interval, it depends on the condition of the car and the quality of fuel you usually add. In general, most users are recommended to clean around 20,000 to 30,000 km. Good vehicle condition and fuel quality can extend the interval to about 40,000 to 60,000 km.

When there is a slight clogging of the car injector, it can affect the car’s condition. Sometimes there may be a fault where the car shakes a little when you hang a gear and start, and the phenomenon disappears when you hang a high gear and accelerate. If the car’s various sensors work normally, the throttle valve has been cleaned, and the circuit is normal, it is likely that the injectors have a slight blockage.

When accelerating in high gear, the slight gum may be sprayed away again or dissolved, and the performance of the car is restored. Such a slight clogging of the injectors can generally be left without cleaning because the slight gum can be dissolved away. Therefore, in daily driving, you should often run a highway in order to reduce the possibility of carbon deposits.

If the gasoline quality is poor or the vehicle has been driven for a long time and the injectors are not cleaned for a long time, the blockage phenomenon will be more serious. This can cause poor engine injection, poor injection angle and atomization, idle or acceleration problems, power loss, rising fuel consumption, increased emissions, and even engine failure. Therefore, the car injector should be carefully cleaned and tested regularly to ensure that it works properly.

Injection principle

Cleaning car injectors

Injection Pressure and Control Basics

The same type of EFI car has a constant gasoline pump pressure. Regardless of throttle opening, as long as the fuel pressure regulator is adjusted, the pressure of the car injector is always constant. The fuel injection nozzle must work in strict coordination with the fuel pump and fuel pressure regulator to achieve the best atomization effect at the designed pressure.

If the pressure is lower than the design pressure, the sprayed oil is not foggy, is columnar, and is not suitable for mixing with air. If the pressure is too large, the sprayed oil becomes cone-shaped and is also not easy to mix, and the force of injection is too large, so a lot of fuel is sprayed directly to the wall of the pipe, directly affecting the mixing ratio parameters.

Whether it is acceleration or idling, the pressure should be constant. Different models also vary in pressure. The amount of oil injection depends on the length of the injection time. Injectors are divided into voltage-driven and current-driven types according to the different control methods of the solenoid coil.

Voltage type is also divided into low-resistance and high-resistance. High-resistance can be connected to 12 V electricity, while low-resistance can only be connected to low voltage. If low-resistance is wrongly connected to 12 V for a slightly longer time, the coil will burn. When injecting oil, the voltage provided by the computer is constant; for example, 12V immediately becomes 0V when the oil is cut off. The change is instantaneous. This is a pulsating DC signal, not AC power. When the injector is clogged, the oil injection is not smooth, or there is carbon and glue in the injector gap, the designed oil amount and atomization effect cannot be achieved, and only cleaning is needed.

Troubleshooting

Troubleshooting

Six Common Injector Faults

  1. Blockage of the spray hole.It can be unclogged through the needle, and the unclogging should be cleaned carefully. If the needle valve body large plane and the main plane of the car injector have poor contact, chromium oxide can be coated on the flat plate for “8” grinding. If the needle valve cylindrical surface wears larger, the needle valve coupling should be replaced in pairs.
  2. Poor sealing.The needle valve and needle valve body sealing are poor, resulting in poor atomization or dripping oil from the injection nozzle. Fine chrome oxide or toothpaste can be coated on the needle valve end of the seat, but not on the cylindrical part. Then insert the needle valve into the needle valve body while knocking and turning until tight. The abrasive stone must be washed away with chromium oxide or toothpaste.
  3. There is air in the oil circuit.Remove the air from the oil circuit.
  4. Oil supply is not normal.The oil delivery pump needs to be overhauled. If there is air leakage from the oil delivery pipe joint, try to connect it so that it does not leak.
  5. Insufficient elasticity.The piston spring has insufficient spring force or has broken, and the spring should be replaced.
  6. Piston wear.Piston wear affects oil supply, so the piston should be replaced.

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