The following are the correct operating steps and precautions for self-cleaning fuel injectors. There are two methods: non disassembly cleaning and disassembly cleaning. Non professionals are advised to prioritize the non disassembly method:
1、 No disassembly and cleaning (suitable for daily maintenance)
Operation steps
Preparation: Turn off the engine to cool down the vehicle, turn off electrical equipment, and ensure that the fuel level in the tank is below 1/4 (to facilitate dilution of cleaning agents).
Add cleaning agent: Pour the fuel system cleaning agent (such as 3M, BG brand) into the fuel tank in proportion (usually 1 bottle to 50-60 liters of fuel), and then fill it with fuel mixture.
Driving cleaning: Start the vehicle and idle for 2-3 minutes, then drive for more than 30 minutes (it is recommended to use flowing fuel to wash away carbon deposits on highways or suburban roads).
Follow up processing: If approaching the replacement cycle, replace the fuel filter element synchronously to avoid new impurities blocking the fuel injector.
precautions
Choose original or large brand cleaning agents to avoid corrosion of components by inferior products.
If there is unstable idle speed after cleaning, some models need to reset the throttle valve with a diagnostic instrument (not necessary).
2、 Disassemble and clean the fuel injector (requires manual dexterity)
Operation steps
Power off disassembly: Disconnect the negative terminal of the battery, remove the engine hood, find the fuel rail, release the fuel line buckle (use a cloth to absorb residual fuel, prevent open flames), and take out the fuel injector assembly (mark the position to avoid installation errors).
Cleaning and testing:
Spray carburetor cleaner externally to remove oil stains;
The ultrasonic cleaning machine is set to clean at 40-50 ℃ for 10-15 minutes (or soak for 30 minutes with a soft brush lightly brushing the nozzle);
Measure the resistance of the fuel injector with a multimeter (refer to the standard value in the instruction manual, such as Bosch about 12-16 Ω), and replace it if it is abnormal.
Reset installation: Replace all sealing rings, reinstall the fuel injector in its original position, tighten the screws (do not apply excessive force), restore the pipeline and circuit, and start checking for oil leakage and abnormal noise.
precautions
Safety first: Keep away from sources of fire, wear gloves during operation, and avoid contact of cleaning agents with the skin.
Precision protection: Do not poke the fuel injector with metal tools (with a hole diameter of only 0.1-0.3mm). Ensure good sealing during installation to prevent air leakage.
Timely stop loss: If there are still abnormalities after cleaning, it may be due to wear of the fuel injector or ECU failure, and professional testing is required.
3、 Taboos and Suggestions
Prohibited operation: It is not recommended to disassemble and wash high-pressure common rail systems (such as National VI models) and diesel fuel injectors (requiring professional pressure calibration) by oneself.
Avoid excessive use: When there are no symptoms such as unstable idling or sudden increase in fuel consumption, frequent cleaning is not necessary to avoid damaging the original factory seal.
Priority major: For those who are operating for the first time or have no experience, it is recommended to go to a repair shop, especially when it comes to circuits and fuel pipelines, caution should be exercised.
Summary: No disassembly and cleaning is convenient and safe, and disassembly and cleaning must be strictly operated according to the steps. If you are not familiar with the process, seek professional help first to avoid malfunctions caused by improper operation.
