The gas station said the tank pressure was too high and asked to add additives.

Gas station staff prompt that fuel additives need to be added due to high tank pressure. This is usually related to abnormalities in the tank ventilation system or fuel evaporative emission control issues. The main reasons include clogging of the carbon canister, poor sealing of the fuel tank cap, increased fuel volatilization rate, carbon deposit accumulation in the oil circuit, false alarms from sensors, etc.

1. The carbon canister is clogged:

The activated carbon canister is the core component of the fuel evaporation control system and is used to absorb volatile oil vapor from the fuel tank. If it has not been replaced for a long time or is blocked by dust, it will cause the oil and gas to fail to circulate normally, causing an alarm to occur when the air pressure in the fuel tank increases. The status of the carbon canister needs to be checked regularly and replaced with new parts if necessary.

2. Fuel tank cap failure:

When the rubber sealing ring of the fuel tank cap is aged or the threads are worn, the sealing of the fuel tank will be destroyed, and external air will enter, causing abnormal air pressure. The performance is that obvious deflation sound can still be heard after tightening the fuel tank cap. Replacement of the original specification fuel tank cap can solve the problem.

3. Fuel volatilization intensifies:

During high temperatures in summer or during the use of ethanol gasoline, the fuel is more likely to vaporize and produce excess oil vapor. This situation is a normal physical phenomenon. Although adding fuel additives can temporarily alleviate it, it is recommended to choose a cool place when parking the vehicle.

4. Effects of carbon deposits in oil circuits:

Long-term short-distance driving can easily cause carbon deposition on the fuel injector, intake valve and other parts, which indirectly affects the fuel vapor recovery efficiency. The use of fuel additives containing polyetheramine can assist cleaning, but severe carbon deposits require professional, no-disassembly cleaning.

5. Sensor false alarm:

A faulty fuel tank pressure sensor or EVAP system wiring may trigger a false alarm. The symptom is that the engine fault light lights up frequently on the instrument panel, and a diagnostic tool needs to be used to read the specific fault code for maintenance.

During daily driving, it is recommended to regularly check the sealing of the fuel tank cap and replace the carbon canister every 20,000 kilometers.； Choosing regular gas station fuel can reduce the accumulation of impurities ； Before long-distance driving, you can add an appropriate amount of fuel system cleaner recommended by the original manufacturer. If air pressure warnings occur frequently and are accompanied by engine vibration and abnormally high fuel consumption, EVAP system leakage or carbon canister solenoid valve failure should be promptly investigated. Note that fuel additives are not a substitute for mechanical maintenance. For ongoing tank pressure problems, professional testing should be prioritized rather than relying on additives.