Why does there be gas when the fuel tank cap is opened? How to solve the problem that the car has ga

After the fuel tank cap is opened, the reason for the gas is that gasoline is a highly volatile fuel, and it will accelerate volatilization after shaking in the car fuel tank, and a large amount of oil and gas will be generated.

Is there a deflation sound when you open the fuel tank cap? Mechanic: Mainly for this reason, don't be tricked by the 4S shop anymore!

It adds up to a lot, and to a great extent.

Reason]: Because gasoline is a highly volatile fuel, it will accelerate volatilization after shaking in the car fuel tank, and a large amount of oil and gas will be generated; At this time, when the fuel tank cap is opened, there will be a jet phenomenon, which is a normal phenomenon.

How to open the fuel cap of the car]:

In general, there are two buttons or switches that can be pulled on the lower left side of the driver's seat, one to open the trunk of the car and the other to open the fuel cap.

The owner only needs to gently pull the button when opening the fuel cap, and sometimes it is difficult to pull and may need to open the door to find its position.

Then the door of the fuel cap will pop open.

Then come to the front of the fuel tank cap, there is a tightening knob, which can be opened by turning the knob in a clockwise direction.

After filling the gas, turn the fuel cap back counterclockwise, and you can hear the sound of twisting and stuck.

Sometimes there will be an embarrassing situation that the fuel tank cap cannot be unscrewed, which is more troublesome, you can drive to the car dealer to let the professional help you repair it, or you can remove the seat from the inside of the car, and pry the fuel tank cap with a screwdriver from the direction of the trunk.

Precautions]:

First of all, analyze why there is a sound, in fact, it is mainly caused by the difference in pressure inside and outside the tank. Usually, the carbon canister in the fuel tank of the car has the effect of ventilation to balance the internal and external air pressure. When there is a problem with the canister, if the fuel tank cap does not have the effect of relieving the pressure, it will lead to a pressure imbalance.

In fact, the sound of gas usually appears in summer, because the temperature in summer is relatively high, gasoline will expand after heating, because the vehicle space is fixed, the oil and gas inside the seal will be pressurized, and the pressure inside is greater than the air pressure outside, so there will be a sound when the fuel tank is opened. Actually, the sound that appeared at this time was not a big problem.

If there is an inhalation sound when it is opened, it means that the pressure inside the tank is less than the pressure outside. In this case, it is very likely that the canister or solenoid valve is faulty. When the pressure inside the tank is less than the pressure outside, there are two possible hidden dangers.

When the pressure inside the fuel tank is less than the pressure outside, it may cause the fuel tank to deform, and if it is seriously deformed, it may not even be able to add oil. Second, when the pressure inside the oil tank is less than the pressure outside, and the outside is not ventilated, the oil pump will be pumped out all the time, which may cause the oil pump to be damaged over time.

If you have this sound when you open the fuel tank cap, you should open the fuel cap after driving for two days; After driving for a few days, when the tank runs out, if you use this sound every time, it can basically be judged to be negative pressure. If that's the case, then it's time to get it repaired.

Summary. Hello dear, the solution to the car to open the fuel tank cap is to clean the blockage of the carbon canister. Cause Analysis:

It is normal for a small amount of gas to come out when the fuel cap is opened. If there is a lot of bubbling gas, it may be that the carbon canister is clogged, and gasoline is a volatile substance, which will naturally produce steam, but under normal circumstances, it is not allowed to be discharged in the air and will cause pollution. As a result, automakers designed carbon canisters with activated carbon to adsorb gasoline vapor in the tank.

Once adsorbed to a certain extent, the engine control unit will put the adsorbed oil into the combustion chamber and burn it. However, once the canister is clogged by dust and mud, resulting in the inability to adsorb oil vapor, the internal pressure of the fuel tank is out of balance, and the phenomenon of gas when the fuel tank cover is opened will occur. "So there's a lot of bumping, and it's possible that the canister is clogged.

Solution: Clean the canister.

Hello. Hello dear, the solution to the car to open the fuel tank cap is to clean the blockage of the carbon canister. Cause Analysis:

It is normal for a small amount of gas to come out when the fuel cap is opened. If there is a lot of bubbling gas, it may be that the carbon canister is clogged, and gasoline is a volatile substance, which will naturally produce steam, but under normal circumstances, it is not allowed to be discharged in the air and will cause pollution. As a result, automakers designed carbon canisters with activated carbon to adsorb gasoline vapor in the tank.

Once adsorbed to a certain extent, the engine control unit will put the adsorbed oil into the combustion chamber and burn it. However, once the canister is clogged by dust and mud, resulting in the inability to adsorb oil vapor, the internal pressure of the fuel tank is out of balance, and the phenomenon of gas when the fuel tank cover is opened will occur. "So there's a lot of bumping, and it's possible that the canister is clogged.

Solution: Clean the canister.

Hello dear, are you a small amount of gas or a large amount of gas.

Large gases. But there are still carbon canisters and electronic hair changes.

Your solenoid valve has also been replaced, right?

Yes. What do you think you're going to do now?

What area are you in now, and whether the pressure difference is more severe.

If there is a pressure difference with the atmospheric environment: after opening the fuel tank, there is a pressure difference between the two spaces inside the fuel tank and the atmospheric environment, and the gaseous gasoline with higher pressure in the fuel tank will be sprayed, and the spray is not ordinary gas, but gaseous gasoline, which is a normal phenomenon.

Are you at high altitude.

1. Normal situation.

Gasoline is a highly volatile liquid, in the hot summer, the fuel tank is closed to the outside world under normal conditions, to prevent oil and gas from escaping, and the oil pump in the tank will also produce heat.

Both gases and liquids expand when heated, and gases expand at a greater rate than liquids, but the entire tank space is a confined space and the volume is fixed. Therefore, the gaseous gasoline sealed in the fuel tank creates a pressure that is greater than the outside atmospheric pressure. As soon as the tank is opened, the gaseous gasoline with high pressure in the tank is sprayed out.

2. The carbon canister is blocked.

In summer, the oil in the fuel tank is more prone to internal and external air pressure imbalance, and the sharp rise in temperature at this time makes the carbon canister unable to deal with the air pressure imbalance in time for a while, so it is easy to open the fuel tank cover and have a jet sound. At this time, you should check whether the canister is clogged! Whether the canister solenoid valve is working properly.

Hello, I have seen your inquiry, please wait for a moment and answer it for you immediately.

Hello, analysis based on your problem description. In this case, it is generally a carbon canister, which is prone to failure and poor exhaust. Under normal circumstances, our fuel tank is communicated to the outside world through a carbon canister.

Another way is to carry out secondary combustion through the solenoid valve of the carbon canister, through the exhaust gas inside. If you open the tank cap and the pressure inside is very high, it is recommended that you replace the canister. It is also necessary to check whether the canister solenoid valve cannot be opened normally.

If the canister solenoid valve is normally closed, the fitting also needs to be replaced.

Because gasoline is a volatile liquid. So when we open the oil cap, there will be a puff of air coming up. This is normal.

Whenever the car fuel tank cap is opened, there is gas because gasoline is volatile, and when the car is moving, gasoline shaking will produce oil and gas.

1.Volatilization of gasoline. Gasoline is a very volatile liquid.

When the liquid evaporates into a gas, its volume becomes larger, but the volume of the tank is fixed under the seal, so the pressure increases. When the tank is opened, there will be a pressure difference, and there will be gas. This is normal.

2.Thermal expansion. Because the oil pump in the tank generates heat when it works, and if the weather temperature is high, the air temperature in the tank will also rise.

Because of the principle of thermal expansion and cold contraction, the volume of liquid and gas in the fuel tank will increase, so it will also cause the internal pressure of the fuel tank to increase, and there will be gas when it is opened.

3.The inside of the fuel tank is under negative pressure. When the vehicle is moving, the solenoid valve of the canister opens to continuously absorb volatile gasoline vapors. When the vehicle is driving for a long time, the inside of the fuel tank will be in a negative pressure state, and the sound of deflation will be heard when the fuel tank is opened.

4.The ventilation duct is clogged. When the canister is clogged, the tank pressure will be abnormal, causing the tank cap to erupt. It is necessary to clean up the activated carbon and the dirt that has accumulated on the round carcanister.

If there is an inspiration sound, it means that the internal pressure of the fuel tank is lower than the external pressure, which may cause the fuel tank to deform. If it is not ventilated with the outside world for a long time, the oil pump will continue to pump out, and it will be damaged after a long time.

In this case, it is very likely that the canister or solenoid valve is faulty. When the pressure inside the fuel tank is less than the pressure outside, there may be two hidden dangers: it may cause the deformation of the fuel tank, the deformation is serious, and the oil may not even be added; If the outside is not ventilated, the oil pump will continue to pump out, which will cause damage to the oil pump over time.

If you open the fuel tank cap and there is an air spray, it is not necessarily that the car is faulty. If the car has its fuel cap open and there is gas often in the summer, then it is possible that it is normal.

Because gasoline is a highly volatile liquid, in the hot summer, the fuel tank is closed to the outside world under normal conditions to prevent oil and gas from escaping. The work of the oil pump in the tank also generates heat, and both gases and liquids expand when heated, and the expansion rate of gases is greater than that of liquids.

However, the entire tank space is sealed, and the space volume is fixed, so the gaseous gasoline sealed in the fuel tank produces pressure, which is greater than the outside atmospheric pressure. When we open the tank cap, the gaseous gasoline with high pressure in the tank is sprayed out.

In addition to this, there is also a reason why the canister is clogged. Also in summer, the oil in the tank is more likely to have internal and external air pressure imbalances, and the sharp rise in temperature makes the carbon canister unable to deal with the air pressure imbalance in time for a while, resulting in a jet sound when the fuel tank cap is opened.

In this case, you should check whether the canister is blocked and whether the solenoid valve of the canister is working properly. If the owner thinks that the fuel tank cap will affect the normal operation of the vehicle, he can go to the repair shop for maintenance, or report the problem to the technician during maintenance in the 4S shop.

Photo by Pacific Automobile Network Q&A).

What is the reason why the fuel tank cap is opened with gas It is normal for the car fuel tank cap to be opened with gas, as follows: 1. Gasoline in the fuel tank with the change of temperature and the movement of the vehicle, a certain amount of fuel vapor will be generated, so when the driver opens the fuel filler, the pressure will be released, this phenomenon is normal; 2. If you feel that the pressure is too high, you need to check whether the carbon canister is blocked and whether the solenoid valve of the carbon canister is working normally; 3. Because the gasoline vapor is normally stored in the carbon tank, if the gasoline vapor has nowhere to go, it is in the fuel tank, which will cause the pressure in the fuel tank to be high. @2019