Why does the car smell like gasoline when it starts? What is the reason for the strong smell of gasoline in the car exhaust?

The main fuel burned in a car is gasoline, which is then converted into kinetic energy by the engine, so that the car can run normally. Many car owners smell a strong gasoline smell when starting their car. Why is this?

Why does the car smell like gasoline when it starts?

This has a lot to do with everyone's refueling habits. You may have had this experience: when refueling, you have to wait until the gun jumps or jumps several times before you stop. You add too much gas and you can see the liquid level at the refueling port.

If too much oil is added, the gasoline will directly enter the carbon canister, affecting the normal absorption of gasoline vapor, and the vapor will be discharged from the vent. If your car is in external circulation at this time, the gasoline smell will be more serious than usual. Under normal circumstances, the carbon canister can absorb gasoline vapor and then send it back to the cylinder for combustion. This can save energy and protect the environment.

Another situation is that the gasoline pipeline leaks. If this happens, the gasoline will enter the car through the air conditioning system and absorb some dust at the oil pipeline leak to form sludge. We can find the problem by strengthening inspections at ordinary times. Of course, if the carbon canister rubber pipe is aging, it will also cause gasoline leakage. In this case, you will smell gasoline at any time.

It is recommended that you regularly check the oil line, carbon canister rubber pipe and other places for leaks, and be careful not to overfill the tank.

Why does the car exhaust smell so strong?

There are two situations in which the engine exhaust has a gasoline smell. One is that the exhaust has a gasoline smell during cold start. This is because when the engine is cold started, the temperature of the three-way catalytic converter is low and has not reached the operating temperature. The engine does not burn completely under low temperature conditions, so some gasoline will be discharged through the exhaust gas. Therefore, it is normal to have a gasoline smell during cold start.

Another problem is the smell of gasoline when the car is hot. The main reason for this problem is that the engine mixture is too rich, causing the gasoline to be discharged without being completely burned, which will cause the smell of gasoline in the exhaust gas. Generally, the engine fault light will light up when this happens. At this time, you can check the spark plug, ignition coil, injector, spark plug or ignition coil failure may cause ignition failure, and poor atomization of the injector nozzle will also affect the formation of a uniform mixture in the cylinder, thereby affecting combustion.

Another possibility is that the three-way catalytic converter has failed. When the three-way catalytic converter fails or is damaged, the oxygen sensor will be seriously blocked and will no longer be able to purify the engine, resulting in a gasoline smell. The only solution is to replace it.

How to check the fault when there is gasoline smell when starting the car

After starting a cold car, a relatively rich mixture is needed to maintain stable combustion, and the three-way catalytic converter inside the exhaust pipe can only purify the exhaust gas at around 400 degrees, so when the car is not fully warmed up, the exhaust will definitely have a gasoline smell.

If you often smell gas or oil inside or outside the car before starting or after warming up the car, then there is a problem and you need to check for oil leaks, whether the fuel tank cap is tightly installed, whether there is a hairpin or foreign matter in the one-way valve inside the fuel tank cap, the working condition of the engine, and whether the activated carbon canister of the EVAP system is normal, etc. All of these need to be checked one by one after testing.