
Is an adsorber in a car a necessity or can it be removed?
Those car owners who are interested in the contents of the underhood space have probably noticed a small cylinder or box with wires and pipes leading to it. It is usually located closer to the left or right wing, sometimes near the tank. This is an adsorber - a device that collects excess gasoline vapors, preventing them from escaping into the atmosphere.
Actually, the device owes its appearance to the introduction of the environmental standard "Euro 2". In addition to protecting the environment, the adsorber does not allow fumes to penetrate into the cabin, and even saves fuel a little. So it is a necessary thing. Although some people get rid of it, but we will talk about this later. But let's start with the name.
The common word from which these terms are derived is sorbeo, which is Latin for "absorb." The second word means completely absorbing something. An example would be a sponge with water. Adsorption is a process in which one of the components is not absorbed, but deposited on the surface. This is what happens with gasoline vapors in the car.
Externally, it resembles a large can or box attached to the car body under the hood. Inside the container there is activated carbon, on which gasoline vapors settle. The main components of a modern adsorbing system:
✅ separator – collects fuel vapors and sends them to the tank
✅ gravity valve – prevents fuel from spilling out in case of rollover (for example, in case of an accident)
✅ the pressure sensor releases it in hot weather, preventing the tank from swelling
✅ filter - activated carbon (granules) in a can collects fuel
✅ electromagnetic switch-valve – directs steam to the desired location
In some cars, the elements of the adsorber may be located in different places. For example, sometimes the electromagnetic valve is located separately from the flask with carbon.
The adsorber can also be located near the gas tank. Photo: youtube.com
The system can also include pipes and wires connected via a separate connector. Let's consider the adsorber's operation in two versions.
In this case, the vapors rise upward and immediately enter the separator, where they successfully condense, separating with the air and returning to the tank. But not all of them - some of them penetrate through the hose into the adsorber and settle there on the granules of activated carbon. It is precisely this that prevents the vapors from breaking through into the atmosphere. And where do they go then?
As soon as the engine starts working, a vacuum is created in the line and the electromagnetic valve opens. Air enters the tank, which, mixing with the settled gasoline, forms an ignitable mixture.
Adsorber for cars VAZ 2108, 2109, 2110-2115, Niva, Gazelle. Average price: 931 rubles. Photo: market.yandex.ru
The so-called purge begins, forcing the vapors to pass into the intake manifold. The result is, albeit small, but fuel savings. At the same time, the carbon freed from it is again ready to accumulate vapors.
All electronics of a modern car, including its "brains", calculate the proportions of the mixture taking into account the accumulated vapors. If they do not go to the manifold, the power supply system begins to fail. Why? For example, the coal in the "can" after a long period of inactivity of the car can simply settle, turning into a hard lump. Gases and vapors will not be able to pass through it, the pressure will increase and air locks will form in the tubes.
Fuel will be supplied to the cylinders intermittently. The result will be floating idle speed, gas pedal failures during acceleration.
Unstable idle speed may be due to a faulty adsorber. Photo: youtube.com
You can tell that the adsorber is faulty by the lit "check" on the panel or the smell of gasoline in the cabin and under the hood. Other symptoms:
✅ loss of engine power by 10-15%
✅ after starting and pressing the gas sharply, the engine stalls, the car moves in jerks
✅ the device's arrow "dangles", showing the tank as empty and then full (due to excessive pressure)
✅ fuel consumption increases
✅ when cold, a knocking sound is heard under the hood, similar to the sounds made by the valves, but they are adjusted correctly
Another sign is a hissing or whistling sound that occurs when the tank cap is unscrewed.
First, inspect the body: if it is plastic, cracks may appear over the years. The clamps on the hoses may also be loose. As a result, there is a loss of sealing and the inability to collect gasoline vapors. This is clear from their smell, which appears when the hood is opened.
Hissing and whistling when unscrewing the cap may indicate a malfunction of the adsorber. Photo: youtube.com
Most often, the cause of the malfunction is the electromagnetic valve. To determine its condition, disconnect the tubes and connector, blow with your mouth or a pump. If there is no voltage, the valve will be closed, i.e. hermetically sealed. If you apply 12 volts (it is not necessary to observe the polarity), it will open, air will pass. A characteristic click will be heard.
This is what the adsorber electromagnetic valve looks like. Photo: youtube.com
You can also check the valve coil with a tester. Set it to ohmmeter mode and take measurements: the arrow should show a resistance of 10-30 Ohms. If you get other data, the valve needs to be replaced. You can determine whether the carbon has caked or not by simply shaking the removed adsorber. You should be able to hear the substance pouring out. At the same time, check the pipes: it is possible that they are clogged with carbon granules.
Possible if the device is collapsible. It is unlikely that most car owners will do this, so this section is designed for those who like to dig into the depths of the car! You can start with the separator, or rather, its filter, made of foam rubber. Wash the latter, for example, with brake cleaner. Next, you need to pour the coal onto a baking sheet and heat it in the oven.
Coal in the Ford Focus I adsorber. Photo: youtube.com
First heat the substance to 100°C, after an hour raise the temperature to 300°C. As soon as the smell disappears, finish the procedure. At the same time, clean the body and sealing rubbers. When disassembling, use a telephone filming so that all the parts are in their old places.
The arguments are standard, like: "Why do we need it? We used to do without it. It's an extra headache. The simpler the car, the more reliable..." etc. Of course, you can remove the device. If you do it correctly, there will be no consequences for the engine. What do you mean?
A fine filter (these were once used in carburetor cars) is put on the pipe going from the adsorber cylinder to the separator. This is done to prevent foreign particles from getting into the tank. Now gasoline vapors will go into the atmosphere. And the outlet hose is simply blocked, the housing is removed from the underhood space. And the last stage is reprogramming the "brains" of the car, otherwise Check will constantly burn.
Removing the adsorber will not take much time. Photo: youtube.com
However, after the "operation" has been carried out, some disadvantages may appear. Namely: it is possible that the smell of gasoline may appear in the cabin, especially in the heat, when the fumes intensify. The second disadvantage, which is least paid attention to, is environmental pollution, and, as a result, non-compliance with Euro 2 standards. Another disadvantage is that there will be no fuel savings. Even if it is a little, a few kilometers of mileage are sometimes not superfluous.
There are also advantages. This is additional space under the hood, faster search for the causes of the malfunction in case of unstable engine operation at idle speed - the adsorber can be immediately excluded. Well, and, in case of the latter's breakdown, you will not have to spend money on its purchase.
Actually, the device owes its appearance to the introduction of the environmental standard "Euro 2". In addition to protecting the environment, the adsorber does not allow fumes to penetrate into the cabin, and even saves fuel a little. So it is a necessary thing. Although some people get rid of it, but we will talk about this later. But let's start with the name.
Adsorber or absorber?
The common word from which these terms are derived is sorbeo, which is Latin for "absorb." The second word means completely absorbing something. An example would be a sponge with water. Adsorption is a process in which one of the components is not absorbed, but deposited on the surface. This is what happens with gasoline vapors in the car.
How the adsorber works
Externally, it resembles a large can or box attached to the car body under the hood. Inside the container there is activated carbon, on which gasoline vapors settle. The main components of a modern adsorbing system:
✅ separator – collects fuel vapors and sends them to the tank
✅ gravity valve – prevents fuel from spilling out in case of rollover (for example, in case of an accident)
✅ the pressure sensor releases it in hot weather, preventing the tank from swelling
✅ filter - activated carbon (granules) in a can collects fuel
✅ electromagnetic switch-valve – directs steam to the desired location
In some cars, the elements of the adsorber may be located in different places. For example, sometimes the electromagnetic valve is located separately from the flask with carbon.

The system can also include pipes and wires connected via a separate connector. Let's consider the adsorber's operation in two versions.
With the engine off
In this case, the vapors rise upward and immediately enter the separator, where they successfully condense, separating with the air and returning to the tank. But not all of them - some of them penetrate through the hose into the adsorber and settle there on the granules of activated carbon. It is precisely this that prevents the vapors from breaking through into the atmosphere. And where do they go then?
When the engine is running
As soon as the engine starts working, a vacuum is created in the line and the electromagnetic valve opens. Air enters the tank, which, mixing with the settled gasoline, forms an ignitable mixture.

The so-called purge begins, forcing the vapors to pass into the intake manifold. The result is, albeit small, but fuel savings. At the same time, the carbon freed from it is again ready to accumulate vapors.
What happens when the adsorber does not work
All electronics of a modern car, including its "brains", calculate the proportions of the mixture taking into account the accumulated vapors. If they do not go to the manifold, the power supply system begins to fail. Why? For example, the coal in the "can" after a long period of inactivity of the car can simply settle, turning into a hard lump. Gases and vapors will not be able to pass through it, the pressure will increase and air locks will form in the tubes.
To prevent the tank from swelling, there is a safety valve, however, it is triggered later, after malfunctions occur.
Fuel will be supplied to the cylinders intermittently. The result will be floating idle speed, gas pedal failures during acceleration.

You can tell that the adsorber is faulty by the lit "check" on the panel or the smell of gasoline in the cabin and under the hood. Other symptoms:
✅ loss of engine power by 10-15%
✅ after starting and pressing the gas sharply, the engine stalls, the car moves in jerks
✅ the device's arrow "dangles", showing the tank as empty and then full (due to excessive pressure)
✅ fuel consumption increases
✅ when cold, a knocking sound is heard under the hood, similar to the sounds made by the valves, but they are adjusted correctly
Another sign is a hissing or whistling sound that occurs when the tank cap is unscrewed.
How to check the adsorber
First, inspect the body: if it is plastic, cracks may appear over the years. The clamps on the hoses may also be loose. As a result, there is a loss of sealing and the inability to collect gasoline vapors. This is clear from their smell, which appears when the hood is opened.

Most often, the cause of the malfunction is the electromagnetic valve. To determine its condition, disconnect the tubes and connector, blow with your mouth or a pump. If there is no voltage, the valve will be closed, i.e. hermetically sealed. If you apply 12 volts (it is not necessary to observe the polarity), it will open, air will pass. A characteristic click will be heard.

You can also check the valve coil with a tester. Set it to ohmmeter mode and take measurements: the arrow should show a resistance of 10-30 Ohms. If you get other data, the valve needs to be replaced. You can determine whether the carbon has caked or not by simply shaking the removed adsorber. You should be able to hear the substance pouring out. At the same time, check the pipes: it is possible that they are clogged with carbon granules.
Cleaning the adsorber
Possible if the device is collapsible. It is unlikely that most car owners will do this, so this section is designed for those who like to dig into the depths of the car! You can start with the separator, or rather, its filter, made of foam rubber. Wash the latter, for example, with brake cleaner. Next, you need to pour the coal onto a baking sheet and heat it in the oven.

First heat the substance to 100°C, after an hour raise the temperature to 300°C. As soon as the smell disappears, finish the procedure. At the same time, clean the body and sealing rubbers. When disassembling, use a telephone filming so that all the parts are in their old places.
What if we remove the adsorber?
The arguments are standard, like: "Why do we need it? We used to do without it. It's an extra headache. The simpler the car, the more reliable..." etc. Of course, you can remove the device. If you do it correctly, there will be no consequences for the engine. What do you mean?
Removing the adsorber on the UAZ-Patriot
A fine filter (these were once used in carburetor cars) is put on the pipe going from the adsorber cylinder to the separator. This is done to prevent foreign particles from getting into the tank. Now gasoline vapors will go into the atmosphere. And the outlet hose is simply blocked, the housing is removed from the underhood space. And the last stage is reprogramming the "brains" of the car, otherwise Check will constantly burn.

However, after the "operation" has been carried out, some disadvantages may appear. Namely: it is possible that the smell of gasoline may appear in the cabin, especially in the heat, when the fumes intensify. The second disadvantage, which is least paid attention to, is environmental pollution, and, as a result, non-compliance with Euro 2 standards. Another disadvantage is that there will be no fuel savings. Even if it is a little, a few kilometers of mileage are sometimes not superfluous.
There are also advantages. This is additional space under the hood, faster search for the causes of the malfunction in case of unstable engine operation at idle speed - the adsorber can be immediately excluded. Well, and, in case of the latter's breakdown, you will not have to spend money on its purchase.
- Sergey Mileshkin
- youtube.com, VK Video, market.yandex.ru
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