The gas tank of any car always contains vapors formed due to a decrease in atmospheric pressure or heating of the fuel. In order to prevent the leakage of fuel vapors into the vehicle, a special gasoline vapor recovery system (VPSU) is installed. Thanks to it, the vapors retained by the adsorber (essentially activated carbon) enter the intake manifold and burn in the engine cylinders. To regulate the amount of gasoline vapor coming from the adsorber to the manifold, a special solenoid valve is used.
Why do you need a gasoline vapor recovery system?
Injection vehicles (including Kalina), whose environmental class belongs to Euro-3, must be equipped with an EPS. This prevents fuel vapors from entering the atmosphere, polluting it. In addition, the system guarantees more stable operation of the power plant and saves gasoline. How to check the adsorber valve included in the SUBS and how it functions will be discussed further.
Principle of operation
The adsorber itself allows fuel vapors to accumulate in a special place - the separator. As a result, gasoline turns into condensate and goes back to the tank. Vapors that have not undergone treatment go through double valves of the system, one of which prevents fuel from spilling out during an emergency (for example, a coup), and the second “is engaged” in regulating the pressure in the tank. The adsorber purge valve is located under the hood, and the adsorber itself is located on the tank. The control unit ensures the normal operation of the entire system: it ventilates and removes condensation.
Design and operation of the adsorber purge valve
The KPA is an electromagnetic locking device that operates from the vehicle’s on-board network. The valve consists of:
- plastic case;
- valve with spring;
- windings;
- metal core;
- connector
When the vehicle's engine is turned off, no voltage is supplied to the valve and it remains in the closed position. That is, on the motor side, the system that captures vapors is blocked. At the same time, the adsorber begins to “collect” vapors. When the power unit starts, voltage is applied to the valve, causing it to open and fuel vapors to enter the intake manifold. As soon as the ignition is turned off, the control unit is de-energized and the pipeline is closed: no vapors enter the receiver.
Cars of a high price category have a more complex evaporation system. Such machines have special sensors that can “calculate” the amount of air and vapor as a percentage. This allows you to more accurately control the supply of gasoline to the injector.
How to disable or remove the adsorber on a car and do you need to reflash the ECU?
You need to understand that when the adsorber is removed, the solenoid valve is turned off, which is directly connected to the controller and controlled by the latter.
This will lead to error p0443, which we already mentioned above. The tubes are also silenced, in particular the one that goes to the intake manifold.
What is the disadvantage of such a shutdown?
The fact is that through the tube that goes to the intake manifold, air is constantly sucked in; even in idle mode, the so-called small purge of the adsorber occurs. At high speeds from 1500 – 2000 and above there is a lot of purging.
In the ECU firmware, constant air leaks and the flow of fuel vapor are taken into account when forming the air-fuel mixture, despite the fact that all this goes past the mass air flow sensor, the causes of the malfunction of which can be found out by clicking on the link.
If you plug the pipe, which many people do, a certain amount of air will not flow into the intake manifold bypassing the ECU, but the latter still takes them into account.
That is, the controller takes into account one volume of air, but another (smaller) one actually enters. As a result, the amount of fuel is generated by the ECU based on more air than is supplied. This leads to an over-enrichment of the air-fuel mixture.
As a result, the engine does not work correctly, because the mixture is constantly over-enriched where it is and is not needed, and fuel consumption increases.
It is also worth talking about the transient mode of operation of the engine, which can manifest itself when approaching an intersection, a traffic light, lying to a policeman, at the moment when the gas is released.
At this moment, a failure may occur - a decrease in speed below idle. The engine seems to choke, it doesn’t have enough air, the reason is an over-enriched mixture. After a few seconds, the situation is resolved electronically.
Therefore, it would be correct to disable the adsorber in the following ways:
- After removing the device, install a nozzle with a diameter of 1 mm into the tube that goes directly past the mass air flow sensor. This will, at least partially, solve the problem, since only air without gasoline vapors will be supplied in doses.
- The ECU is being reflashed (difficult). If it is impossible to remove the Check error, you may need engine chip tuning, which is expensive.
- Dismantling the entire system except the solenoid valve, which operates idle.
- By installing a resistor (valve emulation) in the electrical circuit at 200 - 250 Ohms and 2 watts. To do this, bend the legs of the resistor and insert them into the valve chip. We secure everything with electrical tape. But this doesn't always help.
How to disable the adsorber on a VAZ 2110, 2112, 2114
Taking into account the recommendations above, we do the following:
- Disconnect the power connector from the valve.
- Disconnect all pipes from the adsorber and remove the latter along with the mount.
- We fix the valve in a place where the plug with wires and pipes will reach.
- Connect a hose with a fuel filter to the lower fitting (see photo below).
- To the upper end fitting we connect the pipe going to the intake manifold.
- We put another filter on the pipe going into the tank, similar to the first one.
With this scheme, when the valve opens, clean air enters the system, albeit without gasoline vapors.
We exclude the valve
This method is even simpler. We dismantle everything, including the valve. We put a fuel filter on the pipe coming from the gas tank, and we plug the pipe going to the intake manifold with a bolt and clamp.
The consequences of this method are described above, but this method also has the right to life.
As for Priora, Granta, Lada Largus, Gazelle and other cars, the absorber is turned off in similar ways as described above.
Toyota Chaser
It is worth considering one of the foreign cars, for example, the Toyota Chaser.
The shutdown principle is similar to the previous ones:
- Locate the canister valve. It is located near the mass air flow sensor on the air filter housing.
- Disconnect the chip with wires and all pipes from it (Check may light up on the instrument panel).
- Find the adsorber, disconnect the pipes from it and plug it.
- Disconnect the pipe going to the valve from the throttle assembly and plug it with a bolt and clamp.
- Place a fuel filter from a carburetor VAZ on the pipe going to the tank.
What's the catch in flashing from Euro 4 to Euro 2?
Many people change the ECU from Euro-4 to Euro-2, as a rule, they do this when removing the catalyst and installing a blende. At this moment, the canister valve may turn off (on purpose or accidentally), and the ECU does not control the latter and does not control it in any way.
As a result, if the valve malfunctions, the engine will run intermittently, and the error will not be displayed on the instrument panel. To make sure of this, turn off the valve and observe the operation of the motor.
If the version is confirmed, plug the canister pipes and turn off the valve; the controller still does not control it.
Signs of a malfunction of the control unit
First, start the engine: at idle or in cold weather, you will hear a characteristic, barely audible chirping sound. It indicates that the valve is working properly. In order not to confuse this sound with the noise from a working timing belt, sharply press the gas. The character of the chatter should not change. The following signs indicate a malfunction of the control unit:
- lighting of the CHECK signal on the instrument panel;
- determination of error PO441 during testing;
- increased gasoline consumption;
- unstable operation of the power unit when driving;
- unstable idle;
- increase in CO2 content;
- a hissing sound when unscrewing the tank lid (a vacuum has appeared);
- the appearance of a fuel smell in the cabin.
Error P0441
Owners of Lada Kalina often note that during the operation of the car, error P0441 appears, indicating that the gasoline vapor purge system is not operating correctly (the air flow differs from the norm). The cause of this malfunction may be:
- inoperative adsorber valve;
- clogging of the air line from the control unit to the air filter;
- air leakage through connecting pipes.
What should not be immediately considered is the line from the gas tank to the adsorber; here, a breakdown does not in any way affect the readings of the computer or diagnostic scanner. Still, most often Evap-Solenoid fails; this is a characteristic “disease” on Kalina.
If the EVAP valve stops functioning normally, it is not at all necessary that the engine will lose power, the fuel pump will fail, and so on. Mainly due to problems with the control gear, exhaust toxicity increases, and the Check Engine on the dashboard periodically lights up. There are car owners who do not pay attention to the diagnostic warning light, continuing to operate the car, but do not experience any great inconvenience. And most often in such a case, gasoline consumption does not exceed the norm, the engine starts normally, and no serious problems occur in the fuel system.
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Valve check on site
You will need a tester (voltmeter, multimeter) and a screwdriver. The KPA itself is installed on the radiator frame. The device can be recognized by seeing two tubes approaching it, through which the evaporation moves. Further:
- disconnect the electrical connector from the control unit by releasing the block lock;
- using a multimeter, check for the presence of voltage by touching the negative (black) probe of the device to ground, and the red probe to “A” (the letter on the block connector);
- turn on the ignition: the multimeter should show the vehicle's on-board voltage. If not, check the wiring.
Dismantling the adsorber Lada Granta VAZ 2190
Due to the design features of the Lada Grant, access to the adsorber is difficult. First we perform the following steps:
- We remove the fuel tank from the bottom of the car, unscrew the six bolts around the perimeter, and disconnect the block with wires from the fuel pump.
- Disconnect the canister vent pipe and press the lock.
Disconnect the pipe
- We remove the adsorber, remove it from the retainer, replace it with a new one, and assemble the parts in the reverse order.
Removing the adsorber
How to remove the purge valve
Remove the negative terminal from the battery. If the mass air flow sensor (mass air flow sensor) interferes, remove the inlet pipe from it. Then bend the valve mount and pull it up. Now you need to disconnect a couple of fittings. The first one can be removed freely; to pull out the second one, press the latch and pry up the antennae, for example, with a thin screwdriver.
