Figure 7.28. Location of Fuel Vapor Capture system (EVAP) elements on models before 2001: 1 – crankcase ventilation valve; 2 – vacuum modulator of the exhaust gas reburning system; 3 – exhaust gas re-burning system valve; 4 – fuel vapor pressure sensor; 5 – fuel vapor pressure sensor vacuum valve; 6 – container with activated carbon; 7 – fuel vapor recovery system vacuum valve; 8 – oxygen sensor (block 1 sensor 2); 9 – vacuum valve of the exhaust gas reburning system; 10 – oxygen sensor (block 1 sensor 1)
Figure 7.29. Location of Fuel vapor capture system (EVAP) elements on models from 2001: 1 – crankcase ventilation valve; 2 – fuel vapor recovery system vacuum valve; 3 – equalizing tank; 4 – Fuel vapor recovery system service connector; 5 – vacuum valve of the activated carbon canister closing valve (CCV); 6 – fuel valve; 7 – pressure control tube; 8 – ventilation tube; 9 – fuel tank filler cap; 10 – return hose; 11 – fuel vapor pressure sensor; 12 – vacuum valve controlling the pressure valve; 13 – air supply hole; 14 – cleaning hose; 15 – canister with activated carbon; 16 – fuel vapor emission control system hose; 17 – fuel tank
On models produced since 2001, the activated carbon container is installed in the engine compartment, and on models produced before 2001, it is located under the car, behind the fuel tank (figure 7.28, 7.29).
When the engine is not running, fuel vapors are transferred from the fuel tank, throttle body and intake manifold to the activated carbon container, where they are collected. After the engine is started, fuel vapors are removed from the tank through the purge control valve and fed into the engine cylinders for combustion. The cleaning control valve is controlled by the engine control unit.
The fuel filler cap has a double-acting check valve. If the fuel vapor recovery system malfunctions and the pressure in the fuel tank increases, the valve releases fuel vapor into the atmosphere.
Figure 7.30. Location of the fuel vapor pressure sensor on models produced before 2001
The fuel vapor recovery system includes a pressure sensor (figure 7.30), which reacts to changes in fuel vapor pressure. On models prior to 2001, the sensor is mounted on the engine compartment bulkhead, and on models from 2001 onwards, it is located on the top of the fuel tank on the fuel pump/sensor assembly.
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After the engine is started and warmed up to a preset temperature, the vacuum valve (VSV) opens, opening the purge valve, causing a vacuum to be created in the intake manifold, drawing fuel vapors out of the activated carbon canister. The fuel vapors are then mixed with the air entering the engine and burned together with the fuel mixture in the engine cylinders.
The fuel vapor pressure sensor, located in the fuel tank, monitors the vapor pressure in the fuel tank and when the pressure exceeds a preset threshold, a vacuum valve opens and the fuel vapor is released from the tank and collected in a canister containing activated carbon.
Replace the activated carbon container as follows:
- turn off the ignition and disconnect the ground wire from the battery;
- on 2001 and later models, raise the rear of the vehicle and support it with stands;
- label and disconnect all electrical connectors and hoses from the activated carbon container;
- unscrew the bolts and remove the container from the engine compartment or from under the car.
Installation is carried out in the reverse order of removal.