Contents: General description ⇊ Models with carburetor ⇊ Fuel Injected Models ⇊ Control ⇊ Hoses ⇊ Battery ⇊
General description
1. The fuel vapor recovery system collects fuel vapors and mixes them with the finished fuel-air mixture while the engine is running.
2. The vapor accumulator is a container filled with activated carbon. The information below will help you understand how the system works
Models with carburetor
Note: This describes the operation of a typical fuel vapor recovery system. There may be some minor differences on your specific vehicle.
3. The fuel tank cap is designed as a two-way valve, which ensures safe operation in the event of failure of the fuel vapor recovery system.
4. Another two-way valve, mounted on the tank, regulates the flow of fuel vapor from the tank to the fuel accumulator and operates on the difference in fuel vapor pressure when the temperature changes.
5. Fuel vapors after the two-way valve enter the accumulator located in the engine compartment.
6. When the engine is turned off, the carburetor shut-off valve connects the cavity of the float chamber with the vapor accumulator.
7. When the engine warms up, the thermal valve at the top of the accumulator will close, and the relief diaphragm will open accordingly under the vacuum pressure in the intake manifold.
8. When the engine is turned off, the fuel supply through the main metering system is switched off by an electric valve and prevents fuel from entering the carburetor diffuser.
Fuel Injected Models
9. When the fuel vapor pressure in the tank exceeds the set level, the two-way valve will open and fuel vapor will flow into the accumulator.
10. The accumulator stores fuel vapors until they are supplied to the engine.
Fig. 10.1a Typical diagram of a fuel vapor recovery system (carburetor engines)
Fig. 10.1b Typical fuel vapor recovery system (models with injection)
11. The battery is unloaded through a diaphragm controlled by a thermal valve: up to a coolant temperature of 55 degrees Celsius, the vacuum from the intake manifold is not supplied to the diaphragm; when this temperature is exceeded, the diaphragm opens and the battery is blown with fresh air, carrying fuel from the battery into the throttle space.
Control
Note: The chance of failure of the fuel vapor recovery system is very small. The most common failures are the hoses and the fuel vapor accumulator.
Hoses
12. Inspect the hoses first according to the connection diagram fixed inside the engine compartment, usually on the hood. Replace damaged hoses.
Battery
13. Remove the battery from the vehicle.
14. Warm up the engine and set its speed to 2500 rpm. If the battery is working properly, you should feel suction. Otherwise, replace the battery.
15. Disconnect the inlet hose and plug the inlet hole with your finger.