TIAGO

1.2L REVOTRON ENGINE 88 5. Tank Pressure Check Valve The tank pressure valve is provided to keep the pressure in the fuel tank constant. The valve operates according to the pressure inside tank. 1. The tank pressure valve opens out when pressure differential occurs between the tanks side and canister side ports and allows vapour from the tank to carbon canister. When the pressure inside the tank becomes positive and exceeds on established level of 1 – 1.5 Kpa valve opens out. 2. When the pressure in the fuel tank becomes negative (vacuum) and reaches it specified value it open the valve to let the air flow in the fuel tank via canister. 6. Canister Canister made of high grade Nylon, containing special dust free activated carbon is used to adsorb fuel vapours. The lower end of the canister is open to atmosphere for ventilation. The end is not really open but there is foam filter. The purpose of the bottom filter is to protect the canister from dust and dirt during operation. When the engine is inoperative (i.e. while parked) fuel vapours generated inside the fuel tank due to fuel volatility are absorbed and stored in the canister through tank pressure valve. When the engine is running, the fuel vapours absorbed in the canister are purged into intake manifold through canister purge valve operated by ECU. The purging takes place due to air drawn through the canister because of pressure differential between manifold vacuum and atmosphere. 7. Canister Purge Valve The canister purge valve is controlled by engine management system (EMS). The purging of canister takes place because of pressure differential between manifold vacuum and atmosphere. Fuel vapours are drawn into the intake manifold through canister purge valve operated by ECU. Inspection: 1. With ignition switch OFF, disconnect connectors from canister purge valve. 2. Check resistance between two terminals of canister purge valve. Resistance 26 + 4 ohm at 200C. If resistance is as specified, proceed to next operation, check. If not, replace. 3. Blow air into hose removed from T connector. 4. Verify that no air flows through the valve when the engine is stopped with purge valve connectors disconnected. 5. Air will pass through freely when the 12V battery voltage is applied to valve connector. It indicates that the valve is functioning properly. If no air flows, replace the valve. 6. Reinstall valve connector. 7. Reconnect vacuum hoses. Warning: Do not suck air through purge valve. Fuel vapours inside valve is harmful.