1. EVAPORATIVE EMISSIONS CONTROL SYSTEMS n Chapter 8 n Classroom Manual Page 244 n Lab Manual Page 328 CBC AUTOMOTIVE RK

2. OBJECTIVESOBJECTIVES n Describe the operation of an evaporative (EVAP) control system during the canister purge and non purge modes. n Diagnose & service evaporative systems. n Use scan tester to diagnose EVAP systems. n Diagnose EVAP system thermal vacuum valves CBC AUTOMOTIVE RK

3. EVAP SYSTEMS n Gasoline (Hydrogen and Carbon) HC is a pollutant and must not be allowed to escape to the atmosphere. n Purpose of EVAP is to contain vapors from fuel tank and carburetor when engine is off. n Burn vapors in engine when warmand under cruise conditions. n Burn vapors in engine when warm and under cruise conditions. CBC AUTOMOTIVE RK

4. SYSTEM DESIGNS n Main components are the charcoal canister, purge valve, rollover valve, lines. n Two types of EVAP systems –Mechanical - Vacuum controlled –Computerized - Electrically controlled CBC AUTOMOTIVE RK

5. CHARCOAL CANISTER n Typical canister in vapor storage mode. n Absorbs vapors from carburetor and fuel tank CBC AUTOMOTIVE RK 246C

6. PURGE VALVES n Ford Purge valves. n Typically normally closed n Purges above idle CBC AUTOMOTIVE RK 245C

7. ROLLOVER VALVE n Located in top of the fuel tank. CBC AUTOMOTIVE RK 245C

8. OBD II Evaporative Emission System Monitor n Tests ability of fuel tank to hold pressure n Tests ability of purge system to vent vapors from charcoal canister n Detects leaks and restrictions is EVAP system n Fuel tank will cause MIL light to come on.

9. That’s all Folks!