Evaporative Emission Control System Purge Flow Monitor
Possible faults which could cause your Mercury Cougar to have an EVAP Purge fault include:
- EVAP canister purge control solenoid valve stuck
- EVAP control system pressure sensor and/or circuit fault
- Loose, disconnected or improper connection of vapor hoses
- Defective EVAP canister
- EVAP canister purge volume control solenoid valve circuit
- Blocked purge port
- Closed throttle position switch
Insure your Mercury's EVAP purge solenoid is functioning properly. By applying 5 - 9 volts you should here a click indicating the solenoid is working. The system sets an EVAP Purge Fault trouble code when there is an electronic problem involving one of the EVAP sensors or solenoid, or when the EVAP control system finds a leak between intake manifold and your Cougar's charcoal canister.
Note also the EVAP system only purges when you're driving your car and on the throttle. If the TPS (Throttle Position Switch) is defective the ECU will set a EVAP Purge trouble fault code, usually trouble code P1447.
Lean Fuel Mixture - Any condition which will cause unmetered air to enter your Mercury's combustion chambers will cause high hydrocarbons (HC). This condition is called a lean misfire. Faults such as vacuum leaks and gasket leaks can cause lean fuel/air mixtures. Broken, disconnected or misrouted vacuum lines will do the same. It is also important to note that many engine components rely on engine vacuum for proper operation. If any of these components are defective they may cause large vacuum leaks. Any vacuum leak can introduce "unmetered" air to the fuel mixture, leaning the fuel mixture and possibly causing high NO, and HC misfires.
