Ford Repair: 1993 escort and smog check, air fuel mixture, vacuum leaks

Question
did not passcal. smog due to leaking fuel evap-- what is a fuel evaporative conrol?

Answer
basically

fuel evap control is the control of fuel vapors-years ago excess gas fumes went to a charcoal canister and evaporated out into the atmosphere a little at a time-now you have a sealed fuel system but you still get fumes sometimes they need to be bled off so the fumes at times are released through the evap system from fuel tank to the engine where they can be burned with the air/fuel mixture this is done by a pump or valve basically supplying a vacuum or pull from the fuel tank to the engine it is controlled by the computer controlling valves and/or solenoids every now and then the computer will close solenoid and either from engine vacuum or a leak detection pump will pull a vacuum on the system from the tank to engine-if it holds vacuum for so long it will pass the test-if vacuum leaks down depends on how fast you will either show a small or large leak and will fail test-start by cleaning off or replacing fuel cap then take to a repair facility if that doesn't fix it.