what controls the timing

Would like to know what controls the timing on audi a3 car has 130,000 miles on it now runs overly rich. When you go to drive it before it even makes boost the timing goes from 32btdc to8 atdc and it also pulls -12 out of all 4cylinders..and when it does this it also isles at 7atdc any help had it.to 3 audi shops and starting to think if it does not throw a code they are lost,