Stir together the flour, baking powder, baking soda, and salt.
In a large bowl, cream the butter or margarine, 3/4 cup granulated sugar, and brown sugar. Beat in eggs, then add vanilla, sour cream, and orange rind. Beat the flour mixture into the creamed mixture. Stir in the pecans. Pour the batter into a greased and floured tube pan.
In a small bowl, mix together the remaining 1/4 cup sugar, the orange juice, and the liqueur.
Bake at 350 degrees F (175 degrees C) for 1 hour, or until it tests done with a toothpick. Pour the orange juice mixture over the hot cake. Transfer to a rack to cool.