MD83FO
From IAF to IF>FAF segment if the intercept angle is sharp then on the chart there is a lead in radial or bearing drawn from the nav aid only after crossing that radial it is permitted to change the intercept heading to more suitable one but when radar vectored if you are given a heading to intercept then you must intercept the LOC on that heading. Also when in HDG mode if you did not activate approach and intercepted LOC (obviously in select speed)unless the decel point is ahead of you it will not auto activate and when you go managed speed will increase to 250KTS.