An upper guide system for a solenoid actuated fuel injector of an internal combustion engine includes an armature and a guide ring having a cylindrical shape and surrounding the armature and positioning the armature in a radial direction. The location of the upper guide system is substantially in the same axial location as the radial magnetic forces imposed on the armature. Features such as flutes or grooves are disposed on an outer diameter surface of the armature and/or holes through a body portion of the armature. Accordingly, the response performance of the solenoid actuated fuel injector is improved.