An upper guide system for a solenoid actuated fuel injector of an internal combustion engine includes an armature having a first diameter section, a reduced diameter second section, and a concave portion at the transition between the first and second sections. The guide system also includes a guide shaped to extend into the concave portion of the armature and includes a central opening that slidably receives the second diameter section. The guide positions and guides the armature in a radial and an axial direction. The guide is assembled in an axial location that is close to the axial location of the center of the magnetic force acting on the armature. The guide system allows for a desired relative large guide length to diameter ratio.