Abstract: A fluid injector for a reductant delivery unit includes a fluid inlet and a fluid outlet, the injector defining a fluid path from the fluid inlet to the fluid outlet; an actuator unit including a pole piece disposed in a fixed position within the injector, a movable armature, a spring coupled to the pole piece and the moveable armature, and a coil disposed near the pole piece and the movable armature. A valve assembly includes a valve seat and a seal member connected to the armature and engageable with the valve seat. The armature includes an armature pocket receiving a first end of the spring and the pole piece includes a pole piece pocket receiving a second end of the spring, each of the armature pocket and the pole piece pocket includes an end wall, the end wall of the armature pocket contacting the first end of the spring and the end wall of the pole piece pocket contacting the second end of the spring.