Fuel injection pumps

A fuel injection pump for supplying fuel to an internal combustion engine comprising a housing defining a stepped cylindrical bore, comprising a cylindrical member defining a pumping chamber and having a discharge outlet, said cylindrical member being secured within the narrower portion of said bore, a pumping plunger slidable into and out of said cylindrical member and extending into the wider portion of said bore, a fuel inlet to said chamber from the bore, and resilient means normally biasing the plunger outwardly of said cylindrical member to maintain said chamber at a maximum volume, an annular armature guided for movement by the wall of the wider portion of the bore, an annular field assembly disposed in a space defined between the armature and the plunger, said field assembly being supported by an end closure of the wider portion of the bore, means interconnecting the armature and the plunger and a winding carried by the field assembly, means for supplying said winding with electric current actuating the armature to effect movement of said plunger into said chamber reducing the volume thereof thereby to cause discharge of fuel under pressure through the outlet.