Abstract: A fuel supply manifold in a returnless fuel system for supplying fuel to an internal combustion engine has a fuel rail with a first end having a first opening and a second end having a second opening. A one piece end plug, which fits into the first opening to provide closure thereof, has a fuel hose connector with a fuel inlet therethrough to pass fuel to the fuel rail and a fuel temperature sensor in close proximity to the fuel inlet. The one piece end plug also has an electrical connector casing for receiving an electrical connector to conduct the fuel temperature signal to a remote location for processing. A flange on the end plug attaches to the fuel rail with a pair of bolts, and a core with O-rings thereon extends from the flange for locating and sealing the end plug to the fuel rail. The second end is capped so that fuel may not flow therethrough.