Fuel quantity control valve open circuit or short to ground. The vehicle starts and drives ok but is limited to 3000 rpm limp home mode.Ive replaced the control valve on the back of the pump (not a nice job)and checked the wiring in different locations back to the ecu, continuity seem good, i have not removed the plug on the ecu as i have no pin location information.there's a black and purple trace wire which provides power and the a yellow and green wire which is to be earth controlled by the ecu. I've heard that the quantity control valve is reliant on feedback from the fuel temperature switch im not sure as there's very little information on this fault.its a Delphi system any information would be greatly received thanks Darryl