A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. The VDP includes a variable stop configured to vary minimum displacement of the variable displacement mechanism based on position of the variable stop relative to a housing of the VDP. A pressure sensing valve (PSV) is operatively connected between the inlet line and the outlet line to actuate a stop member to adjust stopping position of the variable stop based on pressure differential between the inlet line and the outlet line.