A fuel injection system for an internal combustion engine includes an air flow responsive throttle element in the induction tube which is subject to an adjustable elastic restoring force. The throttle element is attached to a bushing which rotates about a pivotal shaft mounted within the induction tube. A control slot in the bushing is covered to varying extent by a control edge on the pivotal shaft so that fuel which enters a groove in the shaft is metered out according to the relative rotation of shaft and bushing. The relative position of the throttle can be adjusted by a pressure cell.