Abstract: A cam for controlling the injection rate of fuel in a fuel injection system having a four part cam profile is disclosed. The first 120.degree. is the plunger advancement segment. The next 80.degree. is the advanced dwell segment. The next 100.degree. is the plunger retraction segment and the last 60.degree. is the retracted dwell segment. The plunger advancement segment is divided into three subsegments: pre-injection stroke, injection stroke, and overtravel stroke. The pre-injection subsegment achieves minimum velocity and acceleration at the start of injection. In the injection subsegment, the cam follower acceleration is achieved as rapidly as can Hertz stress permits to increase the injection pressure and to achieve the maximum injection rate. The overtravel subsegment achieves a sharp and clean end of injection. Preferably, this cam causes injection of less than 20 mm.sup.3 of fuel per stroke during the first ten cam angle degrees of cam rotation.