Creating a pulse for injector drivers

[S. Lastuka]

WE are on a FSAE team and are designing an electronic fuel injection
system from scratch.  We are using the Motorola 68hc11 MCU.  We have
almost all the code written and tested but are having some trouble
creating the pulse sent to the injector drivers.  The trouble is with
using an output compare to create the pulse.  An output compare can be
used to turn off a pulse after a certain time, but how to you turn the
pulse on in the first place?  Please help.