91 excel injectors sensor on 1991 Hyundai Excel

I am working on a 91 excel, the fuel pump is running and I have gas after the filter to the injectors but I am not getting 12 volts to open the injectors? Where is the sensor and what sends voltage to energize the injectors.

Asked by for the 1991 Hyundai Excel
12 from ignition switch is constant with key on. the ground is controlled by looks at the crank sensor for a trigger. you might want to start there.