The following injector driver circuit is designed to work with most Engine Control Module (ECM) as well. It is used to drive
the other two injectors in a four injector throttle body in which ECM
drives two of them and this device uses one of the injector drive lines
as the trigger signal to drive the other two.
This Injector Driver Schematic Diagram uses two injector driver chip LM1949
that controlled voltage drops in the ECM, two TIP122 big transistors
(Q1 and Q3), two NPN transistors (Q2 and Q4) to invert the signal from
the op-amp and limit the voltage swing to +5V to protect the input on
Completed materials and components of the Engine Control Module and Injector Driver Schematic Diagram can be download here in pdf filetype.