Colt Wagon 2WD L4-1468cc 1.5L SOHC (1989)
Power Transistor: Description and Operation
Ignition Timing Control System
The Ignition Timing Control System is operated by the Multi-Point Injection (MPI) controller. The MPI controller uses all of the engine condition and
vehicle operating condition sensors (during normal driving conditions) to compute the correct spark advance or retard. The MPI controller uses the
power transistor to control the ignition spark.
The power transistor functions to control the ignition timing by interrupting the ignition coil primary current ground causing secondary circuit discharge.
The power transistor assembly is a solid state component.
