The 5 Ohm portion of the 4 prong ballast resistor limited voltage to the ECU. The 1.2 Ohm ohm portion limited the voltage to the coil.
Assuming I'm reading the wiring diagram correctly, switching from 5 pin to 4 pin ECU eliminated the need for the 5 Ohm portion of the 4 prong ballast resistor. Am I right?