4 & 5 pin ECUs
Kit's
explanation as to the internal regulation of the ECU's power.
Chrysler's introduction of the factory system
1972 Imperial & Chrysler Ignition System Service Book (Session 292)
Good clue here...
Start and Run have seperate routes to the power the ECU and Coil
Ignition Start provides power to coil without going through the 0.5 ohm resistor.
Ignition Run is J2 (blue)
Factory Ignition wiring for 1976
View attachment 1715948429
A 4pin replacement ECu doesn't use the 5 ohm resistor for regulating its power.
The ECU gets its power only through the top pin.
View attachment 1715948436
