Yup, the ECM is boss, as well as injectors, pistons etc, etc.
Look at the CAPS pump plug in, where the wires go to what looks like the center of the pump. That is the stator or magnet that gets the fuel commands from the ECM. Now if you look close at the connection you will see two wires go to the Stator and two others terminate inside a 2-pin connector like a dead end. That connector is called an ICV (injection control valve) identifier. It is calibrated to the ICV on a test stand. I believe it is simply a resistor, some I have measured @ 900 ohms some were @ 1800 ohms or so. I've been told that you can effect horespower by playing around with the resistance, I have not done it so I can't tell you which direction to change the resistance or at what ohms it will throw a fault.
I will take no responsibility for anyones actions due to this posting. Beware. You are your own warranty station.
Oh yea, I might mention it is pretty hard to fool Mother Cummins when it comes to failures from overfueling. Hot boxes or not , codes or not, they will know, and deny warranty if they choose.
A Johnson