I am working on a patch harness for a Magneti Marelli IAW 16 ECU to MS2 conversion for a MV Agusta (Ducati / Fiat) system.
The sensors and accessories are pretty straight forward but can't figure out the ECU power and relays control...
Unlike the conventional relay layout like the core wiring diagram in the MS manual with an ignition switch controlled Main relay + an ECU controlled Fuel relay, MV Agusta uses the following:
- a main relay controlled by the safety switch (kill switch) / ignition key with a low power line to ECU. (middle relay in the diagram)
- a fuel relay (power relay) controlled by the ECU for the fuel pump,coils and injectors (equivalent to MS2) (bottom relay in the diagram)
- a main ecu power relay (Latch relay) for a high power line to the ECU also controlled by the ECU (top relay in the diagram)
The MV Agusta relay board is a single PCB I wish to keep stock.
I considered:
- GND Switching the Latch relay (OEM pin 4) with an unused MS I/O (not sure if possible).
-Bridging the Latch relay control wire with the Fuel relay control wire and doing something with the high power wires (not sure how).
-Keep the Latch relay unused but I doubt that the ignition switch controlled power line is up to the MS power demand and am unsure about unforeseen effects on the system.
Suggestions are very welcome.