The trigger signal in piggyback install!

wiring piggyback ecu with the oem ecu in engine that use reluctor sensor. Do I need to feed the piggyback ecu with the both wires of the reluctor sensor or the (+) wire is enough?

Piggyback ecu (haltech)

You should have both ecu sensor earths connected together.

With both ECUs grounded to the same ground. You should only need the (+) wire. Some ECUs have separate ground wires for signals and triggers so you would need to add a signal ground in some cases.

From memory, when I did my Haltech in piggyback I ran the + and - crank signals, but only the +ve on the home cam signal. It depends on the sensor type though.. Reluctor is generating a voltage differential, Haltech needs to see both sides.. I can check tomorrow for you if you'd like.

https://i.imgur.com/Y3aCTWd.jpg