Probably not a typical mini thing, but
I have a 14point7 gauge and lambda controller. I want to use the narrowband feed to drive the MEMS ECU. I used the 14point7 controller to feed the wideband data to the SC ECU, so I have it almost wired in, after swapping to the MEMS. I will use the wideband feed to drive the gauge.
The wiring diagram for the gauge says, "Ground close to where the lambda controller is grounded."
The controller has two grounds, one for the sensor and one for the heater. Initially I assumed I would use the ground for the heater, but now I am second guessing myself, maybe it should be the sensor round.
The company is slow to respond, if at all and I am not finding much information with searches on using narrowband simulation.
added documentation
Fond the answer in the forum, buried somewhere
Solid AFR Guage wiring
toalan
Nov 2021
Black ground wire on gauge should be grounded to where the Spartan 2 Black wire is grounded. The white wire on the guage, is recommended to be left disconnected.
I'm glad you did, cause I'm having a hard time understanding why it has to be grounded in the same place.......
The vendor replied as well with the same info.