Jack, as I said before, I think that is the AEMnet data line. There is probably another one from that unit plugged into the logger. I thought we logged pressure, and I thought it was from that sensor... but that data is on a computer that died years ago... I suspect from excessive exposure to the salt. It had tuning files we used in 2003-2008 for our assault on the 1000cc bike records... It had the data files when we used the equipment I sent you to help tune Max's streamliner in 2012....
so I am working on 6 year old memory... and you know how much 6 year olds remember
If that is the back pressure sensor wire, then it was not needed for Max's bike since that is only used in turbo installations, I put the pressure sensor on it because it was in the box of stuff we used and I thought we used it to monitor boost, otherwise it would have been capped like the daisy chain AEMnet data wire.
The group of red wires goes to power, the group of black go to ground, I think the separate red is switched power and the remainder are the sensors. Hook it to a battery and a laptop with the AEM logger software on it and it should work. It came off Max's bike as a unit and went into the box.