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LC-2 Wiring to Relay Board

Posted: Tue Mar 29, 2016 9:01 am
by wadehilts
Hello all,
I'm currently installing a fuel control system in my '87 Peugeot 505. I have added an Innovate LC-2 O2 sensor. I'm using the MSII V3 mainboard with a relay board. Unlike the LC-1, the LC-2 only has one ground wire. I am aware that sensor grounding can be a sensitive factor, and noise should be eliminated wherever possible. This presents a quandary with the 1 ground wire setup: I don't want to introduce a relatively high-current ground into my quiet sensor ground line, so I have grounded the O2 sensor at the Engine ground terminal on the Relay board.
On the other hand, I know that it is important that the LC-2 O2 sensor portion have the same grounding potential as my Megasquirt. It does tie into my Megasquirt's ground pool eventually, but certainly doesn't pass through the ground plane in the MS.
Why has the LC-2 moved to a single ground wire? In the instructions for the LC-2, they say to ground to the battery terminal - which I have <0.5 ohms resistance to the battery terminal at my engine ground point, so I think I'm OK there. I'm just worried about sensor grounding potentials lining up.
Maybe I'm just worrying too much!
Wade

Re: LC-2 Wiring to Relay Board

Posted: Fri Apr 01, 2016 7:00 am
by Matt Cramer
It's best to ground the LC-2 to the battery, not the relay board. Apparently the three ground wires in the original LC-1 caused too much customer confusion.