Dylan wrote:I may of explained it wrong. The 2 earth point's on the harness are connected inside the loom with a wire, I think.
I have one pulled apart I'll double check
I have seen this is most OEM looms hence why I follow that route for my grounds but add heavier gauge up to the point where all the other grounds junction from and between the groups. Basically its just the OEM method with better material budget.
As for what VL said about running completely isolated one for the ignition I see the point and agree but I have never done it as I have never built a loom that uses grounded coils as they have all been the V6 style bi-polar coils and DFI modules self ground via the bracket so I don't need to do anything there.
For my next loom it will run LS coils so I will do something different there but that's some time away to even think about it at this stage.
Dylan wrote:I may of explained it wrong. The 2 earth point's on the harness are connected inside the loom with a wire, I think.
I have one pulled apart I'll double check
Gotcha, joining earths together in the loom is common practice and works fine. Its just joining different types of earths together that causes issues with voltage offsets. Widebands are notorious for this with its higher current heater switching circuitry and high accuracy analog output where mV's matter sharing a common earth wire. 14point7 are one of the few that provide two earth wires to get around this issue.
So what I'm taking from all of this is that it does matter how earths are routed but it is often overlooked? Like in the case of the mil spec harness that I came across and as you say VL400 most widebands
I think I'll continue to follow manufacturers specs rather than skimp or cut corners.
I recently helped a mate wire up a Innovative WB into his VS Calais and it only had the one power and one earth wire which I was quiet surprised about after having used the 14point7 gear previously.
as most have always prob said, anything that needs a reference point like 02 sensor then use another earth like from ecu or a separate line that is a stable reference, most other stuff can go on engine block or chassis
