Can someone confirm...e34 harness. Which is power or ground?

[dunebuggyjay]

Hi guys,

Been struggling getting my obd1 s52 running correctly. O have swappef out evet sensor with no change. No vacuum leaks (smoke tested it)

So im swapping out my wiring harness. I originally had used an e36 harness, but this time i grabbed an e34 harness. Just want to confirm power and grounds. There is a large dia wire that is closest to the dme connector. Is this power or ground? Its very short. Ill see if i can find a pic of what im talking about.

Thanks
Jay

[dunebuggyjay]

After looking at this short wire, closest to the dme connector...its looks like a bunch of brown wires (assuming ground)

Where did you guys hook this up to? Its so short im not sure it will reach much of anything. I could put it on the back corner of the valve cover. It may reach that.

Did any of you lengthen any wires?

Thanks for the help.
Jay

[ian e30 318is]

I used an e34 harness and didn't extend anything, but I did create a new grounding spot in the front battery tray since the wires were slightly shorter than the stock e30 harness. Solid brown is grounding wire. Do you have any pictures of the location?

This might help with e34 harness pin wire colors:


And this might help for the sensor wire colors (look on the bottom right, but the picture might not be large enough):


Are you trying to repin your harness or use an adapter?

[M3PO]

Yep, browns are grounds. Reds are positive. You can ground it anywhere you can get good contact with the chassis. For a clean look, I welded a bolt to the firewall behind the harness covers so my grounds are hidden.