1992 E36 318is question about wire(s) going into the DME.

[agmishka]

Finally got around to seeing what's behind the cover in the DME box. Not to my surprise the harness looks like shit, and I'm pretty sure there are no crimped wires on stock harness. Theres a blk/wht wire that was sitting disconnected (it has a plug) but i have no idea what it is and can't really find much info on it. Should i just try to source a piece of the harness and try to clean up all the connections (obvious answer is probably yes)

[DesktopDave]

There are usually splices and crimps on the factory harness. I know...I was surprised when I saw that too.

That plug you found should remain disconnected. It's the catalyst delete wire; when it's plugged in the car will ignore the O2 sensor and end up with hot start problems. When that's installed, the DME uses the AFM CO pot instead of the O2 sensor. Here's the thread about it.

[agmishka]

There are usually splices and crimps on the factory harness. I know...I was surprised when I saw that too.

That plug you found should remain disconnected. It's the catalyst delete wire; when it's plugged in the car will ignore the O2 sensor and end up with hot start problems. When that's installed, the DME uses the AFM CO pot instead of the O2 sensor. Here's the thread about it.

Wow! Thanks a lot, this is actually even more information on why my car is acting funny.

[DesktopDave]

That's what we're here for! There's a huge amount of info in these forums - seems like someone has posted a solution to every M4x fault at some time or another. I'd recommend searching via Google instead of the built-in SMF search engine.