18 gauge should be fine though 24awg wire would be more size appropriate. Splice with the 24 awg wire might look better too. The solder/connection quality will be more important than a slightly larger wire. Be sure to get some acid flux or something for good solder penetration/coating.

Go to the junk yard. Cut the 02 sensor runs off pretty much any bmw with the m54b30 motor. You'll have enough of the same correct size wire of the correct color.

Those really aren't great to use in places that see heat. The solder can heat up, reflow, and have the wires separate.

I'm a fan of butt connectors with no insulation over them. They're very slim and when covered with heatshrink line with adhesive, they're water proof.

Lots of OEs supply those connectors in their wire repair kits. I haven't seen any that supply those solder melt butts.

Where do you find the no shield butt connectors?
I may go to a boneyard but closest is about a 2 hr round trip. I may just try to get it back on the road and when It’s convenient, fix it correctly. It only gets about 2-3kmiles a yr now.


Sent from my iPad using Tapatalk

You can get them on Amazon

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Lifetime supply:

https://www.homedepot.com/p/Tyco-Ele...-000/205878599

Single sided like I think the OE style is.

I'm very excited to see this fixed!

Ended up soldering a combo of the original wires and some 22 gauge wire I had from a stray part. Ran out of flux and time so maybe tomorrow if I can find some flux.

Funny thing, I wanted to take the wires off a junkyard car, just snip and crimp or solder and the two BMW boneyards I spoke to counter-offered that I could buy the entire wiring harness for $400-450 and cut off what I needed. Funny.


Sent from my iPad using Tapatalk

Don't reattach anything until you find the short. Did I miss you finding the short?


Sent from my iPhone using Tapatalk Pro

Dreaded trans. Failsafe prog.
 

Yes, like you thought about midway between bank 1 and 2 most of the 4 wires had fused together from heat about an inch. The bank one upstream was shorting. I cut out the damaged parts and soldered pieces of same size wire as the four wires but ran out of flux and had other stuff come up before finishing. Oddly, no local stores sell electronic flux……tried to get a cell phone guy to sell me some but had to order from AmAzon.

I will test all the connections prior to giving it 12v.


Sent from my iPad using Tapatalk