Use butt connectors, potted with dielectric grease and properly crimped, tape over each after crimping, or better yet use heat shrink tubing.

"Properly crimped" means using a full compression crimper:

The tool shown above is from Harbor Freight $15, often on sale for $10.

A full compression crimper actually fuses the wire to the connector body producing a connection that often has less resistance than a soldered connection, certainly no worse. The dielectric grease prevents corrosion, the tape/heat shrink keeps the grease in place.

 

Personally I'd solder, because I've had bad luck with moisture getting into the crimped connections, even with grease. Personal experience though, crimped should work just fine. Just make sure you wrap it with shrink wrap or tape.

And in this case a heat shield or good wrap for the new wire would help prevent it from melting again. At the very least make sure the wires are the maximum distance from the exhaust at all times and firmly secured.

 

I also would solder and heat shrink connections, my next choice would be weather pack connector but that requires a special crimper

 

Properly crimped is the preferred method for both the aerospace industry and the military--examine the connectors on your car and you will not find any soldered connections--other than those in the electronic modules themselves.

Soldered joints have also been shown to be less resistant to vibration and repeated flexing.

The key words however are "properly crimped"; soldering is far preferable to using one of the horrible "squashing" type crimping tools typically sold by hardware stores and FLAPS--they do nothing but deform the connector barrel and if poorly enough designed damage the wire.

 

I have been an aircraft mechanic, heavy equip mech, auto mech for many years and the accepted way is solder over any mechanical connection such as butt connectors. Weatherpack type pin is an exception(alot of these are also soldered). can't think of any factory mechanical butt connectors at this time idk

 

Neither can I, however there are a bunch of pin/blade and socket friction fit connectors in which the harness wires are crimped to the pin and socket.

I used to both crimp and solder, many many years ago, however after reading a number of documents (mostly from SAE) over the years I no longer do so as it is not necessary--again assuming properly crimped, and sized terminals. Google "solder vs crimp -forum*" (the "-forum*" part weeds out a lot of anecdotal type stuff) and you'll find that the preponderance of current thought is crimp only.

This is the first hit from that search, it sums current thinking up quite well...

 

Alright so I think properly crimping wins for fixing the wiring. Now how can I go about getting 1 mil eliminator? They are sold as a pair off of AM, how can i get one? Also, the plug that plugs into the o2 sensor is toasted, i'm thinking autozone? Any better options?

 

Make your own...

And don't get on my case that this is a soldered assembly, choosing appropriate tools and procedures are the key to any successful project--one would not use crimp connectors to attach a 1/4W resistor to a 18ga wire...

 

do not solder the o2 harness due to the fact that solder causes a higher resistance in the wires causing the wires for the heating element to give a different reading and also your air/fuel reading will be off. you can either crimp them together or tie them together and use a clear finger nail polish to coat the bare wire then use heat shrink.

 

This is completely absurd, in fact I have no words to rebuff the profound idiopathic mindset that would lead to such spewings.

Finger nail polish? From what electrical engineering text was that pearl extracted?

 

this happened to me with my headers. Just get some extrra wire, extend the wiring, crimp, use heat shrink, throw some zips ties on it and attach it to somewhere away from getting f ed up again.

 

Quite honestly, crimp or solder is one of those arguments you can't definitively win. Solder is succeptible to creep at high temperature, crimps are succeptible to moisture. Unfortunately you're in an environment with both, and neither is a perfect solution.

The true take away from this? Do it right. [Which means no nail polish.] If you crimp use the proper tools and grease. If you solder, again, proper tools and procedures. If you do it right either way it should last.

And that MIL eliminator DIY link was convenient. My DD Neon just threw a P0420-catalyst 1 below efficiency code, and I think I'll just fab up one of those. Problem solved!