I have the thing loosened a couple of wrench turns, then it just refuses to budge. I've sprayed some liquid wrench penetrating spray on it. I don't want to risk breaking something in case I'm doing it incorrectly. Do I need to do anything with that nut/cap on the bottom of the cat converter?

Thanks

 

No, leave the bottom nut alone - it is a gas test port. The sensor should be a 22mm hex above an 18mm thread. If it is loose, soak it in penetrant and keep working it back and forth.
However, if you need more force, it is better to drop the cat, remove, and clean up the threads with a 'chase' or 'tap'. Any auto shop sells a double ended spark plug chaser for <$10 in 14 & 18mm.

 

I ended up having to take my entire exhaust system to a local Midas shop and they used a tourch to get it out. After that I did what Garth said and used a sparkplug chase to clean up the threads.

Rodney
86.5 Auto

 

This is what we had to do to mine! This was the spare bung on the X-pipe.

 

wow, I hope I don't have to resort to any of the above stuff!

 

Don't forget to put stuff on the new one.

 

You were smart to have it torched. I had one stick once and I worked it off with a cheater bar, wrecking both the sensor and the bung threads. A thread chaser was not helpful in restoring either.

 

Ok, the old O2 sensor is finally out, thanks to everyone for their advice. In the end I'd shoot some liquid wrench, wait 15 mins, move the thing 1/4" shoot more liq wrench, and so on until it came loose. On a side note, I'll wait until tomorrow to start it, let any liq wrench around the cats dry off and evaporate.

How I do splice this new O2 sensor? The Bosch instructions state that sensor will have either a Shielded wire, or a Non-shielded wire. The old O2 sensor that I just got out, has a wire without any break or plug on it near the sensor, so it obviously needs to be cut. The new sensor has a pretty thin wire, I can see the metal core underneath the insulation. One has far more steps than the other, just want to make sure I get it right.

 

The ones I have seen just use a crimp butt joint.

 

It has the crimp joint at the end of the new one. Seems like I just cut old wire, then splice it into that crimp, heat shrink wrap it, and that's it?

Thanks

 

I got rid of the crimp part, soldered and shrink wrap.

 

If you go far enough up the wire there should be a connector by the fuse panel. If you picked up a "generic" O2 sensor (as most people do) without the OEM plug, just solder it on there.

If the OEM plug is still in the car, it is easier to remove the plug, make the new connection away from the car. Then install the sensor.

I'm in the process of adapting a 3-wire O2 sensor to my 81.

 

NO NO NO! Always solder, crimp connectors are prone to corrosion and they don’t last as long as a good solder/heat shrink connection. Many garages opt to just crimp the new sensor cause it’s easier and faster, but this is not the proper way to do it.

Don’t give out suggestions if you don’t have first hand experience in it.

 

Interesting, why do you want to go from a 1 to a 3 wire? I went the total opposite direction and used a 1 wire during the replacement of the old 3 wire. As soon as the sensor is warm (~30sec after a cold start) I really don’t see any advantage in using the 3 wire.

 

X2 on the soldering. I never use a crimp connector anywhere. Soldering makes it one piece of wire with no resistance and no room for corrosion once it's heat shrinked (shrunk?). I don't even like using plugs, but they're a necessary part for changing parts. Every mechanical connection is a potential point of failure and increases resistance in the wire.


HIJACK-
Question: I'm doing this tomorrow and:
For the three wire (two whites and a black) does it matter which white goes to which white coming from (going to) the O2 sensor when you splice in the new one?