I've got a 98 prelude in the driveway right now.

It was brought to me for a brake job and while I had it up, I noticed an oil leak. I fixed that (sandwich plate seal was shot) and when I took it for a test drive, I noticed a cel, so I read the code, secondary O2 sensor.

I got under the car and saw an oxygen sensor tied in a knot around the swaybar, and the secondary oz sensor that was screwed into the cat had the wires cut off.

I've tried everything to get this sensor out.

Soaked in PB blaster
vice grips and then lifted with a jack to turn the vicegrips, still didn't break loose
I've done a half dozen heat cycles with mapp gas, cooled with water, tried loosening while hot, tried loosening while cooling

The flanges/bolts on the cat are so rusted that they're not going to come off without having to be replaced, and the owner wants to keep the bill under 200, I'd have to charge alot more if I ended up replacing bolts/cat/welding etc

Are there any tricks to removing a stuck O2 sensor? I'm going to pick up the socket when I run to vato zone, but I doubt it'll make any difference.

Is there anything I could do as far as simulating the sensor? The downstream just double checks the signal from the upstream sensor, correct? The maps don't get adjusted off of the secondary sensor afaik, so is there a cheap n easy way to trick it?

 

this sounds crazy but i had the same prob. i took the cat off and used a pipe wrench. or monkey wrench whatever they call it...

 

Have you tried putting on some penetraiting oil on it yet? Had the same problem with my downstream 02, but the oil did the trick.

Also what you can do is cut the 02 sensor wire, so all you'll have is the 02 sensor itself sticking out of the cat. Next what you will do is take a dremel with a cutting bit and cut it down to size to stick a socket on it and try it that way.

 

I can't remove the cat without having to replace the bolts and possibly a flange or two. It's rusted to ****, which leads me to believe her poor fuel economy could also be attributed to a **** cat.

I called the owner, talked about it, she'll bring it back in when she's out of school for the summer and have me replace the cat when I do timing belt.

O2 sensor is siezed, it will not be coming out of that cat. Cat's shot, so I'm just going to leave it until she brings it back in.

But I still have the question, is there any way to fool the computer into believing the sensor is there and everything's good? I was thinking a duplicate signal of the primary sensor? Does the downstream sensor cause map adjustment?

 

https://honda-tech.com/zerothread?id=821015