Oxygen Sensor Help

[Chunkerz]

Here's the story: while changing my oil, I decided to replace my oxygen sensor as well because I'm pretty sure it was original to the car. It was frozen in place and wouldn't budge, so I used some WD-40 (didn't have anything better) waited 30 minutes, and used a torch to heat up the exhaust pipe. It still wouldn't move, so I sprayed the rest of the can of WD-40, waited about 2 hours, heated it up again, then used my foot to push the wrench. This time it broke free and I was able to remove it, but the threads on the sensor didn't come out with it

Using a mirror, a small screwdriver, and a pair of tweezers, I was able to pick out most of the threads, but there were still some remaining that I can't get out. I gave up on my picking method and decided to go track down a thread chaser. Sears didn't have it in stock, so I picked up a M18 x 1.5 tap instead. I can get the first one or two threads to catch, but the tap looks crooked (kinda hard to tell since it's pointing away from me while I'm upside down under the car) and I don't want to destroy the threads. When I try to turn it, it gets difficult to turn and eventually pops out, so I'm thinking that I'm cross threading it. Removing the exhaust in one piece seems impossible because the nuts on the headers are welded in place with rust (haven't checked the ones after the cat, but I bet they're stuck too). I have some Kroil Oil on the way, but these seem like they're rusted beyond the point of removal

So what should I do now? I really really really do not want to remove the exhaust because I am hoping to get my NA-Tune soon (if Josh ever ships it ) and I want to have my O2 sensor in place so my car will run right when I install it. If I cut off the nuts for the exhaust that'll add more down time and money to my repair and I just want this POS on the road!

Tl;dr: Threads for my O2 sensor are destroyed and I'm stuck.

Here's what was left of my O2 sensor:

[rick13]

Oh dear...what about just tapping on it. Another thought is, drive it and maybe it will vibrate out. Then do some more picking.

Rick

[Chunkerz]

Will tapping break the remaining threads free? They look more like welds than left over threads... When (or if) my NA-Tune comes I'll try a long super hard drive to see if the heat will loosen them up. Hopefully my car will run well enough for a long drive with the huge exhaust leak and no O2 sensor. Could I just plug in the O2 sensor and set it somewhere in the engine bay? Or would that be pointless and do more harm than good?

While I was down there, I noticed another bung behind the O2 sensor that had a cap on it. What is that thing? It looks like the top of the cap has been welded.

[nightheart]

Just unplug it. The earliest cars were designed to run without them or a cat. If the sensor is there the dme uses its input, if not, if defaults to an open loop cycle. If your running a cat, this could plug it in the long term, but a few weeks/months isn't going to kill it.

[Chunkerz]

Alrighty I'll do that. I don't care about plugging my cat anymore because my car has been running super rich for a lonngg time and it's probably 90% blocked now. It's just begging to be replaced with a resonator or high flow cat.

[John_AZ]

Originally Posted by Chunkerz

Will tapping break the remaining threads free? They look more like welds than left over threads... When (or if) my NA-Tune comes I'll try a long super hard drive to see if the heat will loosen them up. Hopefully my car will run well enough for a long drive with the huge exhaust leak and no O2 sensor. Could I just plug in the O2 sensor and set it somewhere in the engine bay? Or would that be pointless and do more harm than good?

While I was down there, I noticed another bung behind the O2 sensor that had a cap on it. What is that thing? It looks like the top of the cap has been welded.

You might try to find a M18 spark plug thread chaser at a FLAPS. It should have the same pitch.



Your O2 sensor looks like you have some oil contamination also. Rich fuel contamination is a powder white tip.



The "bung" is capped. It used to have a tube that extended to the rear of the cam to test exhaust. The tube usually rusted and most just capped the pipe. The cap should be solid.

If I bought a NA Tune or any other system, I would do a compression-leak down test and have my injectors tested and rebuilt. Changing the FPR & FPD if OEM and rebuilding the TB would be next. Then check for vacuum leaks.

GL
J_AZ

[Chunkerz]

Isn't a thread chaser pretty much the exact same thing as a tap? I couldn't find one anywhere so that's why I settled on a tap.

Fuel pressure regulator/damper are both brand new, but I haven't had a chance to do any extended tests with my new parts because I had to park my car for a while. My fuel injectors just came back from Witchhunter, but I haven't instated them yet. According to the sheet I got with them they weren't that bad to begin with. I rebuilt my throttle body, put in a new J-boot, and replaced my vacuum lines about 2 months ago, but I haven't checked for vacuum leaks yet. I'll see if I can find my compression tester anywhere and use my hard earned Christmas money to get a leak down test.
If it is oil contamination, then hope my cylinder walls aren't scored and letting oil isn't passed the piston rings There wasn't any blue smoke that would indicate that I was burning oil.