PO Removed Cat (but left cat hair)

[2kSL1]

Cat hair I can take care of with a lint roller, but an absent Cat has me concerned that I may be running lean. Not surprisingly, my post-cat oxygen sensor is burnt out. The missing cat and fried O2 sensor are the only things throwing codes right now.

I have a laundry list of parts to replace, and suspension and exhaust are the most expensive parts on that list. I called several local salvage yards and they all say they pull the cats, so I'll have to buy a new one, but a header back exhaust and O2 sensor on eBay comes to $436 on the cheap end! What I would like to know is if I can expect to find a header back exhaust (maybe with an O2 sensor still in it) at a junk yard - or if the missing cat will pose a problem beyond the CEL . Should that be a high priority repair?

Also - How far back can I look for exhausts for a 2001 SC2? What's compatible?

[fetchitfido]

Cat-back your fine with '91-'02 SL/SW ('97-'02 SC). Downpipe (from manifold) back to the flex-pipe/catalytic converter, your stuck with the 9 bolt manifold downpipes, '00-'02.

Stock catalytic converters that haven't been punched out are worth a pretty penny of quick cash. It's a lazy/stupid junkyard that leave's the catalytic converter in place.

The "missing" catalytic converter is a sorta easy, generally $30-$40 fix. If you have inspections, you just wire in the simulator so it looks like the exhaust is acting right even though the rear O2 isn't plugged in.

[2kSL1]

Thanks for the swap info. No inspections required in MI, I just don't want to burn any valves.

[fdryer]

The O2 sensor, when operating (with or without a catcon), doesn't care if the catcon's there. The O2 sensor measures oxygen content from the exhaust, before the catcon. Its sensing rich or lean mixtures and sends feedback signals to the pcm to correct rich/lean mixtures to a narrow range for emissions control. As long as the EFI system is operating correctly, the engine won't run lean or rich at all. The catcon's job is to "freshen" the polluted exhaust as much as possible as long as the front O2 sensor is working. The cat is just for everyone that drives behind you so we won't choke on the freshened exhaust.

As long as the EFI system works and the O2 sensor isn't giving any code(s), your engine is fine. The exhaust not being freshened by a missing catcon just makes the rest of us choke. Other members in states not requiring emissions inspection haven't had any issues with their catless systems.

[2kSL1]

So if I just replaced the O2 sensor, everything should be fine? I thought a missing cat would burn out the O2 sensor. But now that I think about it, I guess the upstream sensor is fine... well, thanks for the input. Ill replace the sensor for now and replace the cat when I finish my other high priority fixes. I'm more interested in being green than having a few extra horses

[BV22]

The car has two O2 sensors. The "front" one that fdryer refers to is in the exhaust manifold right behind the radiator. Feedback from this sensor is essential to have the engine run right. The "rear" sensor is the one just behind the cat. Its only purpose is to spy on the performance of the cat. Since you don't have a cat, you are likely getting a P0420 code. The rear sensor is setting that code.

[2kSL1]

Oh, I know it's the downstream oxygen sensor code, got it read at Autozone. I picked up some 18mm spark plug non-foulers to put on my sesnor to get rid of the code, but the stupid sensor is so rusted in, even after some PB blaster and banging on it, I couldn't get it off using my leg to push on the wrench arm!

Any ideas for getting off an oxygen sensor that is a bit rusted on? Would the same advice work for a stuck on transmission drain plug??

[adventureoflink]

Originally Posted by 2kSL1

Oh, I know it's the downstream oxygen sensor code, got it read at Autozone. I picked up some 18mm spark plug non-foulers to put on my sesnor to get rid of the code, but the stupid sensor is so rusted in, even after some PB blaster and banging on it, I couldn't get it off using my leg to push on the wrench arm!

Any ideas for getting off an oxygen sensor that is a bit rusted on? Would the same advice work for a stuck on transmission drain plug??

At this point you may need a torch for the O2 sensor (and don't forget the anti-sieze for the new sensor)... as for the transmission drain plug, perhaps a long breaker bar will work?

[2kSL1]

Originally Posted by adventureoflink

At this point you may need a torch for the O2 sensor (and don't forget the anti-sieze for the new sensor)... as for the transmission drain plug, perhaps a long breaker bar will work?

Like, blow torch the sensor and then try to crank it out? If it's throwing a code for lack of a cat, does that mean that the sensor has to be replaced? I was hoping I could just throw on a spark plug non-fouler to take care of the code.

[colonelhogan44]

Originally Posted by fdryer

The exhaust not being freshened by a missing catcon just makes the rest of us choke.

I couldn't resist.

http://www.youtube.com/watch?v=CBGsp...eature=related

[fdryer]

^ Ouch!? That song is .............. a little off but very appropriate?

[2kSL1]

So I picked up a propane torch to help me remove the old sensor. I'm supposed to heat the bung, right?

Try to avoid heating the sensor at the same time?

Am I supposed to heat it until it's glowing?

After heating, how much time do I have to get my socket in place and start cranking my breaker bar?

Should I be able to jar of loose with a regular 10" ratchet or should I keep trying with the breaker bar?

I picked up an extra oxygen sensor, but is there any chance just putting the spacers on my old sensor should work? If there's no chance, I'll put in the new one while I'm down there, but if I can get away with it, I'd prefer to return the (expensive) new sensor.

[ssewall]

You understand there's no point in even having a rear sensor other than to plug the hole if the cat isn't present right? You'll get p0420 no matter what you do; the only purpose of the rear sensor is to set that code, which will get set unless you have a cat.

[2kSL1]

My understanding, as per a post from OldNuc, is that if I put an 18mm Spark Plug non-fouler between the sensor and the pipe, it would "fool" the sensor into thinking the catcon is fine and it would get rid of the SES light. That's my main goal, to get rid of the light from the O2 sensor, and I'd like to do so as cheaply as possible

[ssewall]

Ah sneaky! I would even wonder if an inspection state would catch that. Probably not worth the risk as the EPA takes emissions tampering very seriously.

[2kSL1]

Originally Posted by ssewall

Ah sneaky! I would even wonder if an inspection state would catch that. Probably not worth the risk as the EPA takes emissions tampering very seriously.

I had a little 1.6L Suzuki X-90 in Cali without a catcon. I had to change the aftermarket headers to a CA-approved piece to register it, but they had no issues with the missing cat *shrug*

[2kSL1]

So the butane torch did the trick (along with a breaker bar), I got the old O2 sensor out. It looked black, so I cleaned it off with brake cleaner and tried to knock out some gunk to see if I could save it, but I doubt it'll work.

Anyway, OldNuc led me wrong. I got the 18mm Spark Plug Non-Foulers but they have the wrong threads. Won't screw on to my oxygen sensor for nothing, nor would they screw into the bung hole. So I ordered the regular O2 spacer thing designed for this application, I trust it should fit.

I'm getting a new rear 02 sensor from eBay to install along with the spacer and HOPEFULLY this will solve my stupid CEL issue.