P0420...again!!!

[BeaterEP]

So, finally got my RSX-S exhaust on yesterday. It was a major PITA, since I was working alone, but I got it done.

Originally, the plan was to replace my old exhaust because the cat burned out, and I figured why not go ahead and upgrade a little while I'm at it? Nothing fancy, just a little tweak that also opens up some more room for improvement, right?

Well, took the EP down to get the code read/reset, since I now have a functioning cat, and lo a behold, the secondary O2 sensor already has another P0420 pending.

WTF?! The whole purpose, originally, was to replace the cat so that friggin sensor would STFU, since the county I live in tests for emissions. I was tired of having to deal with workarounds and bulllshit, and figured once I got the exhaust replaced I'd be done w/this crap.

Apparently not.

So, now what? Is there some way to just disable that friggin thing w/o tripping a new CEL?
Seriously, I'm tired of this crap.

Any advice you guys might have, anyone with the same problem, LMK what you did.

TIA

[jtyler05si]

make sure the connector to the secondary sensor is connected properly. this was my fix when i was in the same situation. i bought only one sensor extension connector and used it on the first o2 sensor, thinking the secondary would be long enough. well to find out, it wasn't long enough, atleast not in its original path. i had to lay the wires to the secondary sensor in a different manner. i still used the white clip but not the black metal one (if you have been under there, you know what i am tallking about).

if thats not your case then:
either your secondary sensor is toast
or short/crimp/etc. in the wiring
or you/whoever damaged the connector

did you replace the secondary sensor when you had this problem with the original exhaust?

[Zeth]

^ what he said. check/clean all your connections and sensors. also i was told if your first sensor is messed up then it will send the wrong reading to the secondary sensor giving you the po420 code. its just something you might want to check on.... my car has had the po420 cel on since feburary.

[BeaterEP]

make sure the connector to the secondary sensor is connected properly. this was my fix when i was in the same situation. i bought only one sensor extension connector and used it on the first o2 sensor, thinking the secondary would be long enough. well to find out, it wasn't long enough, atleast not in its original path. i had to lay the wires to the secondary sensor in a different manner. i still used the white clip but not the black metal one (if you have been under there, you know what i am tallking about).

if thats not your case then:
either your secondary sensor is toast
or short/crimp/etc. in the wiring
or you/whoever damaged the connector

did you replace the secondary sensor when you had this problem with the original exhaust?

Yeah, basically the way this all came about was the secondary got fried back when the car was still under warranty. Had it replaced, and a week later the cat ate it (which wasn't covered under warranty )

So, secondary sensor should be fine.

All that aside, I've got an update. So the CEL came back, like we thought it would, but after running for a while (~50-60 miles) it's shut off again, and is still off.
Since there was definitely a P0420 after I switched everything out, but it seems it may have gone away now, I'm wondering if maybe it was just dust/crap in the pipes when I first started up? All the equipment I put on was used (header/cat/midpipe), and it smoked a bit when it first warmed up.
So, is that possible? Could it just have been some dust accumulation burning off and tripping the CEL?

Thanks again.

Oh, forgot to mention, bought sensor wire extensions for both of the O2 sensors, so there's plenty of room in that regard.

[talonXracer]

Did you reset the ECU, if not then it will retain the old CEL#

[BeaterEP]

Yeah, sure did. First thing I did was run to the Autozone so they could pull any existing codes/reset the ECU.

That's when I got the first sign of trouble, guy pulled the code, and tells me that there's a new one, P0420 again, "pending", ie it's new.

So he did a reset, CEL came back on after a while, went back off a little later, and as of the drive home from classes today it's still off.
So that's why I'm wondering if it was just kind of a fluke when it registered a new P0420 after I installed the new exhaust, and whether or not that fluke might have just been dust in the pipes that subsequently burned off.


Keeping my fingers crossed, anyway.

[talonXracer]

It could have been because of storage. Who knows what the A/F was on the car that the exhaust came from, it might have had to take some time to burn off.

[BeaterEP]

That's what I'm thinking...everything seems to be running fine, but on the initial startup after install there was some smoke, not a lot, but enough to notice.
All this stuff was sitting on our balcony for at least a month, and I'm thinking it could have been in this guy's garage since he bought it, for all I know.

So maybe it was just the accumulated crap burning off initially, and now it's done everything has cleared up.

Hey, that's the best theory I've come up with so far, I'm stickin with it till I'm proven wrong!

[jtyler05si]

That's what I'm thinking...everything seems to be running fine, but on the initial startup after install there was some smoke, not a lot, but enough to notice.
All this stuff was sitting on our balcony for at least a month, and I'm thinking it could have been in this guy's garage since he bought it, for all I know.

So maybe it was just the accumulated crap burning off initially, and now it's done everything has cleared up.

Hey, that's the best theory I've come up with so far, I'm stickin with it till I'm proven wrong!

sounds plausible to me. in the diy, it sounds as if the cat was missing some nuts/studs because the guy stripped them. that guy sounds like a possible oaf, who knows what that thing has gone through. He might have left it in his bathtub full of wd40 for a few days, so he could remove the shit he stripped out. now you're just getting done drying/burning it out.

i say as long as the cel doesnt come back soon, ur good to go. plus its only p0420!

[BeaterEP]

sounds plausible to me. in the diy, it sounds as if the cat was missing some nuts/studs because the guy stripped them. that guy sounds like a possible oaf, who knows what that thing has gone through. He might have left it in his bathtub full of wd40 for a few days, so he could remove the shit he stripped out. now you're just getting done drying/burning it out.

i say as long as the cel doesnt come back soon, ur good to go. plus its only p0420!

So far so good. Everything seems to be right with the world again

Oh, and that "only P0420" is a real PITA when you're stuck in one of the few counties in Texas where they test for emissions.
Hell the car always ran fine with that CEL before, I was just getting tired of havin to reset the damn thing before taking it in for service "Hey, you know you got a CEL there, we can fix that for ya *CHA-CHING*" lol

[Bificus]

So far so good. Everything seems to be right with the world again

Oh, and that "only P0420" is a real PITA when you're stuck in one of the few counties in Texas where they test for emissions.
Hell the car always ran fine with that CEL before, I was just getting tired of havin to reset the damn thing before taking it in for service "Hey, you know you got a CEL there, we can fix that for ya *CHA-CHING*" lol

Yeah thats a big cha ching.

[BeaterEP]

Yeah thats a big cha ching.

LOL yeah, that's why I finally said *CH-Screw you guys, I'm just gonna get a better exhaust and install it myself!

[jtyler05si]

So far so good. Everything seems to be right with the world again

Oh, and that "only P0420" is a real PITA when you're stuck in one of the few counties in Texas where they test for emissions.
Hell the car always ran fine with that CEL before, I was just getting tired of havin to reset the damn thing before taking it in for service "Hey, you know you got a CEL there, we can fix that for ya *CHA-CHING*" lol

that sucks

[civicSIracer]

p0420 could be your 02 sensor as well.

[BeaterEP]

p0420 could be your 02 sensor as well.

Nah, it was the cat. Had the sensor replaced not long before the cat started throwing its own CEL, that's why I knew the O2 sensor wasn't the culprit.

Anyway, like I said, now that I've got the RSX-S exhaust on with it's functioning cat, all seems to be well. Been a week now without any issues, except maybe some excessive speed...that thing sounds really nice at WOT on the highway