Alright. Here's the deal. I have a 2.4 SS. I-H-E. Injen intake, ZZP header, GMPP catback. The car ran fine with no CEL's until I installed the header. But ever since, it's been one big problem. It was originally a catless set up. I installed it, and it sounded like ass, so I got a cat installed. It helped a little. The performance is there, but it sounds weird (especially with the auto) and the CEL's are getting annoying. I ran it for a few days catless and it threw lots of CEL's (duh). So I got a cat thrown on and tried to flash it. No luck. So I took it to the dealer who did a full reset. It went away. For a week - until today. It came back on this afternoon. For no reason. I wouldn't even care about a CEL if my car wasn't auto and it makes the t/c light come on and the thing shift hard. I'm so ******* sick of this. Will going back to the stock manifold basically fix my problem? The rear 02 sensor is also IN the cat - will that cause any problems? Could one or both of my 02's be actually bad? The weird thing is that I have a narrowband AFR installed, and when this problem starts up, the gauge stops reading. I just have it hooked to the wire coming off of the ECU. It will then glitch on and off sporadically. ECU / sensor issue? If the problem will automatically fix it's self by installing the stock system and getting another reset, then fine - I'll do it. Not crazy with how it sounds anyway. Even after paying the damn money for the system then getting a cat thrown on. NOT happy.

Thanks in advance.. Help!!

 

if you don't have the stock cat on there with the rear o2 in the stock position, you will throw p0420. You can try ARKs o2 sensor spacer or the anti-fouler mod, but sometimes that doesn't work. The only way to eliminate the cel completely would be getting tuned.

 

So there basically IS something wrong with the header set up? Not just this header, but any aftermarket one? And the only way to fix it is to get a tune or the sensor spacer thing? Will a tune definitely fix it? HPT, correct? What should I look for when doing it? But will a swap out of the factory system and a flash fix it? Can you do a simple scanner flash or does it need a full dealership reset?

 

No swearing in thread titles...

 

Sorry but what was it..? lol I was gonna put ****, because I was pissed off. But was it damn? I really can't remember. lol. But sorry..

 

is it the p0420 code you are throwing? Nothing is wrong with the setup, it's just the car detects non-stock exhaust flow and thinks the cat is bad.

 

I'm not sure on the code. I didn't get it scanned. Just happened tonight. But likely. I tried to get the car scanned and cleared at the parts store initially, but it took a factory scan to clear it, but it's now back. I think I'm just going back to factory, unless doing the HPT reset fully clears it..

 

with an HPTune you can permanently delete p0420.

 

We'll see how it goes. If I can sell the ZZP, I'll just go back to stock. If not, I'll just get the HPT over-ride. And if that doesn't work, I'll probably pay someone to torch the damn car because I've about had it with this thing.

 

I would keep the header/dp, sell the gmpp catback, and use that money to help pay for a tune. Stock catback with zzp header/dp is barely louder than stock. Plus, you will gain more from a tune with header/dp and get rid of the P0420 code.

 

The only problem with that is the stock catback narrows to 2 and 1/16th at the resonator. You would basically negate any gains from the header and downpipe.

 

I've got the same problems man

it's zzp

 

I don't have my stock catback anymore, only stock header/dp.

Here's the deal.. I have a few guys lined up who want to give me 100 plus pay to get my stock manifold back on. But I'd hate to go back to stock after having aftermarket parts. If an HPT tune will definitely fix this, I may just do that. It's 100 bucks.

What all codes will I possibly have that it can totally overrun? I am gonna get it scanned tomorrow, and I'll have them write down all of the codes so I can post them up here and see what the deal is..

 

.. not true.. it's a high flow cat it's a standard.. it thinks there is something wrong... but yes a tune can take out that code..

 

double check your wiring just to be safe

 

What wiring? I've looked over everything 4 billion times. The dealer reset it, stayed off and drove fine for like a week, and now it randomly popped up again. There's a standard cat (02 IN it) and it's an auto..

 

after it's cleared it's got a certain amount of cycles it has to go through before it re triggers

 

The weird thing is that I have a narrowband AFR installed, and when this problem starts up, the gauge stops reading. I just have it hooked to the wire coming off of the ECU. It will then glitch on and off sporadically. ECU / sensor issue?

This is what I am refering to.

Just a suggestion.

 

Nothing is wrong with my ECU wiring. I only spliced into it for the AFR, I didn't cut anything.

But in otherwords, I will need to either do an HPT reset with the ZZP combo, OR put the stock combo back on and do a simple scanner reflash? Or will it need a dealer/HPT flash to reset it even with the stock system on? I don't have a problem with the CEL. I DO have a problem with the t/c shifting issue - in which both seem to go hand in hand.. Will correcting the CEL basically correct the shifting too? It did when I got the dealer flash, but I'm confused as to why it came back, even after a dealer reset..?

 

because it's a cat inefficency code.. it thinks theirs something wrong with the cat since the values arent the same as stock... get a tune and you'll be set..

clearing the code wont fix it

 

So getting an HPTuners tune will 100% fix the issue? The t/c and cel HAVE to go hand in hand, and once you fix the cel, the t/c shifting issue should go right along with it. True? I think it's only a regular cat, could that be the "cat inefficiency" since it's not a high flow one? Is that also why the reset worked for awhile but then came back on after a few days? But by doing the HPT flash it'll 100% fix it? Is there something in HPT so I can totally not permit cel's at all? lol Sorry for all of the questions, but I'm so damn sick of fixing **** on this thing..

 

any tune you get will fix it jus thave to ask to get the rear o2 delete

and the zzp setups use a magnaflow high flow cat

 

So the problem is basically cat/02 related? That's why my AFR isn't working when the cel comes on - correct? Would it have helped it it was a high flow one? A "rear 02 sensor delete" will fix my problem then? Will it also completely disable my afr gauge?

 

if it's a narrow band gauge it's pointless anyways.. if it's a wideband it should be in it's own bung and shouldnt be affected

 

It's a narrow and I know it's not doing much, but it's just a filler gauge.. Regardless, I messaged Bika back (guy who's doing my tune) and he said he's good on fixing it. Looks promising. Anything else I should plan on doing with HPT that will help a mildly modded auto? I guess the rev limiter, governor, and mild tranny tune? Anything else?

So, instead of being 100, the tune was 200. Didn't get it done. So my CEL and t/c light is still on. So, again, you said that the problem will be solved also if you put the stock set-up back on? Will you be able to just do a simple scanner reset or will it need a full dealership one? Aside from that, doing HPT is the only other way to fix this?

Saw this link in an 02 sensor post. WTF? Will this solve my issue cheaply?

http://cgi.ebay.com/ebaymotors/o2-ex...d#ht_500wt_932

Guys, I really need help here on going back to the stock set-up as I will likely be doing this in the next few days if it'll fix it..