HELP!!! Tune for LT's?
 

Alright so i got my headers done about 500 miles ago, and the car has run awesome since then, but this morning it just decided to run like s***, it started with what sounded like just a few puffs every now and then at idle then it slowly got rougher and rougher at idle. Now below 2K it runs extremely rough it bucks and kinda wants to back fire and then when about 2k it evens out and runs decent.... Also when outside the car, it smells EXTREMELY rich. No idea, guys im talking too say i shouldnt need a tune. I have race headers so all the emissions are gone.
Maybe a bad o2???
Need a tune???
Need new o2s???
I did NOT put the rears back in.. i dont think i should need those, pretty sure those are just to make sure the cats are there..
Also it is an open y pipe at the moment if that matters..
Before i put on the y pipe i ran open headers for maybe 200 miles..
Im thinking its running soooo rich that it just cant run right, and then when i get a little higher in the rpms it all evens out...
Not sure at all what to do, a buddy of mine has my exact car pretty much and he did all this stuff a while ago and had zero problems that i know of..
And HELP!!!
Thanks in advance!!

Yea, you need a tune to get the proper gains out of headers ASAP. As for the gas smell running like crap, does it make any difference if the car is in open or closed loop? It's also possible your O2's are messed up....were they coated headers? That coating has been known to burn off and cause O2 issues. Also, are you absolutely sure there's no exhaust leaks? Hear any puffing or ticking sounds? Headers on these cars are notorious for leaking, which will make it run rich and get shitty mileage. Are you getting any codes?

Im pretty sure there isnt any exhaust leaks off the head, but il check again. But the puff sound i was talking about i am %100 positive it was coming out of the end of the y pipe. I just sounded like it was pushing air.. and it was doing that right before it started running shitty

There a painted pacesetters and then i painted them with high temp paint..
And then im not sure on the open or closed loop, how do i know tje difference?
How do i know if the o2s are bad??

Well an exhaust leak at the collector or Y-pipe is just as bad as at the header gasket....get your collector fixed ASAP.Your getting O2 sucked up into your exhaust via the leak and confusing your PCM into dumping gas and making it run like ass.

What collector? Im running an open y pipe right now.. if thats what your thinking of. If your talking about the header to the y, there isnt any leak there.
Also i WILL check all of this but, would this cause it to run like ass below 2k then run good above that???

First of all, you need to fix your exhaust leak...that is a problem that needs addressed pronto. Open loop is the mode the PCM goes into upon cold startup....it does not take any O2 sensor readings at all...just the preset fuel trims in the PCM, once the car gets up to operating temp it SHOULD go into closed loop, with the O2's poviding constant feedback to the PCM....if you take out the O2's it will STAY in open loop constantly running rich.

If you scan the car, you should be able to see the O2 sensor reading fluctuate back and forth (in closed loop)....not stuck on a certain voltage. Good luck!

:jest: LMAO....your running an open Y-pipe and wonder why your car runs like ass? :lol: Every header has a collector...it's where the header primarys merge to meet the y-pipe. Get an exhaust system dood! Of course it's gonna run like ass with a half assed incomplete exhaust system...LOL.

Shitt.... Lol alright good thing its going in to get welded in a couple days..
Alright and as for the open closed loop, it runs fine when its from a cold start up, its when it warms up it runs rough

I never had a tune for headers. Get your exhaust on and all together without any leaks and go from there. I would get some band clamps. If it still runs like crap it could be an o2 sensor maybe.

ordered 2 new o2 sensors tonight! Figured might as well do them both

Just an idea, but maybe check for a burned plug wire touching one of the headers. I had that randomly happen with my car with manifolds on. The car was running great and then all of the sudden started running horrible. After a ton of trouble shooting found one of the plug wires sitting right against the manifold.

O2's just hate longtube headers for some reason. Maybe cause there not getting hot enough? Idk..

Ya idk, im getting the exhaust welded up tomorrow, and the o2 should be here friday sooo cross my fingers!
Anyways since i have to wait on all this stuff iv been driving it lately and it drives fine when you get going! i just hates idling and starting from a stop... lol but i drove it about an hour both ways on the interstate today and it ran great or than when in 6th at about 1500k then i sputtered a bit

whats wrong with an open Y? wouldent it be the same has a cut out right after the Y that i see people have all over this forum use? just curious?

I basically have an open y pipe, just a bullet hanging off the end. As long as you have no exhaust leaks and your o2s are good you should be fine.

I ran an open y for a few years and never had the car skip a beat. Ran well(not like Ass) and if anyone tells you it hurts performance stop taking their advice.

:cool: do think its a bad o2?

It could be the o2 sensor/s. Make sure that you don't have Bosch o2 sensors. They plain suck. Seems that with it running better after you get into higher rpms that the sensors have gone bad or the wires for the sensors have gotten too close to the header and melted together. Did you use premade extensions or extend the wires yourself? It doesn't have a mis or anything, just runs like crap until you get on it?

Pretty much! But its not even that, i can be barely on the gas at all, once its past 2k it runs fine! And I have extensions no homemade. And i just got ac delco o2s that i need to put in. Is there a way to do it? or just plug them in and go?