AlisonC5

you install headers and delete the front 2 02 sensors? Is the car drivable, does it run rough? I guess what I'm asking is... after header install do you need to get the car tuned asap?? is it harmful to the engine?

Thanks

C5Natie

Without a tune it will most likely throw out a few codes. The motor itself will not be harmed at all with headers. The computer just wont recieve input from the O2sensor and it will run in "reduced power" mode. A simple tuner like a Diablosport can delete the sensors and the car will run fine. Most headers come with O2 bungs but having a muffler shop weld one in should be really cheap. Bottom line, get a tune if you can.

Y2Kvert4me

It might run rough, it might run good. Depends how good your current tune is. The car should definitely not go into reduced power mode, but yes, it will throw a bunch of 02 sensor-related codes.

By not connecting the front 02s, you are effectively removing the fuel trims.
This can be a good or bad thing. If your tune is spot on, or you're in the process of tuning (where eliminating the trims as a variable can be helpful), the car should run as good as it did with the 02s in place.

But if you don't have a wideband in the car, and don't know exactly what your a/f ratio is doing, then it can be a recipe for disaster....definitely get it tuned asap, and drive it very lightly until then.

Headers will typically make the car go lean, and normally, (with the 02s in the loop), your fuel trims will go positive, which means the PCM is adding additional fuel to maintain desired a/f ratio. By not connecting the 02s, you are losing that additional fuel compensation, the PCM is just supplying fuel from tables of pre-set values, and not considering actual running data (from the exhaust) anymore. That is why you need to get it tuned asap.


My reply was based on no FRONT sensors (the ones in the header collectors). If you are talking about deleting the rear sensors, (behind the cats, if any), then no big deal, ignore the CE light and codes, and drive it like you stole it until you can get it to a tuner.

AlisonC5

Thanks for the very informative replies!!! I guess I was thinking the headers did not have a provision for the 02 sensors....

Which brands of headers do have 02 provisions?? I will be using a catted xpipe btw for the rear sensors.

Thanks for the help!!

Oh, car has never been tuned. all stock right now.

Y2Kvert4me

ALL headers (unless custom made to specifically delete them) have provisions for the front 02 sensors.
Most also have provisions for the rear sensors (even those w/o cats).

Just connect all your 02 sensors into the new headers, and enjoy.

AlisonC5

aaaaahhh, so simple, even a caveman can do it! Thanks

XtremeVette

I do believe that when you move the rear o2 sensors to the front that you probably won't throw any codes or even if you do, you will be able to drive it successfully to your tuner. This is an excellent question as Iam going to be installing headers and I never really even thought about this being an issue. My tuner is about 180 miles away. I will have to mention it to him but Iam pretty sure he is already aware that Iam installing the headers myself,then driving the car to him 180 miles away to have it tuned. So Iam right in there on this thread....I will let you know once I talk to my tuner next week, and what he says.

Y2Kvert4me

That is an issue that applies to one brand of header, and no, it isn't an issue, just follow the instructions, and don't cross the wiring to the front harnesses, no matter how the sensors may seem to be oriented.

That is an entirely different topic than what was originally posted, I guess as was the real intent of the topic originally posted too.

If you want a specific answer to a specific question, simply be specific as to what you are installing when asking, it can promote more replies, and save some of us a lot of typing.

XtremeVette

I think we might both be right...I mean help me out but for what reason would you ever want to delete your front 02 sensors? Pretty sure you have to have these to pass any type of inspection correct? So the way I interpreted what alison was asking was that she is putting headers on the car and going to have to delete her 02 sensors because she is going to headers. BUT, she shouldn't be deleting them at all. She should just be moving the stock rear 02's to the front of the headers.

So I agree think she might have gotten confused and with everybody posting we have helped straighten her out.

Y2Kvert4me

Everyone is confused here.

99% of all headers simply retain the use of all 4 stock 02 sensors. Simple, transfer the sensors to the new headers, no problem.

LG headers "used to" have no rear sensor provisions at all, and supplied a harness adapter, instructing you to move the rear 02 sensors to the front location, and connect to the front harness. This leaves you with the option of editing out rear 02 codes, or using 02 sims to prevent the MIL from appearing.

AFAIK, current LG systems are shipped with four 02 sensor bungs, allowing you to retain the use of all four stock sensors, but yet you might still need an extension to reconnect the front sensors to the harness....I don't know for sure.

As for removing ALL of the 02 sensors, yes, this can be done, and that is what my original reply concerned, since that is how the question was posed...and that is exactly how my car will be running this spring, with zero 02 sensors connected to the PCM. It takes z bit of tuning to pull that off, yes.

BlackZ06

Y2Kvert4me has it right ..... though I just wanted to point out O2 sims are no longer available. The feds have shut that avenue down. Removing the rear O2 sensors requires tuning or you have to live with codes and a CEL.

Bounty

I recently had a set of LG Streets installed on my 98 C5. The installer placed the rear O2 sensor's in the front bungs as that is what he had always done in the past.

Even after the dyno tune, the car would run rich at times and was throwing DIC codes which equated to "slow switching" between the O2's. We then re-installed the front O2's with proper extensions and all codes are now gone and the car runs much better...

AlisonC5

Great info, I was confused, I feel much better about the whole thing now.

I will be getting a system with cats and bungs for all (4) 02 sensors. so there should be no codes or problems hopefully.

Thanks for taking the time to explain it all!!!!