timjuice83

I have an 03 mach 1 that I did some exhaust work on now I've got a CEL. Now this is a little bit backwards from what usually happens so I'm having trouble finding information about it. I bought my car with no cats, no mufflers, just an x pipe and then over axle pipes and out the back. Everything ran great but it's completely illegal here so I decided to make it more legal, not to mention it was WAY to loud and pretty annoying to drive after a while. I put on LT headers, high flow catted x pipe, and a cat back system. Car still runs great but I now have a CEL after adding the cats. Had the codes shot and it's for the O2 sensors so.... Any ideas on what I need to do to fix it? I'm thinking I need to get it tuned, but any additional info would be greatly appreciated. TIA

jrp1588

What's the code?

uberstang1

If its the front o2s the computer might be tripping because they are moved farther downstream in the exhaust system.

timjuice83

4 codes for it:
P1151
P1152
P0153
P0133

Makes sense that they are moved further downstream so... Any suggestions for fixing it? I am planning on buying a tuner with some custom tunes, what's the chances that fixes it?

jrp1588

Weird, from the quick google search I did, one of those is a lean code and one is a rich code. Seems like I read a tuner is the solution for long tubes throwing codes, not positive though, still new at this engine.

timjuice83

Ok after some more research it's because the fron to2 sensors are further down the line thus they aren't heating up quickly. I called the bama tuning guys who assured me that if I puchase a tuner from them at AM their custom tune would fix my problem. Hopefully this 380 bucks works!

Blackvenom01

ya a tune will work unless your O2 sensors are shot you will soon find out

uberstang1

Tune and or new o2s.

cliffyk

There is a table in the tune, O2 transport delay, that defines the time in which changes in air/fuel ratio made by the PCM should be "seen" at the O2 sensors, dependent on load and RPM. As most long tube headers move the sensors further away from the exhaust ports the values in this table must be increased to make the PCM happy.

Here are the stock values, typically bumping them by 15-20% will correct the problem:

uberstang1

Cliff you blow my mind with your highly descriptive knowledge sometimes.