Long Tubes making me run rich?

Just installed long tubes and a aero muffler. i have been watching my fuel trims since install and have noticed that my short term fuel trim is always pretty much in the negative i would expect it to be able to compensate for more flow and adjust for it has anybody ran into this before ?

 

how are you monitoring your short term fuel trim?

 

Short term is not what you want to look at for your situation. You want to look at long term. Short term fuel trim is a continuous changing and compensating number that can be affected by so many simple and minute things, that you can't really use it for long term use. You could drive through a low lying area with a patch of cold air and see your fuel trim fluctuate for just a second.

 

How far in the negative? And did you monitor it prior to the headers?

Like Bama said, best to monitor LTFT, but you'll want to reset the adaptives first if you didn't disconnect the battery on the install.

 

My LT is staying around 5.0 and ST is staying in the negitive i know that it is supposed to fluctuate between positive and negative but it seems to stay in the neg meaning its trying to lean it out. I watched it before i slapped them on and it seemed normal. Im using my ultra gauge while driving and a scan tool while parked.

 

How many miles have you put on it since the install? Generally, you want to give the LT several hundred miles to adapt. As long as ST is the opposite of LT, it will eventually get close to 0. It will never be 0, but as long as the net between LT and ST is close to 0, you're fine.

 

I have done somewhere between 500 to 800 miles.Thats what im concerned about the fact that it is not leaning out and its just staying in the lean command for the most part. I wanna do the maf calibrator but thats only going to help me in open loop and this is happening during closed and open loop driving and i could just be tripping out over nothing just trying to see what everybody else has ran into

 

That is some unusual numbers. If the STFT is ALWAYS in the negative, but the LTFT is still positive, then something else is wrong.

 

Ya thats what I have been thinking could a exhaust leak be messing with the O2 and fooling it into thinking it's running lean cause of the more air ? If that makes any sense if it dose that may be y it's running rich but I don't think there is a leak and if there is it would be minor

 

I would try disconnecting the battery, then see what the LT starts off with in the beginning.

 

Gunna try that here in a bit and see what the lt is at

 

Personally I think you are spending time that does not need to be spent. If your fuel trims are small single digits, and they are netting out to 0, or close to zero, you are fine. If the numbers start going up, or the net is double digit, then start working it. Otherwise enjoy.....

 

Gotcha thanks for the help guys just gunna keep a eye on it