Short term fuel trim?

[96cobracoupe]

When I am logging my short term my 02's are showing stuck at 1.0. at WOT
I have a 12 model with low miles are people having any trouble with 02's going bad? Or could there be something else going on?

 

[fbody83]

When you go WOT, your car should go into open loop which no longer uses the short term fuel trims for fueling. Instead it uses the fuel you're commanding in the tune and in your logs your short term fuel trims during WOT should show this commanded fueling (in lambda).

If they're showing 1.0 and you're in open loop that's bad, because it means you're commanding an AFR of 14.7 at WOT.

 

[stang910]

When I am logging my short term my 02's are showing stuck at 1.0. at WOT
I have a 12 model with low miles are people having any trouble with 02's going bad? Or could there be something else going on?

Your laptop might be dropping out the STFT pid at WOT. Try to datalog only the STFT's and see if you see any difference. Also are you sure it's not the LTFT's that are going to 1.0? If so that is normal.

When you go WOT, your car should go into open loop which no longer uses the short term fuel trims for fueling. Instead it uses the fuel you're commanding in the tune and in your logs your short term fuel trims during WOT should show this commanded fueling (in lambda).

If they're showing 1.0 and you're in open loop that's bad, because it means you're commanding an AFR of 14.7 at WOT.

The copperhead ECU does things differently. It uses STFT's to correct the AFR at WOT. 1.00 is target AFR and you datalog lambse to see the commanded.

 

[96cobracoupe]

At idle on closed loop should the numbers be fluctuating?

 

[96cobracoupe]

After I data logged I plugged my aeroforce back up and the AFR was normal at WOT so idk that's why I am confused on what's going on

 

[MickeyD]

For the 2011+ Mustangs they have factory wide bands, while monitoring the STFT and LTFT is good i would also suggest selecting to record and monitor the Labmse B1 and B2 as well as the Measured AFR B1 and B2. This will give you a better idea of what is going on.

It is possible that an O2 sensor isn't functioning properly but typically if that was the case you would be getting a CEL or drivability issues.

 

[96cobracoupe]

Yea I just logged it measured AFR 1 is reading and 2 is a 2.0 Across the board not functioning what is odd is that when I plug my aeroforce back up it reads both banks of AFR

 

[MickeyD]

What tuner are you using? The reason I ask is if the tuner is in need of an update it can cause it to not read things properly and that may be the case here.

 

[96cobracoupe]

I just updated it last night I thought the same thing

 

[96cobracoupe]

Sct

 

[MickeyD]

OK, if you have custom tunes that you are running I would try reloading them onto the device and then onto the Mustang. Also if you are running custom tunes I would contact your tuner to check them out or if its just the preloaded tuned contact SCT directly as something is off.

 

[96cobracoupe]

Could the 02 be bad the car only has 11k on it, I have reloaded the tune and done all the troubleshooting logged with my tuner and everything so I am leaning toward a faulty o2 but its not throwing a check engine

 

[MickeyD]

its possible the O2's are going bad. Is this an SCT preloaded tune or a custom tune? Also what are your mods?

 

[96cobracoupe]

Custom tune
Mods: 13 Tvs 10% lower, dual 65 tb,72's and BAP also JLT 127 afco dual fan

 

[MickeyD]

I would have the tune checked out as well as the O2's with a set-up like that i wouldn't risk it. I also just PM'ed you some additional information.