2013+ stangs. AFR stuck at 14.0??

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
This has happened on multiple occasions already. The AFR readout gets stuck at 14.0
It won't go up, it won't go down. I park the car, shut it off, restart i and then it finally kicks in and starts showing the AFR properly.
Did anyone else notice something like that on their displays?
Wtf is this all about??
Car drives normal when this happens, but i refuse to go WOT. Too worried lol.

I had the car out after winter storage since thursday afternoon and it already happened today once
Its freaking me the hell out. I'm starting to hate the damn lcd lol.
 

Shaun@AED

Well-Known Member
Joined
Jul 13, 2005
Messages
2,253
Location
CA
Happens when you have an O2 sensor problem. ECU defaults and ignores the O2 readings.

Or it is simply the O2's not fully warmed up. It can take up to 3 minutes for the O2's to warm up, during which time A/F reads 1.0 lambda.
 
Last edited:

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
This was definitely well past 3 mins though... :/

It always is actually...
 
Last edited:

scotmach

Well-Known Member
Established Member
Joined
Jan 23, 2005
Messages
2,185
Location
Connecticut
Another bad o2 sensor possibly Derek? Maybe starting it in cold weather introduced some moisture into one of the sensors?
 

me32

BEASTLY SHELBY GT500 TVS
Moderator
Premium Member
Joined
Sep 6, 2005
Messages
18,457
Location
CA,NorCal
Are the 02 placed in the top facing down. Cause there have bee. Lots of issues with long tubes and 02 placed on the side causing them to go bad
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
Nope, no extensions. Scott, this happened before i put the car away as well.
*sigh* always something...
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
Shaun, any advice on this issue?
Any way i can log things to see whats out of whack?
I doubt its as easy as a bad o2 sensor since the car runs normal, no stalling, no check engine light. Other than that lcd, there is no hint of any issues.
 

Shaun@AED

Well-Known Member
Joined
Jul 13, 2005
Messages
2,253
Location
CA
Shaun, any advice on this issue?
Any way i can log things to see whats out of whack?
I doubt its as easy as a bad o2 sensor since the car runs normal, no stalling, no check engine light. Other than that lcd, there is no hint of any issues.

My opinion is its the ECU not going Closed loop when the O2's are not warmed up. Longtube applications result in longer periods waiting for the O2's to warm up.
In which case it runs straight off the Maf curve. Unless Lambse is set at 1.0 all the time, your car is not running what the Air Fuel gauge is reading.

Obviously this can be verified with data logs. I can see in the logs what your dash gauge is reading.
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
I stand corrected.
Car died on the way back from work. And then a second time at the carwash after work.

Still no check engine lights

Edit:
I just went out to the car with my sct handheld. It found no codes.
 
Last edited:

snakebittengt

New Member
Joined
Feb 23, 2015
Messages
4
Location
Memphis
Mines doing this too. No codes or check engine light. Except mine tonight when started was at 20:1 for 5 minutes then started jumping up and down between 12-16:1w1while cruising at constant rpm for just a few minutes then pegged out again at 20:1. Im so confused. What did yours turn out to be
 
Last edited:

clc44

Active Member
Established Member
Joined
Dec 2, 2008
Messages
3,147
Location
Atlanta, Georgia
Interesting, I don't even leave it in the gauge. Maybe I should. I should probably datalog my car. Running vmp email tune. Everything feels good.
 

Bluegoat06

Cam Only LS2 Powered
Established Member
Joined
Feb 1, 2006
Messages
309
Location
RSM, CA
What are you guys using to see the AFR ?
The way I see it, if the car is running in close loop, an aftermarket WB is going to display stoich, unless you're reaching optimum power, at least from my interpretation from GM tuning, which in concept i'm using to tune my Stang :)

The 02 sensor feedback and fuel trims will always try to maintain stoich at idle and part throttle, then optimum power takes over when certain conditions are met, to give the engine a richer fuel (usually at WOT), or when the engine starts cold, etc.

What are your LTFT's displaying when the WB goes to 20% afr ?
 

clc44

Active Member
Established Member
Joined
Dec 2, 2008
Messages
3,147
Location
Atlanta, Georgia
Mine shows between 13.5 to 14.5while one and of and under slight acceleration. Think it's 12 or so when wot. Sound right?
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
I got myself a blue tooth obd2 dongle and the torque app on my phone.... aaaaand I found my problem...
Screenshot_2014-09-26-15-30-30_zps39vt2edq.png

Screenshot_2014-09-26-15-35-24_zpsf7yw1nxk.png
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
could be one of two things... either a completely bad o2 sensor... or since the headers move the sensor farther down stream of the exhaust, the sensor sent slightly delayed reading, the computer figured something is off and defaulted to one sensor only. I restarted the car after that code and the problem went away and so did the code.
 

snakebittengt

New Member
Joined
Feb 23, 2015
Messages
4
Location
Memphis
so I data logged the car today and it showed that both front o2 sensors were not even working. From what I can tell it looks like the o2 sensor are bad. Possibly from using o2 extensions exhaust leak or tune issues but more likely the extensions causing the issue
 

Nuar

Active Member
Established Member
Joined
Jan 4, 2009
Messages
1,774
Location
Connecticut
Yup, extensions have been known to cause nothing but problems. Removing them would be my first step to troubleshooting your issue.
 

Users who are viewing this thread



Top