Hello everybody. I have a 21 mustang gt 5.0 that i've been playing with tuning on for about 4 months. Tune runs strong here at the bristol dragstrip on e85 and feels good on 93 octane as well. My question/concern is with the afr readout on the dash. I have had 93 octane in the car for the last 3 tanks of gas now, car runs great, no lack of power that I feel, no bucking, shaking or jerking. Runs really strong. My issue is the afr readout. It's hovering at 12.4-12.6 at idle. WOT can dip as low as 10.5. Now reading my afr values in lambda while data logging they show to be right on , .80-.82 at wot. I've been chasing this issue for a couple of weeks now and I am curious to know am I even chasing a real issue or am I fine? KAm reset has been done, as soon as the reset is done the values on the dash read perfect, 14.3-14.7 @ idle and 11.9- 12.1 at WOT. They slowly decrease to rich values as the LTFT start learning. my bank 1 and bank 2 LTFT are both around -10% after a half tank of gas. I've monitored 02 voltages thinking maybe there was an 02 sensor that was biased or hanging up and they all seem to be reading and reacting correctly. I've checked the maf sensor and checked the intake for leaks and all checks out and appears to be fine. Any help or insight would be appreciated. Attached is the log file from the drive last night . Thanks for the help guys.
post your tune file. everyone can help you more if they can look over your tune. i understand if you don't want to do that but you can get good info by doing so. lots of knowledge on this forum.
Because of the way alcohol content is inferred, it also ends soaking up LTFT and skews the displayed AFR on the cluster.
The only thing you can do is correct your fueling to eliminate the LTFT adjustment.
I've also heard that you can change the as built data to display lambda on the cluster, but I haven't had time to look into that.
Thanks for the reply. I'll have too look into this. I've been curious to know if you can change to lambda. That would be awesome. Would you happen to know what effects cam timing have on the air flow into the engine ?
you said it runs great on E85 so does it have a flex fuel tune in it?
if so, and the airflow models (MAF/SD) are inaccurate, when you run 93 E10, as seishuku mentioned, the flex tune bakes the fuel trims into your stoich afr.
put a 93 only tune in it and run 93 only and see what your fuel trims are. the only reason it would idle at 12 is if you are running a flex tune or you're in open loop and your airflow model is wrong.
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