I recently acquired a bluetooth OBDII device which I'm using with Torque for Android. About a week ago I installed the upper and lower pulleys for Eurotoys. I've been monitoring the Air fuel ratio (measured) and its constantly reading between 14-15+. Should I be concerned with running way lean or does Torque not provide an accurate AFR? I'm no expert at this kind of stuff. Since the pulley install, I've been patiently waiting (200 miles) for this number to drop, assuming the ECU would adapt to the increased airflow. I'm eager to do some WOT runs but this AFR reading has me a bit nervous.

 

At cruise when the care is warmed up that would be normal.

14.7 is "ideal" for having the right amount of air to consume all of the fuel and modern cars generally run a little lean of that at low load conditions to improve emissions.

The right number to look at is the fuel trims. if the long term trims are stabilized and the the STFT is bouncing around zero on a level road at constant speed, then the adaptation is done.

 

Thanks, Charlie. I'll keep an eye on my STFT. I was under the impression that the A/F ratio for the boosted XKR platform should be a tad on the rich side.

Edit: I've seen other members that have posted their A/F ratios of 11.7, 12.1, 13.0 etc. Mine never dips below 14.2...assuming that Torque is reading accurately.

 

In the thread posted below, WaterDragon states that his "A/F was 11.7 :1" To which Avos replied, "The a/f ratio is also relatively lean for your car model".

Is Torque reading the correct measurements or am I looking at the wrong thing entirely? I just went for a drive and at 3/4 throttle I was seeing 14.5:1-14.9:1.

https://www.jaguarforums.com/forum/j...-torque-75435/

 

They are talking about the AFR at WOT as measured by an external sensor. OBD stops transmitting the AFR data when you mash the throttle, so what you see is likely just garbage data.

You can figure out the AFR from the analog output of the O2 sensor, but as far as I know you need the WDS/SDD to log the current output and then you have to do the conversion to AFR after the fact.

 

Ahh ok. Makes sense. Thanks