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AFR Monitor FAQs

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Q: AFR CMD Doesn't make the commanded fuel leaner than stoich (14.7:1 gasoline)
 

AFR CMD is not the actual 'out the door' commanded AFR. We are in the process of tracking down all modifiers in the near future, there are other trims and scalars attached to it. You also won't be able to use the fuel target in Fuel Low Det to get a learner than stoich commanded target currently. There are other limits or modifiers which are not exposed which must control this functionality. 

 
Q: The "a/f ratio B1" is reading a point richer than the dyno wideband I use. "A/f ratio (depreciated) old" matched what the dyno wideband read almost perfectly.
 
Using a tail pipe sniffing wideband will yield a leaner than actual result normally and I'm not surprised it does not match the AFR monitor from the ECU. Both of the AFR monitors from before were using the wrong scaling.. The actual scaling which being used now is known to be 100% correct. AFR (old) was actually a guess at a scaling derived from a tail pipe wideband, which explains why it is so close to what you are seeing now. 
 
Keep in mind that this new AFR scaling is known to be correct but is dependent on the sensors in the exhaust reading correctly. Due to their position in the exhaust stream and the amount of heat they do see it is possible for there to be variances in the actual AFR from what the sensors will read and send to the ECU. This is not a issue with the sensors being read incorrectly, but an error in the measuring capability of the sensors themselves. 
 
In any event, the STFT and LTFT (combined as A/F alpha) has not changed, so if you want to compare your old AFR monitor to the new AFR monitor to get acclimated it would be a good idea, since those monitors with a z in front of them will be leaving in a future software release. 
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