I assume if your air/fuel ratio isn't in range it will throw a light. I know people are worried about how lean they are running after they install a supercharger and run off to a dyno/tune shop. But if it was off wouldn't it throw an engine light?

 

No for 2 reasons:
1. unless you are at WOT - then you are in closed loop mode and barring radical mods the PCM can and will maintain correct A/F
2. These engines, particularly when FI'd are very sensitive to detonation and detonation generally can and will occur long before it is far enough out of A/F goodness range for a code...

Short version - don't trust the light and you won't see it until it is too late (i.e. WOT at 6K RPM and piston parts flying around)...

P.S. I am not using JDM's tunes, but their results speak for themselves... They have pushed a LOT of HP through a stock bottom without issue, so while you should take a look at your WOT A/F after a hard run I would not lose a lot of sleep over it - they seem to know what they are doing...

 

At least the last part of your response calmed me down lol. That first part, wow.

 

Sorry, did not mean to scare you, but idiot lights on normal cars are only useful after the fact. Add FI to the mix and they really become useless...

A/F is particularly problematic as I mentioned since at WOT - it is no longer in a closed loop system and you are now at the mercy of the tuner's best guess... (which in JDM's case is a good one)...