More power with less fuel???

[Philip Lochner]

I have over the last two days been tuning my '95 Land Rover Discovery with a 4.6L engine now fully managed by MS-II.
 
Tonight I went up a hill with 50% throttle in 5th with AFR @ 13.5 whereas before (with original ECU) I could not go up that same hill with WOT (AFR @ 12).  Timing can not play a role as before I had MS-II doing the timing anyway. The original ECU was doing the FI at that time but it was running the engine substantially more rich.
 
Is this possible? Or is something else going on here?
 
Kind regards
Philip
MS-II/2.35/V3/MT 2.25

Posted by email.

[zguy36]

That is exactly it... 12:1 afr is really rich for only 50% throttle. Too much fuel doesn't give more power.