hand calculated or reported to your dash?
reason I ask: one of the old and clumsy ways to get more power was to simply get more fuel to your cylinders by altering the computers reading of rail pressure.. if the rail pressure is 20kpsi, but the computer is understanding 15kpsi instead- it would extend the duty cycle of the injector brief enough to make up the additional volume.. higher pressure means more fuel injected than a lower pressure through the same open time frame; either the duty cycle, (or how long it's open) can be extended, or the pressure can be upped- one of or both of the two gets more fuel to your cylinder..
the fuel rail pressure sensor is somehow and directly connected to the PCM's interpretation of how much fuel you're consuming.. I only know this because I lost a frp on a long highway haul.. hand calculated showed I was getting 17ish MPG's, but according to the lie-o-meter in my information center, I was getting 30+MPG's with my outright failed FRP sensor..
if you're using a programmer that doesn't comprehensively alter multiple tables instead of just intercepting and re-figuring that one, you are making your truck lie to you about it's true consumption..
Last edited by drewactual; 02-11-2013 at 09:36 AM.