MAP sensors and such

[ChrisCNC]

Okay, I must be really tired...
what kinda freak thinks about MAP sensors all day?

Some comments made by Cody got me thinking about the MAP sensor on my truck, 2003, 7.3L Ford Diesel.

Since these sensors are only accurate to about 23 psi, what happens when someone upgrades the turbo? Pretty much any turbo upgrade will get you over the 23 psi point (why else upgrade?), won't the 38R's that are so popular now putting out 30 psi pretty easily? Does this mean that unless the MAP sensor is upgraded somehow, that the engine is actually running lean? Are there other programming points of interest that are available that will get you there instead of relying on MAP sensor readings?

And if one did upgrade the MAP sensor, you could no longer return to your stock tune, correct? This may not be an issue unless you're running something like the Gryphon/Edge unit where you're supposed to return to stock before you download anything. Doing so with an upgraded MAP sensor would effectively disable the engine.

Are the older trucks, like mine (2003), using a MAP sensor that is a dual cylinder pressure transducer? or are they running the newer MEMs Style Pressure Sensors?

I read somewhere that the PCM used to take a MAP reading before the engine was started to get an "atmospheric" base reading to compare post start MAP readings against. If this were true, wouldn't it be useful to stop the vehicle part way up a good climb so the MAP sensor could readjust itself for altitude? That be a good one, "...really officer, I had to pull over so my MAP sensor could recalculate for the current barometric pressure..."
I guess it work as well as any other excuse.

I know, I know...get a life...