MAP sensor that measures the vacuum/boost* of the intake air. that signal, combined with the IAT sensor let's the computer figure out approximate air density and helps it adjust the fuel mixture right?...well would barometric pressure make your car still bog a little depending upon where you lived and what the barometric pressure was in that region?

Reason I am asking is many of you know I have had a problem with my cars vac-boost transition. I recently went to NOPI in ATL, and I live in VA Beach, VA which is right at sea level. On the trip down the vac-boost transition was perfect...no bogging or anything of the kind.

So I was just wondering if living at sea level would cause this to occur...and yes I am running the ML...and yes I have cleaned it multiple times. See one I got back from ATL and back to VA it started bogging again.

Just a theory in my quest to find out WTF is wrong with that transition.

Good theory IMO.

What the hell else could it possibly be?

I think you need to move to ATL for your car to boost good :P

try a quality FCD with the ML and see if it solves the problem.

That is my plan...but that still will not explain why it was fine from NC clear to GA and back. Once I got near the tip of NC it started back up again. Makes no sense!

Originally posted by Aggression
That is my plan...but that still will not explain why it was fine from NC clear to GA and back. Once I got near the tip of NC it started back up again. Makes no sense!

Yes it does make sense dood. Obviousley the atmospheric pressure is different at sea level. It makes total sense.

My boost gauge reads like 1.5 psi with the car off :P But when I go 3 hours away it reads back to 0psi. Stupid elevation changes :P

Originally posted by Blizare
Yes it does make sense dood. Obviousley the atmospheric pressure is different at sea level. It makes total sense.

Yeah, but you are going to be crossing that point regardless of what valley or mountian you are on. The atmospheric pressure just determines at what point you are actually in boost pressure and at what point you are in vacuum.

That missing link is gonna close (should) when the pressure in the manifold goes above the pressure outside. That could be at 920 millibars (up a few thousand feet) instead of 1010 millibars (roughly sea level)

If the missing link closes when you are at altitude, then your MAP sensor won't go above, say, 4.30 volts instead of 4.60 volts at sea level. That extra wiggle room may explain why you don't get any fuel cut.

I am going to try my friends ML and if that doesn't change it...I will just have to do the VC on top of my ML for an added FCD.

ner947, your logic is exactly what I have been writing down on paper and researching for myself.

I have been really getting into this whole BP and theories of how it can effect our boost pressures.

Thanks guys! I will let you know the outcome of trying someone elses ML and/or VC.