PowerOverFC

Ive found that my map sensor is off by -2" (Im NA, and it seems to be pretty even throughout). Is there anyway to calibrate the onboard map sensor?

Chris Ng

I wonder what type of map sensor the microtech uses..
You are not the only person who has a miscalibrated map sensor.. Rx7_turbo2 's map sensor reads -5" off throughout..

No7Yet

My own personal theory is that the Microtech sensor is, in fact, correct. When one does mass air calculations, the relative pressure isn't used; absolute pressure is. A good example is that since the engine is sucking in less air in Denver at 16inHg relative versus an engine in Miami at 16inHg relative, it'll need less fuel to maintain a proper AFR. This (in my estimation) is the reason that the LT doesn't have a barometric correction like some other EMSes. The best I can figure, an arbitrary value was chosen as a "zero" and relative numbers were displayed because that's what everyone expects.

My $0.02.

Brandon
BR7 Racing

Piranha

Yep, it's based on density, which is correct. Remember, you're measuring pressure, and 0 is actually sea level, which is actually 1 bar which is 29.92 inHg. If it was thinking you were at sea level at whatever altitude you're at, the computer would think you had more air going in than really was.

Josepi

So what's a fluxuating from 0-02" vac when the car isn't even running mean?

No7Yet

That means that the sensor is hovering right on the resistance value where the ECU switches from 0" to 2" on its display. You could conceivably do the same thing with a mityvac and a lot of patience.

Brandon
BR7 Racing