Power fc boost reading is -48mmhg when car is not started
 

my power fc is reading a -48mmhg when the car isnt even started, is there a way to ajust this. Will it affect performance. or will it hurt anything . any comments or suggestions apprecitated

You're seeing atmospheric pressure It won't hurt anything. Means you live above sea level (atmospheric pressure decreases with elevation). It would read 0 at sea level. It can be recalibrated using datalogit but there's no need.

Mine usually reads about -18 living near sea level.

Jack

Yup, normal. Mine currently reads -46 in the Tennessee Valley area of Alabama.

True he may live above sea level but that is a wrong answer.

When Apexi created the PFC, they never calibrated a stock map sensor to the internal programming. Thus the conversion from MAP sensor (PIM) voltage to PIM ABS and boost(kg/ccm^2) has always been lower then the real world.

This has been discussed many times since we first received our PFCs back in 1999.
How to calibrate your sensor has also been discussed here.