Scanmaster and powerlogger reading different than gauges

[TurboTnZ06]

At last nights test n tune, my scanmaster finally started showing all the different extended properties. I noticed the scanmaster reads 4.5psi when the manual boost/vac gauge reads 0. The wideband reading on the scanmaster is 0.75 higher (leaner) than the AEM gauge. All the way down the track I saw 10.0 on the AEM gauge and the powerlogger said 10.74-10.76 all the way. I saw 17-18 psi on the manual boost gauge and powerlogger says 22 psi. I am running alkycontrol. Could the T into the 3 bar MAP from the alkycontrol increase the reference signal voltage to the MAP? Are GM Map sensors accurate? This could explain my rich condition even though power logger says otherwise. My spark plugs look dull, not black. My wide band is blacker than I'd like to see. My battery voltage is showing 13.2 or so and I do NOT run a voltage booster.

 

[TurboTnZ06]

It looks like the powerlogger UI has a feature to offset the voltages, guess I could tweak that. I also keyed on and now the scanmaster says bst 0 instead of 4.5 like it did last night, but the car wasn't running. I'll play around with it some more and see what's up.

 

[TurboTnZ06]

Drove it for lunch, it was acting crazy, 4.0 #'s bst on the scanmaster and 0psi on the autometer gauge. Then went back out to the car and it was right in line with the gauge. I pulled the vac line, no crack,s leaks nothing, plugged it back in, same readings. Electrical problems usually aren't intermittent, they either work or don't work. Going to test the stock MAP sensor tonight.