I noticed that after my car has been down for 2 months because of my lack of interest in changing out it's alternator, I finally got a new one in there but when the car is not even on my PFC reads -54 vacuum. Im thinking I need to recalibrate my MAP sensor but how? I also have a 3 bar under the hood, just not hooked up and never calibrated. Can the calibration of either MAP sensor be done through the Commander or do I have to use a Datalogit, which I do not own?


Also any idea as to why the sudden misreading of the MAP sensor after an alternator change?

Thanks,
Jason

 

You probably just never noticed it, the PFC's stock calibration is a little off and doesn't show 0 at engine off.

Dale

 

The previous map value was exactly 0.0 when the engine was off but in the on key possition. Even stranger is my Pettit boost controller reads -01psi when off when it also read 00. Now I'm beginning to think I may have a different problem all together.
I took the car out for a short drive last night and I noticed the voltage would drop to 11.8 v when in gear at a stop light but would jump to over 13v when driving. Could a ground problem be causing these weird issues? Where to start?

 

You forgot that the DFW area is higher altitude than Houston.
Silly Jason!