How to Megasquirt your 3G Hemi

For those who are 'new' tuners and reading this thread to tune their cars, I ran into an interesting situation last night worth telling about.

I was experiencing a lean spike at 4,000 rpm. I mean, 16:1+ AFR. I couldn't figure out what it was until I looked at the MAP reading. Historically I've had the VE table with the left columns reading:
100
95
90
85
80
etc etc

I used to have the VE numbers the same in the 95 & 100 rows, but that was causing a rich issue at part throttle. Well I allowed tunerstudio to 'self tune' at part throttle, and it drastically reduced the VE number in the 95 cell.

Anyway, what I came to find out was that under full throttle, the MAP reading drops to 95 at 4000 rpm. So, the MAP reading under full throttle (95) and part throttle (close to 95?) was the same at 4000 rpm, so I either was lean at WOT (16:1+) or fat at part throttle (9.5:1 AFR).

My solution was to add rows:
100
98
95
93
90
85
80
etc etc

Anyway, that helped. That allowed me to put the WOT VE in the 95, 98, 100 cells for 4000 rpm, and put something more appropriate in the 93 cell. I've still got a little fat issue at one small throttle position, but I'm not sure I could improve on this tune unless I stepped away from speed density.

So- lesson for the day:
If you've got a lean or fat issue you can't figure out at WOT, check the MAP reading to make sure it's referencing the cell you think it is!