Is there any way to verify that the CZ unit is doing anything besides looking at your AFR?

I have a used CZ unit, a CZ USB cable, and a CanScan. I loaded the Stage 2 map on the CZ and went for a drive. Datalogged it, came back, and I'm still hitting 11:1 AFR @ 6500 RPM, just like I was before the CZ.

I took out 18% more fuel at 6500 (and a bunch of other adjustments). Did another run, still hit 11:1 at 6500. The two AFR vs RPM graphs look almost identical. The car doesn't feel any different. As far as I can tell, it isn't doing anything at all. I have 31% out at 6500 and 44% out at 7200 yet my AFR never goes above 12.5 between 6K and 8K.

I do have the switch "on," I have calibrated my throttle, and I am getting a slight stumble at idle, so I know it's there ;)

Am I missing something?

to verify its working you should be able to log the MAF and see the differences

Did you buy it used? All CZ units originally came so that the rpm's are in a 1/2 scale and positive numbers increase your afr... there are various ways that people have "improved them" (not really, but...) and rewired them to make the rpms in full scale and lower numbers to increase afr. If this is the case, you should be able to run the unit in the car with the map trace function and see what the hell its doing (will highlight the cell of the map its in).


... the stumble at idle can be cured by removing the extra timing thrown in at idle in the ignition map