I've had a long (not really steep) learning curve getting better at EFI - wiring, component selection, ECU issues, injector issues, etc. One of those issues was the use of Innovate LC-2 02 controllers.
I used one controller for the first couple of years and it worked fine....when it was on, but sometimes it wouldn't cycle on and could never tell without having my laptop with me - and on. I didn't want a large gauge on the dash and I didn't want to lose my clock, at the time, so I kept, passively, looking for a gauge solution that would simply help me know the the 02 controller was on and working.
In the mean time, I decided to go to dual 02 sensors (switched to AEM) because I "thought" that I had an issue with an injector that I couldn't diagnose. I was wrong about the injector, but I did get the two 02 controllers installed and started to experiment with tuning.
I also found a gauge, enter Zada-Tech. They didn't have a dual AFR at first, but they quickly whipped one out and within a couple of weeks I was displaying both AFRs in the dash.
https://zada-tech.com/products/oled-multi-gauges/oled-digital-dual-afr-air-fuel-ratio-multi-gauge This gauge allowed me to tie straight into the 0~5v output of the 02 sensors and because of the small form factor, I was able to design/print a small bezel that allowed me to put it right in the dash in place of the existing Seat Belt light (super useful).
Back to tuning... I've spent many a minute bent over ITBs trying to sync side to side at idle and also side to side at some random RPM that I would use vise grips to hold the throttle open to achieve. I've used the handy dandy carburetor sync tool, I've used a cluster of vacuum gauges ported to the manifolds, and I've used my ear. This all works fine at idle, but doing this under load sucks and under load is ALWAYS different than at idle due to any linkage slop (they all have some amount of slop).
So, not any more. I learned I could use the AFR from bank to bank to quickly sync at idle and then log data to tune off idle. I switched the sensors from side to side to confirm calibration - just to double check.
While, it's not perfect, and nothing is, it is SUCH a game change for syncing these cantankerous wonders of EFI.
Here you can see the result. Again, not perfect, as there are other things to tweak (AE), but it sure helped.
Back to Zada Tech, this has been a HUGE benefit, as well. Now I can quickly see that both controllers are on and working and I can quickly check to see if the banks are sync'd and that there are no major injector faults causing AFR issues. And it pretty stealthy in the dash.
Happy Days on the AFR front....