I am currently swapping a 88 NA engine into my 96 Miata. I am using s MS3 that i previously used for the Miata and am now adapting the wiring to the 13b engine components. I am running into an issue where I am not getting an rpm signal when I crank the car. Though when i took the CAS out, spun it with a piece of rubber hose on a drill; then am i able to see rpm on the laptop. Though the rpm only shows up approximately after 500 rpm. If the drill is spinning the CAS too slow, there is no rpm signal. I don't understand why its only picking on the rpm after the CAS is past a certain speed. I've already adjusted the R56 potentiometer all the way counter clockwise and still cant pick up an rpm signal when cranking. So basically the problem is that I'm only getting a rpm signal when the CAS speeds after enough; which it cant speed fast enough with cranking of the starter. Below the wiring of the CAS I used and my ignition settings. Any help with be appreciated thanks

 

I was able to fix this problem by running cleaner sensor grounds to the megasquirt and adjusting the vr conditioners in the ecu all the way counter clockwise.