You can not use A4 and A5 for the new adjustment pots. They are common with the SDA and SCL pins for the i2c lcd.
I have changed them to A2 and A1 and the code does not crash. One other correction is that pulseWidth needs a non zero value, and I have set it to 10 degrees. There was also an incorrect arrangement of the if/else on the rpm mapping with the charge pulses which I have corrected.
tester_revision_2019_B.ino (9.94 KB)