When selecting Injection Type Custom, where do you define the Injector Impedance?
After selecting Fuel System/Injection Type Custom, I select Configure Injector Sets and enter the following.
1 Injector set, Sequential
8 injectors
System Type Custom
Flow rate 275 lb/hr
Rated Injector Pressure 43.5 psi
Actual System Pressure 43.5 psi
Min Injector Opening Time 1.5 ms
Driver Setup

When you go "back" and select Injection type multi-port or TBI, whatever was configured previously on that page for injector set is changed to High Impedance, 9999.9 lb/hr, 999.9 psi. This seems to cause problems syncing the custom config with the ECU which requires low impedance injectors set.