Port Injection requires a significantly richer AFR target than Direct Injection under load. Where you might run 12.3 AFR on DI you would want to run closer to 11.3 on PI. Make sure you or your tuner are familiar and experienced with tuning port injection engines or engine damage may occur due to improper tuning.
Direct Injection provides more knock resistance than port injection so be careful when running on lower octane fuels and high boost. In our testing with ethanol blends we did not need to reduce ignition timing at all when compared to direct injection.
Port injection may require a 10-20% increase on cold-start fueling for a faster engine start time.
Before tuning any fuel mass related items it is ideal to start on pump gas where a known fuel scalar results in a +-10% total trim (STFT + LTFT) at fully warmed up idle.
After flashing the vehicle for the first time, reset the lambda regulation adaptations.
Disable long term fuel trims (LTFT).
Using our base table values and the injector characterization data from the injector manufacture the idle should be quite close. Start logging before starting the engine and allow the engine to fully warm up to 208 F with no accelerator pedal input during this period of time. This log should show STFT +-10% throughout the majority of the log. It is normal to see higher negative STFT’s immediately post engine startup.