Starts OK when warm, but startup problems when cold
This can be a LOT of things. Describe your setup. Besides the basic things on IssueReports (firmware, config, wirings, etc...), also
- measure DC voltage on VR input
- maybe pullup-resistor adjustment is needed (like a stronger pullup) ?
- elaborate on injector size
- compare starting pulsewidth to the runnig pulsewidth (at low RPM, near 100 kPa)
Also stumbles during cruise
At high power it kinda works, but not perfect.
RPM, ignition advance, injection pulsewidth stays constant, it still stumbles.
This can be a few things. Describe your setup. Besides the basic things on IssueReports (firmware, config, wirings, etc...), also
- make some logs and take note where you experience the problem
- what is the current consumption of the ignition coils (at known RPM and actual dwell times) ?
- maybe dwell adjustment needed. Too high dwell can break the coils and or the power ignition outputs
- do you know fuel pressure ?