Doesent the ecm display timing via crank sensor? Its done through software, no? The spark energy is there i would assume,and engine runs.
Ther is no logical reason the light shouldnt work unless spark is really weak.
Yes, the ECU does display the timing. But for the display to be correct, The Base timing is temporarily set to a fixed 20* in the setup and then checked on the timing tab to make sure it is correct and matches.
The engine starts and runs, just need to verify the timing is correct before proceeding with tuning.
