Today I ran a cold start test using a 13.7 volt source to power the Motronic and fuel pump/injectors. I found a very interesting result regarding dwell time. Keep in mind that I have new stick coils installed.
Before getting to today's result, yesterday when I cold-started with a stand-alone battery whose voltage was 11.7 volts powering fuel pump/injectors and Motronic, the after-start stick coil dwell was about 1.7 mS.
Today (same config) using a 13.7 volt source--my car's battery with the alternator running--the dwell time was 0.5 mS, that's 1/3 of the dwell compared to using the 11.7 volt source. And the start was not as robust as when I used the 11.7 volt source.
The difference is that the coils had 13.7 volts on them today (note to self: check voltage on the other side of the key which powers the sticks) and the Motronic read my second battery also 13.7. Yesterday, the Motronic read the second battery at 11.7 but the coils had actually 13.7V. So the combination of a high voltage at the sticks but the Motronic thinking it was a low voltage leading to longer dwell produced a spark that better combused the mixture.
I'm floored! Who would have guessed that the Motronic sets dwell partly based on battery voltage? And that a stronger spark would lead to a better start!!