I have taken out an other tooth to make it a 36-2 wheel. Changed the Wheel Decoder settings and checked the timing again.
But the problem is still the same.
Most enigine starts are fine. But often at cold starts or some times when the engine is warm, I get a back fire or starter kick back.
Also the "hold ignition" setting doesn't seem to work many times. Than the engine fires at the first turn of the key instead of holding for 4 cycles.
To me this looks like the MS is getting false triggers for some reason. And that is messing things up.
I'm going to try it with the starter disconnected from the rest of the car and start it with a 2nd battery. That should rule out noise from the starter.