No no.... when I turn the key the engine spins normally and strong.... for 6 or 7 SECONDS, then stops cranking. I can repeat this over and over.... the battery is very strong. The engine just refuses to fire... like not one pop of one cylinder at all.... just cranks for 6 or 7 seconds then times out.

In discovering this problem, I now realize that Mercedes Benz engineering logic let's you crank the engine for those few seconds, but then they have an automatic timeout for starter motor engagement, until you wind the key backwards and start it again. I had never run into this timeout before, as the car ALWAYS started within a second of cranking starter engagement.