Just wanted to correct something I said above, that the speed sensor is 6X the frequency of the ref sensor. That was a wrong statement. From the ref sensor I figured out the starter motor rpm is about 180 rpm or 3 per second. The output from the speed sensor is shown below, at 1 cycle every 4mS or 250 cycles/sec. This is pretty crude math but that would say the speed sensor is giving a pulse every 84th of a revolution and I looked closer at Bentley and seems it's providing a pulse every tooth.
Mike
