Yes, there are three sensors on the waterpump/thermostat housing - one for the ECU, one for the fan relay, and one for the climate control. I accidently unplugged the ECU temp sensor on my '93. It was difficult to start cold, but ran fine warm. I'm assuming that without any engine temperature data, the ECU didn't deliver any cold enrichment, hence the no/difficult start. It would start if you gave it some throttle.

BTW, I think your voltage regulator looks normal. A few minutes of 14+ to charge the battery following a start, then dropping into the 13 range is completely normal.

- JimY