
So what about an electronic one, with some decent adjustment for set point and differential ? Easy.
But I didn't want to add another sensor so why not tap into the EFI block sensor ? To cut a long story short its not really practical.
Issues :
The signal is around 400mV at operating temp with only a few mV change over the temperature area of interest - so getting a small differential was proving very difficult.
And the big one - the reference voltage applied to the sensor is not stable enough - it fluctuates by a few tens of mV with changes in battery / alternator voltage causing unpredictable cut in and out.
So don't waste you time - just add a separate sensor.
For the tech minded the EFI system really only uses the block temp sensor for cold start and warmup - once its up to temp its pretty well ignored which explains the low sensitivity at operating temp.
The temp gauge sensor is also no good as the system works on a different principle.