Hi guys,

When grounding a hall effect sensor is it better to ground it to the ecu sensor ground pin or to the battery negative?

I normally use the sensor ground, but I would refer to the ECU documentation to make sure that's what they suggest for your ECU.

Most ECU manufacturers recommend to ground frequency-based sensors to the chassis, or your star earth point. Wherever you ground your injectors is probably a good spot. You definitely don't want to use the sensor ground, as the high frequency is likely to be a source of noise on the rest of the sensors.