Robbie:

The one on the STB side (down below the starter) is the Digital Pitot (speed) Sensor.

The one mounted at the rear (with GRAY tubing) is the Water Pressure Sensor. As it came from the factory, there was a "tee" right below the PORT SIDE fuel rail, with gray tubing running forward (and a plug in the adapter end of the tube). This may have been removed previously.

Tee's, adapters, etc. are readily available to allow you to "tap in" to this water pressure circuit. Contact our Parts Department for details.