Yep it would make a difference, deffo needs to be attached to the common sensor ground pin for the ecu.

The pressure sensor gets wired into the 16pin AMP connector on the back of the MXL, I used Analog Channel 1 as my oil pressure input, so the white wire on the sensor goes to pin 8 (Analog Channel 1), the red wire goes to pin 6 (V Ref), and the black wire goes to pin 7 (Analog GND).

Then in the Race studio software you click the “Customize sensor” option and create a new sensor (input the data, click compute curve, then save it), once you save it it is available to choose in the channel setup:





The pressure transducer is really a 0-100psi item so I converted it to bar which is why it is set to 6.89 as the max and not 7.