Originally between J6 and P7 was the JPI 790802 Signal Conditioner that converted the old resistance readings of the fuel senders to 0-5V for the JPI analyzer.
CiES senders outputting 0-5V, this Signal Conditioner is useless and can be removed. However, you can’t just plug J6 and P7 together and have it work. You have to rearrange the pins on P7 to match up J6.
Looking at J6 from left to right, pin 1 is 5vdc (white), pin 2 is Ground (Blue/white), pin 3 is Signal #1 (Green/White), and pin 4 is Signal #2 (White). The P7 must be reconfigured by moving male pins around to the following configuration left to right, pin 1 Disconnect, pin 2 (Black) Ground at sender, pin 3 Signal #1 (White), pin 4 Signal #2 (White).