So I got to researching and reading around here and other forums on my particular issue with getting the speedometer to work. I tried using the sticky from the electronics forum but it did not work in my case.
My setup: 93 FD Touring, LS1, GTO T56, PSI Conversion Har-1013 engine wiring harness
I've been having issues wiring anything through the x-14 connector, I have the dash side of the connector but not the engine harness side, and every time I tried to tap into the x-14 harness for the speedometer, the coolant, and the rpm it never worked for me. So I decided to go straight to the gauge cluster with everything.
So for this part of the gauge cluster I did the following to get the speedometer to work.
http://www.dakotadigital.com/pdf/sgi-5c.pdfPOWER: any switched 12V source
GROUND: any ground source
INPUT: LS1 Pin 21 Red Connector. Purple/white wire (the PSI conversion harness the input is actually a black wire)
OUT1: FD RX7 Gauge cluster wiring yellow/red (3C on the gauge cluster diagram) I tee'd into this wire
1,2,3,4 dip switch: off, on, off on
The coarse/fine part: I put the rears on jack stands and I remember following my wife at 2000rpm in 6th and it was at 75mph, so I adjusted that setting pressing the down button until the speedometer was at 75mph at 2000rpm in 6th.
I tried OUTPUT3 like it was in the sticky, but it did not work for me. OUTPUT1 was the one I use to wire directly to the back of the gauge cluster.
Hopefully this helps other people out. Cheers