Ls Ultima 70002 system .
NO fuel pump prime on key turn on. Can ground yellow on pump relay pump runs. Couldn't find main yellow fuel pump relay control primary at pin 27. Have schematic of fitech wiring . No pin 27 on ECU connector viewed from harness side. Did find pin 27 yellow on a couple other plugs but they where un-used. So no pump on signal to yellow wire on relay !
"Did find pin 27 yellow on a couple other plugs but they where un-used."
Your post is a little confusing.
There are several yellow wires that terminate in the ECM plug.
Are you saying the pin well for position 27 has no connector pin in it in the harness plug?
You say you have the schematic of Fitech wiring, is it a wiring line drawing or just the list of pins and colors?
Pins and wire's yes many yellow wire's the ones for the fuel pump say that they are the pin 27 on the pin out sheet I down loaded. I was trying to find out where the pump on signal originated from so as to test it the sheet says fitech pin function pin 27. Fitech ultimate LS ECU #7005x pin 27 fuel pump relay control primary YELLOW.
P.S. ECU connector viewed from the harness side didn't show a pin 27 location. A wiring schematic would be nice to chase down the wiring to find the source of the pump turn on signal.