Need a bit of help.

Done the conversion on my S2 with an EFI XR3i loom and OFAC ECU, using the original S2 tank and external pump so pulled what I beleive is the pump wiring ( 2 middle wires )from the 5 pin plug that does both sender and pump on the EFI and soldered on the original ends for the S2 pump. Problem is that the pump will prime but not run when cranking over, tried a different relay but no difference. It will pump when I run a direct live from the battery though .

Anyone had this problem before as its starting to do my head in now