where does the ecu get its ground?

[rbspitfire]

i just got done squeezing a rb20det into a 76 triumph spitfire( no easy task at all), i am trying to hook up ecu to try to start it and am wondering where the ecu gets its ground from? i noticed in the wiring there is a single "block" that all the ecu ground branch off of and was wondering where the ground sources from? right now i dont really have any grounds hooked up because there werent any coming off the harness that i saw?

[FAST-DATSUN]

during the rewiren you need to take the ground out of the old plugs and take them to ground All black with silver dots need to be grounded test EVERYONE of them to insure they have 0 ohms to ground...