If anyone knows what this relay/device is here in my picture next to the voltage reg it would be great.

I can only guess that the 7 pin round plug in the second photo connects to it as its the only one in the area even though half the wires are missing and the colours dont match.

The real fun part for me is the starter wire from the ignition switch is the black/yellow that runs to the plug and never comes out again so I'm stumped as to how the old motor used to start. Probably a very obvious answer out there...

NOTE: RHD car so wire colours may differ

Which of your cars are you working on?

Sorry, this is a '77 Australian 260Z which means non-EFI but all mixed up with some of the US 280Z "improvements".

An aftermarket part may not have the correct wire colors on it. What are the colors from the engine harness side? Put the colors in order and tell us if it's clockwise or counter clockwise as you're looking at the plug side.

Engine harness side is the plug pictured.

I will modify this post when I get home for the pin numbers, however the colours are as follows and where I have traced them to:

Black - Ground

Black - Ground

Green/Yellow - Dashboard

Black/Yellow - Ignition Switch (starter)

I only assume this engine loom plug and relay plug mate together as they are the only mating plugs in the area I can see.

I had everything documented in photos but had a hard drive failure.

Thanks

Well from this diagram, I would say it's the seat belt relay.

I thought so too, however the starter wire goes in but does not come out again like in the diagram.

Worst case I will just throw it out and wire the starter wire directly to the starter motor, however I would have like to understand it first.

Thanks for your help so far.

Which positions on the connector are empty? Choose one of the wires as #1, and describe the connector from there. It could give more clues.

I took some more photos as suggested.

The plug on the engine harness side is looks like it is pinned the same as the '77 280Z diagram for the Seat Belt/Starter Relay, however the wires do not go to the corresponding locations.

For instance the black wires are both ground as mentioned earlier which is incorrect to the '77 diagram.

I did notice that the Green/Yellow has a break out wire possibly near the starter with female bullet terminal on it, perhaps this was the starter input?

I also included a photo of the relay plug for reference.

I found an in situation photo here if that helps identification:

http://www.viczcar.com/gallery/displayimage.php?pid=846&fullsize=1