Have been reading and reading. Plus looking at the FSM. I think it might be the thermo switch I see in the FSM that is connected to the IC module on the side of the distributor?

I have installed a fuel only mega squirt ecu and I'm trying to get rid of everything I don't need anymore. Putting in bigger injectors and a new fuel rail etc.

As a second question what is the thermo switch shown in the FSM on the wiring for the distributor used for?

Oh it's a 83 n/a 280zx 5spd

I put a black arrow on the pic, you might have to click view raw image to see it better.

 

Idle air?

 

It's not vacuum related. It's some sort of coolant temp probe. It's in the coolant line on top of the intake with 2 round wires going to it.

I checked t with my meter and cold it a short. I have not checked it hot yet. My guess is it will open when the engine gets to temp.

 

Pretty sure its the thermo switch, it has something to do with the ignition system, probably tells the distributor when to go to hot operating mode, instead of cold.

 

Mrprofile nailed it.