Hi gents
I'm redoing the wiring harness in my Z and hope someone could help. I've come across these wires - which used to connect to the ECU. Here's what I know

Green -> goes to the fuel pump
Red/White -> 12V from the battery

The two that I don't know are the black/white and black/yellow.

From this diagram it looks like the black/yellow goes to the ignition switch among other place and the white goes to the ignition relay and the "IG" part of the fuse box. So would these be 12V switched? I am a bit confused. I've attached photos of the wires themselves as well as the part of the diagram where they are. Any help would be wonderful!

Thank you
Jan

Edited Wednesday at 11:33 PM4 days by Pomorza

11 minutes ago, Pomorza said:

Hi gents
I'm redoing the wiring harness in my Z and hope someone could help. I've come across these wires - which used to connect to the ECU. Here's what I know

Green -> goes to the fuel pump
Red/White -> 12V from the battery

The two that I don't know are the black/white and black/yellow.

From this diagram it looks like the black/yellow goes to the ignition switch among other place and the white goes to the ignition relay and the "IG" part of the fuse box. So would these be 12V switched? I am a bit confused. I've attached photos of the wires themselves as well as the part of the diagram where they are. Any help would be wonderful!

Thank you
Jan

Black/yellow - 12VDC switched from key in START.

Black/white - 12VDC switched from ignition relay. The ignition relay coil is energized by the key in ON.

@SteveJ
Thank you sir!

Hi Jan, You mention a ECU.. but a 280z has a ECCS.. looks like a ECU. but it's a analog computer.

Only the latest 280zx has a ECU, which deals with digital signals. AND most important has a microcomputerchip on board.

A analog computer has a lot of analog input signals and "computes" this to a final signal for the different inputs like the cold engine start injector as an example.

3 hours ago, dutchzcarguy said:

Hi Jan, You mention a ECU.. but a 280z has a ECCS.. looks like a ECU. but it's a analog computer.

Only the latest 280zx has a ECU, which deals with digital signals. AND most important has a microcomputerchip on board.

A analog computer has a lot of analog input signals and "computes" this to a final signal for the different inputs like the cold engine start injector as an example.

There are times to be pedantic. This isn't one.

Actually, the the ECCS was introduced with the 280ZX's. The ECU is used in both but started with the 280Z's. Generally, ECU stands for Electronic Control Unit or EFI contol unit. Edit - not sure what ECCS stands for.

Of course, it's all translated from Japanese, so the words might not make the most sense in English. But that's how ECU and ECCS are used in the FSM.

From the 1982 FSM, below. Might be the the ECCS "computer" should actually be called the ECCSU. There have been some discussions about what should be called a computer. I don't think that either of these actually do any number crunching.

Edited Saturday at 03:34 PM1 day by Zed Head

The 280Z control system could easily have ended up as the EFIS.

6 hours ago, dutchzcarguy said:

Hi Jan, You mention a ECU.. but a 280z has a ECCS.. looks like a ECU. but it's a analog computer.

Only the latest 280zx has a ECU, which deals with digital signals. AND most important has a microcomputerchip on board.

A analog computer has a lot of analog input signals and "computes" this to a final signal for the different inputs like the cold engine start injector as an example.

I'm just going off what here.

They call it an ECU. My FSM calls it a "control unit". Either way, the analog wizardry box that makes the engine go vroom.

I didn't even get my explanation right. I used the chapter label, EFEC, instead of ECCS. I'm not really sure what ECCS stands for.

Just for fun - CECU. Figure that one out.

Edited Saturday at 03:36 PM1 day by Zed Head

10 hours ago, Pomorza said:

the analog wizardry box that makes the engine go vroom.

Don't forget the "black box" or the "voodoo" part.

"Dr. Bosch's Black Box of Analog Voodoo and Wizardry".

That's what makes the engine go vroom.

* "DBBBOVAW"

16 hours ago, Zed Head said:

Actually, the the ECCS was introduced with the 280ZX's. The ECU is used in both but started with the 280Z's. Generally, ECU stands for Electronic Control Unit or EFI contol unit. Edit - not sure what ECCS stands for.

ECCS was first used on the 430-series Nissan Cedric in Japan (June 1979). ECCS stands for Electronic Concentrated (Engine) Control System.

Electronically-controlled (via an ECU) injection was introduced on a 230-Series Nissan Cedric 'EL' model at the 1970 Tokyo Motor Show:

Nissan was actively using a system ECGI (Electronic Controlled Gas Injection) back in 1971. Nissan group affiliate Diesel Kiki licensed the Bosch D-Jetronic system patents and re-engineered it to use with double and triple sidedraught throttle bodies on competition cars: