What Engine Harness is this?

[DAT280zSUN]

So I just pulled an engine harness from a 280z in a junkyard to put into my 77. The junkyard website said the car was a 77 and that is what was painted on the side of the body by them. We just pulled my old harness and laid them side by side to examine them and see what connections may need to be swapped over etc.

Here's where I am stumped. my car has this round plug for the voltage regulator...

But the one we pulled from the car, supposedly the same year. Has no such connector nor and cut wires that look like they would have gone to this connector.

Anyone know if this harness changed at some point or what year it would have been different from a 77?

[Captain Obvious]

Edited... Just re-read your post and what I think is a typo threw me for a loop. You meant to say that the harness has no such connector nor (any?) cut wires, right?

If that's the case, then I'm with the rest of the crowd. You got one from a 78, not a 77.

Edited June 23, 2014 by Captain Obvious

[Zed Head]

The wrecking yards in my area get the year wrong all the time. If they went by the build date, it might be a 78. 78 had the internal regulator.

[siteunseen]

My late '77 has that plug. It also has the sloped up rear deck, does yours? I think in July or August they called them "late '77". Mine build date is 08/'77.

[DAT280zSUN]

there's no cut wires and the harness wrap appears untouched. im kinda thinking the car in the yard was a 78. other than the regulator there seems to be no differences in the harness. theoretically i could just get a newer alternator amd i should be good to go right?

[Captain Obvious]

I'm not so sure it's that easy. There were other changes made between 77 and 78 with respect to the fuel pump control and FI control relays. The 77 uses the dual relay above your left knee, while the 78 uses separate relays over on the bracket by the battery. The one that used to hold the voltage regulator.

I'm not sure which harness those relays connect to... The main engine bay harness, or the engine bay harness.

[DAT280zSUN]

I may be switching to carbs. so im not concerned with the efi controls. do i have to do anything with these wires if I dont use them? I grabbed all the relays from around the bracket by the battery tray when I pulled the harness from the junk car. Pretty sure I have all of them. so if i keep the efi should i be good to go?

[Zed Head]

The fine people here can get you close but you won't really know unless you dig in yourself.

The EFI harness is almost completely separate from the body harness. It has its own power wires and ground wires. There are connections to the fuel pump relay, which you may or may not need for carbs, and a few other indirect connections which aren't needed to power the car and can be disconnected, like the wires to Pin 1 from the coil (although the wire does need to stay connected to the tach).

But, you said you pulled an "engine harness". It's not really clear what that is, the EFI harness is a separate harness and doesn't have a voltage regulator connection. Your best option is to study the wiring diagram and see what you can figure out. A few member of this forum have worked up some nice color diagrams. Here's 1978, and 1976 which is close to 77. 77 might be out there somewhere too.

http://www.classiczcars.com/forums/misc-s30/44992-somewhat-color-wiring-diagram-1978-280zs-enjoy.html

http://www.classiczcars.com/forums/open-s30-z-discussions/36494-free-full-color-wiring-diagram-1976-280z.html

[DAT280zSUN]

It was the engine bay harness, runs the lights, starter etc. my Fi harness is a hack job after the previous owner tried to go megasquirt.

[280zzzzz]

I was under the beer can holder (relay bracket) myself today. My August 76 model (has sloped interior rear package shelf) has the same - 2x Fusible link Holders / Voltage Regulator /Condenser / and the (capped) round 3 pin connector which I believe is used with AC or Seat Belt Relay used on Automatic cars. Like you, I have struggled with the wiring (and other) year to year to year changes on these cars. Something that has been helpful to us, (besides printing all of the 75 76 77 78 Factory Service Manuals - which detail (some of) the changes, and integration of the electrical components) are the Z Tech tips/electrical @ AtlanticZ.ca - We are swapping to triple Webers - and will be removing the EFI harness and components, and switching to MSD 6AL ignition. Not being and expert (HA) it has been an ongoing process - you will find good people here. I understand that this is not a "How-to" deal, and lots of study and struggle is part of the equation. Good luck with your project.