1973 240z Custom Wiring From Scratch

[SteveJ]

Looks good.

[grannyknot]

Making a full harness from scratch is a big undertaking, it looks solid, professional. 

I've used the Tessa tape on a couple projects, it looks great, is good protection for the wires but awful to remove if you screwed up.

[Matthew Abate]

13 minutes ago, SteveJ said:

Looks good.

Let’s hope it works! 🤪

11 minutes ago, grannyknot said:

Making a full harness from scratch is a big undertaking, it looks solid, professional. 

I've used the Tessa tape on a couple projects, it looks great, is good protection for the wires but awful to remove if you screwed up.

Thanks!

Yeah, I discovered that a couple of times. It also can’t be restuck. Once you pull it off it’s shot.

By the way, @SteveJ, I found that it’s possible to lessen the effectiveness of the plastic that catches the tab on the 1/4” connectors, so be careful when you pull off those colored connectors. I had to fix a few spots, particularly where a 12 or 10 gauge wire had been removed.

Edited August 28, 2023 by Matthew Abate

[Matthew Abate]

Been a minute, so here’s a progress report:

I didn’t take any in progress shots of the body harness as I wrapped it, but here’s the final product, coiled up.

One thing I found was that if I wrap the whole thing tightly with string it’s a lot easier to get everything taped off and wrapped in the Tesa tape. I just did the string in the opposite direction so I could unwrap it a bit at a time as I went around it with the tape.

I used a harbor freight fish tape to get it in, so it wasn’t a very tough job. $15.

I messed up my measurements for the light and defroster wires somehow, but thankfully they’re about 18” too long, rather than too short, so I can cut them down and redo the terminals. Just need to get another set of 90° 6.3mm terminals for the defroster.

Oh! And a 52mm blanking grommet for that hole under the battery.

Edited October 22, 2023 by Matthew Abate

[Matthew Abate]

Can anyone point me to a place where I can buy the female partner to this male plug on the fuel pump?

[SteveJ]

Eastern Beaver

Here: https://www.hi-1000ec.com/product/1139

I have used both places. 

[Xylemer]

Just want to say a quick thank you everyone that contributed to this post. 

@Matthew Abate This is going to make my wiring project go so much smoother. I have been searching high and low for this information. There is just so much missing and incorrect information out there. Having everything in one place and documented with such detail is a lifesaver. 

The Z community Rocks!

[Matthew Abate]

Haha! Thanks.

Note that there are some errors in those older spread sheets. Make sure you triple check everything as you go! I’ll post the latest info when I can.

Dashboard wiring should start next month.

[Xylemer]

@Matthew Abate I too am going through my entire harness, but not to the same extent as you. I'm not replacing all the wire. Not that it's a bad idea, just not in my budget. I will be making repairs and modifications to support fuel Injection since I am going back with a RB instead of the L series. I am working with a fairly low mileage Z. I do plan to clean all terminals with Deoxit when it goes back together to ensure good connections.

You mentioned adding an additional fuse in one of the previous post. I thought I might share my current project. I have a fuse box I pulled from a S14. I plan to install in the same location as the original fuse box. I want the dash harness to remain as close to stock, so I'll wire it up with the original connectors. Ideally it's basically plug in play with addition of relays and extra fuse circuits. 

There may be better aftermarket fuse box option, such as the Bussmann. This didn't cost me anything and has lead to me having a much better understanding of fuse box and wiring in the car. Your work here has also helped pave the way. 

Hopefully everything works out. This S14 fuse box should be an upgrade from the outdated stock fuse box and offer plenty of expansion for in fuel Injection setup. 

[Matthew Abate]

Pretty cool! I’m surprised how well that fits so far.

[Matthew Abate]

@SteveJ,

I'm working on my dash harness and want to check with you to make sure I am wiring up this headlight relay correctly. Is it okay to run those to wires from the headlights straight to ground?

Also, I could run a wire directly from the alternator to the B terminal instead of coming off the fuse box stud, right?

[SteveJ]

It took me a few minutes to reconcile things since you are only showing one part of the circuit. Yes, that looks correct to me. 

Since you have pulled the ammeter out, yes, you could pull the power for the B terminal from the B terminal on the alternator. I suggest putting a 10A inline fuse into the circuit near the alternator to protect the wiring if that's the direction you go.