1974 Datsun 260z won't start

[SteveJ]

Just now, lefty7126 said:

And then a buddy off mine who actually knows some what about cars helped me assemble these but that didn't make a difference.

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If that is regular wire, all I can say is DON'T DO IT! You need to use fusible link wire of the proper gauge, otherwise you risk burning up your wiring.

[lefty7126]

Yeah this wasn't recent I joined the forum to get better insight on what the problem might be that way I don't mess it up any worst.

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[Mike]

1 hour ago, SteveJ said:

If that is regular wire, all I can say is DON'T DO IT! You need to use fusible link wire of the proper gauge, otherwise you risk burning up your wiring.

I seem to remember our vendors have this part.

MSA:  http://www.thezstore.com/page/TZS/PROD/12-4328

Zcar Depot:  https://zcardepot.com/electrical/fusible-link-wire-green-oem-260z-280z-74-78.html

[Patcon]

The original cables you posted pictures of are actually very special wires. They act like fuses, if you pull too much current they melt to protect the rest of of the harness. If you replaced them with heavy gauge wire and spade connectors then you transferred that overcurrent into the harness. It is possible you made a bad situation worse...

[SteveJ]

So in case anybody is curious...

I went over to @lefty7126's house today. We tested for continuity between the fusible links holder and the negative cable of the battery. Unfortunately, as I suspected, we found continuity. I moved down to the shunt, unplugged it, and found continuity between the downstream side (away from the fusible link) of the wiring harness and ground. I traced through the wiring diagram for the white/red wire, and we continued to diagnose. First we removed the connection to the alternator. No change. Then we removed the C-6 connector on the engine to dash harness. Still no change. Next we disconnected the C-5 connection. That broke the short. There are two white/red wires on C-5. One goes to the ignition switch, and the other goes to the headlight switch. I disconnect both switches. Each end of both wires had continuity to ground. That was our stopping point for the day.

Lefty's dad is going to pull the dash, and I'm going to return over Labor Day weekend. I believe the dash was out before, and maybe some wires got pinched on the re-installation. It's always good to meet a fellow enthusiast who is willing to get his hands dirty.

@Jeff Berk, I looked at the build date of the car. It's 10/74, making it a "late" 260Z. Some components were rearranged from the early 260Z. The split-loom in the photo actually covers AC lines. There are some other wiring issues to sort out in the car, and those will be easier to deal with once the dash is out.

The car looks to have good bones, too, so it should be a good starting point for Lefty's projects.

@Pat Carr, we ended up going to a great no-name restaurant co-located with a Mexican grocery store. 

[JSM]

Good update and good of you to swing by. Speaking of swinging by, if I drove up to your neck of the woods, can I pick your brain on some wiring schematics I'm working on. Maybe over a weekend sometime. 

Edited August 20, 2017 by JSM

[SteveJ]

11 minutes ago, JSM said:

Good update and good of you to swing by. Speaking of swinging by, if I drove up to your neck of the woods, can I pick your brain on some wiring schematics I'm working on. Maybe over a weekend sometime. 

That's probably over a 7 hour drive each way, but I suppose it could be done.

[JSM]

1 minute ago, SteveJ said:

That's probably over a 7 hour drive each way, but I suppose it could be done.

As many hours I waste looking at the schematics that you could probably explain to me in less than 30 minutes worth it. ?

Maybe I'll bring the wife and make a weekend out of it. 

[SteveJ]

If you come up here, you could take her to the Georgia Racing Hall of Fame (https://www.facebook.com/georgiaracinghof/). No visit to this area is complete without it. Just ask @240260280 or @Captain Obvious. That place really outshines the Georgia Aquarium and World of Coke COMBINED!

[Captain Obvious]

What he said.  

[Captain Obvious]

Oh, and BTW, I think there are three W/R at C-5. One to the ignition switch, one to the headlights, and one to the ammeter.

I hate the 260 wiring diagram...

[SteveJ]

Thank you for mentioning that. The ones that were shorted to ground were the 10 AWG  white/red at either end of C-5. It is curious that two wires that are independent from each other, as far as I can tell, are both shorted. Of course, there could be some previous owner shenanigans at play.