Well, I thought I was fixing a lot of wiring issues and removing a few shorts, but now I can't get her started at all. I went back and did the FSM ECU-removed tests and seems I don't have power from the EFI relay anymore.  I'll hopefully track this problem down soon.

However, looking at some other wires in the engine bay, I found these guys (pic below) but couldn't seem to track them down in the FSM.  Either way, I'd really like to fully replace the connectors (or simply remove them).  The wires go from the positive side of battery and into the main harness via a solid blue and solid red wire.  But if you see in the picture, there's two small dirty green wires in the middle.  Are these fusible links? Anyone know what these wires are for? I thought the car only had 4 fusible links in the engine bay (which I have, not pictured), is there actually 6?

 

Update: Scratch that, think i found it. Guess there is 6 total, image attached.  Looks like these may not be easily replaced looking at older posts.  Has everyone done a fusebox swap to address these?

Edited November 1, 20195 yr by S30Grit

The efi fusible links are available for Banzai Motorworks ....

https://www.zzxdatsun.com/catWiring.php

2 hours ago, S30Driver said:

The efi fusible links are available for Banzai Motorworks ....

https://www.zzxdatsun.com/catWiring.php

Ahh, thanks.  Definitely bookmarking that one.  I already bought an inline fuse on amazon that will hopefully do the trick

You can check for power across the links, and measure resistance of the links.  Confirm that they're bad before you buy new parts.

The two green links are the EFI links as you thought, but the wiring job alone might be the problem.

http://www.atlanticz.ca/zclub/techtips/fusiblelinks/index.html

I've obtained a Cadillac Cetera fuse box from a forum member. I've yet to install though but it works well and is inexpensive according to him and I trust him 100%. I will post the info when I crack open my laptop.

The rating for the red links is too high.  Should be about 30 amps.  It's been discussed many times.  Red has replaced brown in popular Z lore for some unknown reason.  Brown is lower diameter than green, as shown in the FSM over many years.  Of course, it only becomes an issue if there's a short circuit.

Edited November 1, 20195 yr by Zed Head

5 hours ago, Zed Head said:

You can check for power across the links, and measure resistance of the links.  Confirm that they're bad before you buy new parts.

The two green links are the EFI links as you thought, but the wiring job alone might be the problem.

yeah, inspecting the connectors to the links, there's tons of corrosion.  And the wire ends/crimps are barely hanging on.  I'd rather just swap the links out.  I'll cut the wire back a little bit to see the condition of the wires. 

I'll be putting two 40 amp in-line fuses in place of them.  I see the fuses vs fusible links has been a hotly debated item, but I haven't read any reports of cars starting on fire, so I'll go with the easier option

Sorry to be late with this and it seems you have a plan already but you can read over it for the future.  It's a brief description of the switch over he came up with.  We may put mine on in Nashville next year.  He said it's that simple.

INSTALLING CATERA MAXIFUSE UNIT INTO A S30.pdf

 

Edited November 3, 20195 yr by siteunseen

23 hours ago, siteunseen said:

Sorry to be late with this and it seems you have a plan already but you can read over it for the future.  It's a brief description of the switch over he came up with.  We may put mine on in Nashville next year.  He said it's that simple.

 

That does look ideal and clean.  I ended up using those large fuses commonly used for amplifier installs.  Easy to connect up, relatively good weather seal...

A final update on this topic:  After chasing down random wiring issues and corrosion, I found the core of the starting issue.  It was ironically simple: the aftermarket ignition relay was not wired correctly. If anyone else finds this thread in the future, the problem/solution is described below:

The previous owner purchased this part (again a Zcardepot part), https://zcardepot.com/products/starter-relay-upgrade-replacement-280z#

It looks like it comes pre-wired from zcardepot but I can't confirm that since I didn't order/install it.  If it was pre-wired then it's not plug and play, at least for the way my car is wired (78 280z) and requires swapping the two blue wires.

Anyways, as many probably know, the "ignition relay" is basically two relays in one: one relay to power ACC (accessories) circuit and one relay for IG (EFI/fuel pump/etc).  In my case, the output of the relays was swapped.  Meaning that my EFI/Fuel Pump/etc were getting power when the ignition switch was outputting +12v for ACC, which is when the key is in ACC or ON position.  But as many know, with most cars, when you turn the key to "START", the ignition switch does NOT output to the ACC circuit ?‍♂️, explaining most of my issues...

Therefore, the solution was to simply to swap the two output wires on ignition relay harness (the two blue wires in the harness). For reference, tests on page EF-27 from the FSM will help identify the problem (you'll find Fuel Pump relays aren't getting power when ignition is in START position).  Essentially the two  ignition relays should be wired as followed:

•    IG relay: WB is the relay "output".  WR is constant +12v.  BW is relay on/off, connected to IG of ignition switch
•    ACC relay: LW is the relay "output".  WR is constant +12v.  LR is relay on/off, connected to ACC or ignition switch

Thanks again for everyone's help.  A lot of terminals a definitely a lot cleaner than before, ultimately the FSM wiring diagrams helped me backtrack through the wiring issues with the starter unplugged..

Edited November 7, 20195 yr by S30Grit

Excellent find! Thanks for posting the solution