1978 280Z - Won't restart when hot, all interior gauges, fan motor, backlighting not working

[NocturnalEmber]

21 minutes ago, Yarb said:

This is not to be insensitive by any means… Are you sure the G3 filter is oriented correctly with the arrow pointing to the pump. It’s easy to get confused when gas is running everywhere.

No offense taken! Sometimes it pays to look over things again to make sure. I actually double checked that before I put it in myself, and re confirmed just now; The flow arrows are pointing towards the pump, so all is good there!

 

 

18 minutes ago, Zed Head said:

You didn't say if you cleaned and tightened the loose fusible link terminal.  If it responds to a wiggle it's loose.  (All of this wiggling and squeezing is making me feel funny.  Says Garth).  You can just just squeeze them tighter with a pair of pliers.  Don't forget to check the two green EFI links from the battery positive post.  And, of course, check your grounds.

I did clean the fusible links with some DeoxIT, though I only sprayed the respective male/female connections on the car and in the links themselves (this was done probably about a week ago.) No corrosion visible, but I'll pull back the sheath on the links and take some pictures today as part of what SteveJ asked. I will look into tightening them.  Grounds seem fine (at least all the ones I am aware of: Battery negative, starter, engine, alternator, intake manifold grounds, one near the AFM.)

@Zed Head I actually wasn't aware there was a fusible link running off the battery positive post.  Do you have an image by chance? I've seen it in the FSM just now, but I'm not sure if that would assist me in locating it 100% (also how would i test that, any specific amount of ohms I'm looking for? or would it just be a completely open circuit?)  TIA!

[Zed Head]

The link holder is connected to the positive post.

[NocturnalEmber]

52 minutes ago, Zed Head said:

The link holder is connected to the positive post.

 

 

@Zed HeadThat was the page I looked at I believe. I'll open the hood and take a look but the diagram to me reads somewhat confusing. To me it looks like it points under the mounting plate the other fusible links are on to a black spot lol.

Would you happen to know what keywords I could use to get a good image of it so I know what im looking for?

My keywords haven't turned up anything except four easily visible fusible links.

 

Also I just test each end of the car for resistance/continuity I'm guessing? Any specific numbers I'd be looking for? Or just not open/infinite?

Edited August 27, 2023 by NocturnalEmber

[Zed Head]

Somewhere between the terminal on the battery and the other end of the battery cable at the starter, there should be a another wire with a white plastic connector that has two green wires heading off to the EFI system.  Open the cowl cover and take a look.  Take a picture and post it.

[NocturnalEmber]

45 minutes ago, Zed Head said:

Somewhere between the terminal on the battery and the other end of the battery cable at the starter, there should be a another wire with a white plastic connector that has two green wires heading off to the EFI system.  Open the cowl cover and take a look.  Take a picture and post it.

@Zed Head I think I found what you were talking about. I never knew they were a fusible link, though.

 

I've attached a few pictures of every angle I could get, but that's the only obvious thing I could see under the cowl coming off the positive terminal and what looked like it also ran off to another harness.

[Yarb]

That’s them. One looks burnt somewhat

[Yarb]

Disconnect and ohm it out

[NocturnalEmber]

I'm assuming I'd just disconnect the white plug at both ends, so I'm left with just the links themselves and the connectors at each end, and i'd just stick one lead into one side and the other lead into the opposite side of the same fusible link, check the resistance, and repeat for the other one?

Is there a specific range of ohms I am looking for?

[SteveJ]

4 minutes ago, Yarb said:

That’s them. One looks burnt somewhat

And to add on to @Yarb's post, fusible links are designed to burn up internally and leave the insulation intact.

Just now, NocturnalEmber said:

I'm assuming I'd just disconnect the white plug at both ends, so I'm left with just the links themselves and the connectors at each end, and i'd just stick one lead into one side and the other lead into the opposite side of the same fusible link, check the resistance, and repeat for the other one?

Is there a specific range of ohms I am looking for?

Touch the leads together on your meter. The reading may not be quite zero, and that's the reading you should get when you measure across the links.

[NocturnalEmber]

5 minutes ago, SteveJ said:

And to add on to @Yarb's post, fusible links are designed to burn up internally and leave the insulation intact.

Touch the leads together on your meter. The reading may not be quite zero, and that's the reading you should get when you measure across the links.

@SteveJ, @Yarb, @Zed Head I again appreciate the effort! I will go and ohm the fusible links out.

 

I do have one question, though. Assuming one of these links fail the ohm test, where would I source replacements?

 

I've looked online and all I can find are the four common fusible links on the strut tower.

[SteveJ]

The green fusible links are green fusible links. https://zcardepot.com/collections/electrical/products/fusible-link-wire-green-280z-1974-78?_pos=9&_sid=4a0072d4b&_ss=r

Now you might need different terminals, but those are available through a myriad of sources, including Vintage Connections.

That reminds me. I need to generate more content for YouTube. Wire crimping would be a good topic.

[Zed Head]

You could also check power at the EFI relay.  That's the green links circuit.

Edited August 27, 2023 by Zed Head