280z + battery fusible link no continuty

[Ken Kyger]

Was having some issues getting the 78 280z to start today, had the roommate squeeze the fusible link connected to the positive battery terminal together and it started, as soon as he removed pressure the car died.

Had him squeeze real tight and got the plug all wrapped up in electrical tape to hold it. started the car and it died a few moments later, no fuel pressure.

Checked the fuselink and i have a positive 12v current on the pins from the terminal, but i have no continuity from the other side - from ecu i believe?

The ECU is new. Tested it on old and new ECU, same result.

With the fusible link not carrying juice to where it needs to go, the only things working in the car are the dome lights and the radio. No gauges, no fuel pump, nothing important.

Sorry for bad pic quality. Its late here so not much light. At least I found a use for my google glass finally!

[Ken Kyger]

Ive confirmed that the ECU harness is getting absolutely no power to any of the pins.

Any common issues that would prevent the connection from the positive battery terminal to the ecu to complete?

Im really scratching my head here as this one seems to have totally come out of nowhere.

Where does the ECU ground come from? If thats broken, I think maybe that could case this?

[Ken Kyger]

I should also note that none of the other gauges or lights in the car i normally see are working either. The only thing with power is the radio and the dome light.

[Zed Head]

had the roommate squeeze the fusible link connected to the positive battery terminal together and it started, as soon as he removed pressure the car died.

Checked the fuselink and i have a positive 12v current on the pins from the terminal, but i have no continuity from the other side - from ecu i believe?

You have at least one bad fusible link, maybe more. But, the only links I see in your pictures are what might be the EFI harness links (two green ones), which would power the injectors and the ECU. They fail internally, so squeezing and taping them won't work, they have to be replaced.

I don't even see the other four links. Did someone replace them with fuses? I don't see year of car either so I just copied a picture from 1978.

[Ken Kyger]

You have at least one bad fusible link, maybe more. But, the only links I see in your pictures are what might be the EFI harness links (two green ones), which would power the injectors and the ECU. They fail internally, so squeezing and taping them won't work, they have to be replaced.

I don't even see the other four links. Did someone replace them with fuses? I don't see year of car either so I just copied a picture from 1978.

"78 280"

"EFI harness links (two green ones), which would power the injectors and the ECU" thats the one. I have current moving through the wires, so I am 99% sure that the link isnt the issue. If i connect the link to the positive terminal side, i can read the 12v current on the pins on the other side of the link. 12v is making it through the link, but not to the ECU.

I have seen that diagram a few times, but I actualy dont have #2 at all.

[Ken Kyger]

I have noticed that I am no longer getting the current from the ECU on the fuel pump relay when the key is turned to on. My fuel pump relay now has one poitive lead - battery - and three negatives.

There has to be an issue from the EFI harness to the ECU, but that ECU harness is terrifying looking and i have no clue where id even start.

Again, all ECU tests have been preformed on the OG ECU and a new one.

[Ken Kyger]

Is my terminology wrong? Is that 2 green wire plug from the positive terminal to the ECU not a fusible link? If so, I may need to update my posts and redo some research using the correct terms

[Ken Kyger]

You have at least one bad fusible link, maybe more. But, the only links I see in your pictures are what might be the EFI harness links (two green ones), which would power the injectors and the ECU. They fail internally, so squeezing and taping them won't work, they have to be replaced.

I don't even see the other four links. Did someone replace them with fuses? I don't see year of car either so I just copied a picture from 1978.

Im not seeing any other fuses anywhere other than the fuse box by the passenger footwell, so i have no clue what happened to the #2 in the diagram.

[Zed Head]

As I said, the fusible links can fail with no visible outward damage. They're designed that way to avoid fires and melty stuff. Your two green fusible links are either bad or have bad connections. You need to replace them, they can't be fixed.

Follow the white wire from the alternator's B terminal. You'll probably find a Maxi-fuse block, or some inline fuses,or the fusible link block. That wire used to go to the fusible link block when it was bolted to the side of the relay cover. The fusible links look a like a short piece of wire with a female connector on each end.

[Ken Kyger]

As I said, the fusible links can fail with no visible outward damage. They're designed that way to avoid fires and melty stuff. Your two green fusible links are either bad or have bad connections. You need to replace them, they can't be fixed.

Follow the white wire from the alternator's B terminal. You'll probably find a Maxi-fuse block, or some inline fuses,or the fusible link block. That wire used to go to the fusible link block when it was bolted to the side of the relay cover. The fusible links look a like a short piece of wire with a female connector on each end.

I can understand that, but if they were bad, would there still be a solid consistent 12v flowing through them?

It looks like those are inline fuses of some sort?

[Ken Kyger]

Am calling around now to find a replacement for those links, but to me it doesnt make sense that its the links. If current is flowing through them, id think its a problem further down the line.

[Zed Head]

Not sure what you're saying. You said that the voltage went away. "Checked the fuselink and i have a positive 12v current on the pins from the terminal, but i have no continuity from the other". Plus you're getting continuity (resistance) and voltage measurements mixed up. Good that you're measuring but it's easy to get things confused. You could very well have a light connection inside the fusible link that opens up as soon as current flows. And voltage is not flow, it's just the impetus for flow. What do you see with the key On?

On the pictures - those are just wires. Google "280z fusible link" and look at some pictures to see what you're looking for. You might also follow the thick white wire back from the start to see where it goes. It also used to be attached to the fusible links block.

Here's one picture - Post #6. http://www.classiczcars.com/forums/electrical-s30/22763-78-280z-gauge-problems.html