Ignition-switched power not working

[aochider]

This is more of a general car question, but it happened on my 1978 280Z with a Holley carb.

I started the car just fine and had it idling so I could set the timing. It took me 5-10 minutes (or so, fast idle was still active on the electric choke) to get my timing gun and when I get back to the car, it dies right away. It was running just fine and then stopped as if someone turned the ignition to Off. After that, the car wouldn't start and any ignition-switched items do not work either (such as the wipers, turn signals). The constant power stuff like headlights work fine. The battery is at 12.62V and I had it load tested at a specialty battery shop just 2 months ago, which was when a similar thing had happened to me (except I was on the highway that time!). The time two months ago, however, seemed to fix itself.

So, I don't suspect the battery, but I still tried jumping it to no avail. I also put in a new ignition switch, and same result. I checked all of the fuses on the passenger side and they all looked good. I'm stuck. The only thing I can think of with this time and the last time two months ago is that it was exceptionally hot. I have run the car fine since then, but they were at times that were at least 10F cooler.

It seems to me that wiring is the only thing left, but I'm new to working on cars so I'm afraid that there might be some other component that can cause such behavior.

Thanks!

[240260280z]

Could be fusible links too....for loss of power to accessories.

The ignition modules are prone to fail and start to randomly kill the spark until they cool.

The ignition switch can also cause problems.

[aochider]

Could be fusible links too....for loss of power to accessories.

The ignition modules are prone to fail and start to randomly kill the spark until they cool.

The ignition switch can also cause problems.

okay, thanks.

ill check the fusible links (because ive already replaced the ignition switch). would the ignition module have anything to do with things like the wipers and turn signals?

[Zed Head]

A list of what works and when might offer a clue or two. Key Off, Acc., On, does the starter turn the engine?

If it's not working now, check both sides of each fusible ink for power before removing or messing with them. Just carefully poke your voltmeter probe in to the mounting blade without disturbing anything. Then you'll know if that's the problem. If you just rip them off, clean them up and put them back on, and the problem goes away you'll never know if that was really the cause. Actually, I think that there is just one Ignition fusible link, so focus on that one. Check the sides of the mounting block for a label.

The ignition relay is another possible cause. It's in a damp location and they do get rusty. Mine was bypassed when I got my car.

[aochider]

A list of what works and when might offer a clue or two. Key Off, Acc., On, does the starter turn the engine?

If it's not working now, check both sides of each fusible ink for power before removing or messing with them. Just carefully poke your voltmeter probe in to the mounting blade without disturbing anything. Then you'll know if that's the problem. If you just rip them off, clean them up and put them back on, and the problem goes away you'll never know if that was really the cause. Actually, I think that there is just one Ignition fusible link, so focus on that one. Check the sides of the mounting block for a label.

The ignition relay is another possible cause. It's in a damp location and they do get rusty. Mine was bypassed when I got my car.

thanks for the info!

im not sure about Acc., but On and Start do nothing. i tested things i would expect to work when in the On position, specifically my wipers and turn lights. the dash brake light also doesnt work. and the engine does not crank at all when in the Start position. there are no relay sounds either in any key position.

EDIT: im going to go out and see if voltage will run through the 4 wires that connect the ignition switch. i did that yesterday and it looked like small voltages were running between them, but maybe i made a mistake and one of them is dead.

Edited August 3, 2014 by aochider

[Zed Head]

Go directly to the ignition fusible link. It's easy to get to and you'll know a lot more. The connections are exposed and they can oxidize and lose contact.

The ignition relay is also pretty easy to get to but is a little more complex to check. There's a color wiring diagram on this forum somewhere that will make things easier.

Found it. It's pretty big though and it looks like you're on a phone, from the lack of capital letters and poor punctuation. Too bad. Good luck

http://www.classiczcars.com/forums/misc-s30/44992-somewhat-color-wiring-diagram-1978-280zs-enjoy.html

Edited August 3, 2014 by Zed Head

[aochider]

Go directly to the ignition fusible link. It's easy to get to and you'll know a lot more. The connections are exposed and they can oxidize and lose contact.

The ignition relay is also pretty easy to get to but is a little more complex to check. There's a color wiring diagram on this forum somewhere that will make things easier.

i just checked them, and the black one (my labels are worn off) was barely, mostly-not functional. i put in another piece of wire just temporarily to check, and sure enough it works!

im guessing i can just get the same gauge of wire to replace it?

thanks a lot for your help everyone.

[SteveJ]

NO!!!!!!!!!!!!! That is a FUSIBLE link. The wire is different. If you do not use fusible link wire, you could burn up your wiring harness.

[aochider]

NO!!!!!!!!!!!!! That is a FUSIBLE link. The wire is different. If you do not use fusible link wire, you could burn up your wiring harness.

whoa, okay, that is good to know! thanks for telling me. ill go to the local auto store and i imagine they should have some fusible link wire.

EDIT: i should also mention im working on cleaning this one up to see if that will be enough, but im do like to go out sooner-rather-than-later to buy little, cheap things that i may need.

Edited August 3, 2014 by aochider

[SteveJ]

They very well could. Read up before you go: Weather Pack Environmentally Sealed Connectors | Weatherpack Terminals and Seals | White Products Cleveland Ohio.

[SteveJ]

Also, if you want exact replacements (and can wait for them), they are available at Courtesy Nissan: Body - Electrical :: 240Z, 260Z & 280Z Parts (S30) 1970-1978 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com.

You can also find them at Motorsport Auto Z Car Parts.com -- Motorsport Auto -- Home

[aochider]

Also, if you want exact replacements (and can wait for them), they are available at Courtesy Nissan: Body - Electrical :: 240Z, 260Z & 280Z Parts (S30) 1970-1978 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com.

You can also find them at Motorsport Auto Z Car Parts.com -- Motorsport Auto -- Home

thanks for finding those links. im going to keep cleaning them and reading this diagram to better understand how it works. it pretty much looks like all four of mine are in pretty rough condition so i might as well clean them all for now.