Sorry to be Redundent - Help

[Mark Maras]

Key off.Pull your positive battery cable & with a volt meter see if you have current flowing between the cable & battery pole. Should be little to none. The little bit will be the clock or maybe a few more items on a later Z. A bad diode in the alternator can drain a battery with the key off.You can determine which circuit it is by pulling fuses one by one until you lose the current flow between the battery & cable.

Mark in Portland

[bhermes]

So it is possible that I have been chasing a fuel issue, and very well may have had a rust issue prior to dropping and cleaning the tank, but given that the fuel pressure has seemed to be fine, it appears I may actually have a voltage problem. We finally got a day above 20 degrees and no snow or ice and I went out and started the car. It did start without a jump or charge; however, the voltage at the battery was 11.5 volts. The car was running a little rough and as it ran the voltage dropped to 9.5. I did turn on the turn signal and then back off and the voltage still read 9.5. I played around a little with the fusible links and noticed that the one closest to the front of the car had some green corrosion and was pretty hot to the touch. I moved it around a little and the car shut off. The car was running a total of about 10 minutes. I tried to restart and had to jump with a charger. The battery after it started was 14.6 volts.

Thoughts on the fusible links?

Thanks.

[Mark Maras]

Heat is resistance-poor connection. Sounds to me like you've found the problem. Clean everything, charge the battery. Test the battery with a volt meter, it should read about 12+ volts or so at rest and 13+volts running. The fact that you have good running voltage now, tells me that you opened the circuit when the engine shut off & closed the circuit & made a beter connection than it had before.

Mark in Portland

[bhermes]

Mark thanks. I noticed that some of the connections at the fusible links are loose. Is it a bad idea to crimp down a little on the flag terminal to fit tighter? What should I clean the terminals with? I remember back in 1980, when I owned my first z car, that I had to poor soda in the fusible link to help start the car. OK telling my age now.

I think when I moved the links around a little that I wiped some corrosion off of the terminals and things got better.

I really hope this is the problem.

[Mark Maras]

Very often just removing a replacing the spade terminals will improve the connection. A small piece of emery cloth is what I use. The female only has 3 places to make a connection. The flat surface and the edges of the rolled portion that touch the spade. Squeezing the female end is the correct way to tighten the connection. An afternoon spent cleaning all the connectors and grounds will revive the circuits that have high resistance & low voltage. Deoxit at Radio Shack is also a good choice for cleaning and preserving connectors and contacts. Then a dab of dielectric grease on them will keep them from corroding in the future.

Mark in Portland

[bhermes]

I know that this is not really an EFI at this point but more electrical but hopefully I can close out this thread soon.

Just for some education; why are the fusible links in the system? Why are they needed and not wired directly?

This is probably a really dumb question but thought I would ask.

I cleaned the connections some and squeezed down the flag terminals a little. I will see if the car starts in the morning and voltage is good.

Thanks.

[Mark Maras]

I'm no expert but I'll give it a go. The fusible links are low voltage insulated cables that are there to protect the wire harness in case of severe overload. I've been fortunate over the years & never had trouble with one, but others have. Even after a dead short in the dash board wire harness of my son's 81 RX7 that started a fire, the fusible link was still good. ???? Like I said I'm no expert. Anyone want to correct or add to our limited knowledge?

Mark in Portland

[FastWoman]

Mark, I think that's a pretty solid explanation. Fusible links are very, very slow-blow fuses. Perhaps the fire in the RX-7 was from a faster overload. Modern cars don't have fusible links, as far as I'm aware. Instead they have regular fuses.

[siteunseen]

Fusible link refresh, the very bottom of the page.

http://atlanticz.ca/zclub/techtips/electricalconnections/index.html

[bhermes]

Great guys. After a little cleaning and some light pinching yesterday on the fusible links (not fully cleaned yet with Deoxit) the car had good resting voltage this morning and started without any outside help. Running voltage was 14.7 at battery.

Today's weather should be good enough for a ride so I will know more later. I have the fuel gauge hooked up and will also confirm no fuel delivery issues.

I just love the willingness of people to help on this forum. I hope soon to be able to pass on what you guys have taught me on to others.

One of the reasons i purchased the 280z, other than I just love these cars, was to learn. Never been a mechanic and still know little about cars but learning quickly. It has been a blast so far so thanks again.

[FastWoman]

You're not finished yet, bhermes. You still need to do the Snoopy dance around your newly repaired Z! Anyway, congratulations on finding the problem. Here's hoping your next problem is far, far down the road! (BTW, don't be discouraged if another gremlin pops up sooner, rather than later. The more you work through these early gremlins, the more reliable your car will become. Eventually it will be a rock-solid reliable car.)

[bhermes]

You don't want to see that. One other note, I now have the buzzing noise when the key is in and the door is open. Never had this before. Still no dash lights and fuel gauge doesn't work but thats for another day.

Thanks again.