bmpacman Posted May 4, 2012 Report Share Posted May 4, 2012 Hi everyone, I recently bought a '76 280z. My dad and I took it out Sunday so I could learn how to drive it (yes, I bought a manual even though I don't know how to drive one). I didn't want an automatic and all of the cars we own/have owned for the last 12 years or so have been automatic so I haven't had the chance to learn. Anyway, we were about to pull into a parking lot when the car died. We pushed it and got it going again, only to have it run super rough for about 15 seconds and then die once again. The battery in it was good, but we replaced it anyway. We also replaced the alternator a few days back. I took it out with my mom Tuesday night and drove it for about an hour at night with no issues; I even took it on the freeway. After my mom left the headlights on overnight, the battery was completely dead Wednesday. I jumped it, but it idled for about as long as I had charged it (a bit less, if anything), then the rpms started to drop and eventually it gave up and died. I removed the alternator today and had it checked and it came back as good to go. From what I can tell, the battery isn't receiving a charge (or at least not much of one) from the alternator. I took a couple pictures of the wires connected to the replacement alternator, but my desktop doesn't have an SD card reader so I'll have to upload them on my laptop. Any thoughts on what could cause this and what could solve it? Thanks. - Brandon Quote Link to comment
bosifus Posted May 4, 2012 Report Share Posted May 4, 2012 Is the charging warning light coming on when you start the car? I had the same type of thing happen recently and it ended up that the dash warning indicator bulb was blown and needed to be replaced. Once replaced it completed the "sense" circuit and the alt started working. Another thing to check is bad grounds. If you have a voltmeter get the battery charged, start the car and with the neg probe to the neg battery terminal put the positive probe on the case of the alternator. You should have lower than .3 volts reading. If you don't find and clean the ground points on the chassis and engine block of the car. Look over the wiring for the ground as well, with cars this old it isn't uncommon for the wire to be brittle and break. Quote Link to comment
banzai510(hainz) Posted May 4, 2012 Report Share Posted May 4, 2012 Z cars have volt meters in them right? what does it say when running? Buy a volt meter and read the voltage across the battery when running. and then with the lights ON take a volt reading then also. Battery cables good. (more or less what Bosifus sad said above) Theres a Z car place near I 5 up in Everett go there as a last resort. Quote Link to comment
datsunaholic Posted May 4, 2012 Report Share Posted May 4, 2012 '76 Z car uses an external regulator I think. Don't know for certain. 1)The battery and alternator could both be good but with a bad regulator it wont charge 2), or the wiring is bad between the alternator and the wiring harness, fusible links, etc. If you have a 12V reading at the alternator Batt terminal with the car off, then at least that wire is OK, I don't remember if the Z-car has a charge light. If it has one and it's blown the alt won't work. Quote Link to comment
ggzilla Posted May 5, 2012 Report Share Posted May 5, 2012 +1 Bad CHG light in dash Or bad Fuse in Fuse box Or bad voltage regulator Check the voltage at the battery, engine running at 1500 RPM. It must be 13.5-15.5 volts to charge correctly. Quote Link to comment
bmpacman Posted May 5, 2012 Author Report Share Posted May 5, 2012 Alright I did some tests just now. - Voltage on the battery connectors while the car was running at 1500 rpm was 12.14 - The charge light does come on when the key is turned to "ON" - The fuses all seem good - I didn't get any reading on the alternator case - I didn't get any reading on the BAT terminal with the negative probe placed on the negative battery terminal Quote Link to comment
ggzilla Posted May 5, 2012 Report Share Posted May 5, 2012 I didn't get any reading on the BAT terminal with the negative probe placed on the negative battery terminal That indicates a wiring problem. The alternator BAT terminal is supposed to be a direct wire to the Battery + terminal EXCEPT for the Fusible Link. Most likely that is the problem, a corroded connection to the Fusible Link. This is right at the battery cable, it is the two small wires that run off the battery. Check those. Quote Link to comment
bmpacman Posted May 7, 2012 Author Report Share Posted May 7, 2012 Ok, so how would I go about checking the connection to the fusible link? And how would I replace it? Also, to save myself from making another thread, I've also got the issue of the turn signals and hazard lights not working. The front driver side is burnt out, but I don't think that would cause the whole system to stop working, would it? There is also no indication on the dashboard when trying to use the signals or hazards. Quote Link to comment
banzai510(hainz) Posted May 7, 2012 Report Share Posted May 7, 2012 fix the bulb first up front. Fusable link? If you have connection from the starter post where the battery cable goes to. and from there the wire is good to the fuse box I say the fusable link is good. Its just a wire design to burn up in case of too much current. So if you have 12volt feedinf the fuse box I say its good. Quote Link to comment
datsunaholic Posted May 7, 2012 Report Share Posted May 7, 2012 280Z's have 4 fusable links. They're under those 2 square plastic domes on the passenger side. You either buy the links from the dealer or make your own. You can get fusible link wire at NAPA. Don't make it out of regular wire. Prior owner did that on one car I owned and I didn't notice. At least, not until the entire wiring harness burned up and I had a fire under the hood. It's possible the turn signals are on the same fusible link as the alternator... Quote Link to comment
bmpacman Posted May 7, 2012 Author Report Share Posted May 7, 2012 fix the bulb first up front. Fusable link? If you have connection from the starter post where the battery cable goes to. and from there the wire is good to the fuse box I say the fusable link is good. Its just a wire design to burn up in case of too much current. So if you have 12volt feedinf the fuse box I say its good. 280Z's have 4 fusable links. They're under those 2 square plastic domes on the passenger side. You either buy the links from the dealer or make your own. You can get fusible link wire at NAPA. Don't make it out of regular wire. Prior owner did that on one car I owned and I didn't notice. At least, not until the entire wiring harness burned up and I had a fire under the hood. It's possible the turn signals are on the same fusible link as the alternator... I'm just going off what ggzilla was saying- that it's likely a bad connection to the fusible link. I was told that a bad fusible link would have melted if it went. Quote Link to comment
datsunaholic Posted May 8, 2012 Report Share Posted May 8, 2012 They melt internally. They don't necessarily show outward signs. Check for +12V on each side. Quote Link to comment
bmpacman Posted May 8, 2012 Author Report Share Posted May 8, 2012 Alright, I got myself a new digital multimeter (as my other one crapped out on me) today and tested the battery voltage for a reading of 12.38 volts. Then I checked the 4 fusible links. Each has 12.38 volts going in, and 3 out of the 4 have 12.38 volts going out. The one that didn't is the black (alternator & ignition relay). I'm under the impression that this is the problem, and I just ordered a replacement. Quote Link to comment
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