proxlamus© Posted July 6, 2007 Share Posted July 6, 2007 Help! I am getting 16v at the battery terminal of the ALTERNATOR and 11.7v at the battery... wiring seems to be fine and all fuses are a-ok. Car is a 1978 Datsun 280z.. and I am running a Z31 300zx alternator.. so i believe its an internal regulator.. Any ideas? Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted July 6, 2007 Share Posted July 6, 2007 Sounds like the regulator to me, autozone checks them "in car" I believe. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 6, 2007 Share Posted July 6, 2007 Isn't the "Battery" terminal of an alternator where all the loads are connected? I ask because I'm not familiar with how the 300ZX alt is labeled. If so, then I'd look very closely at the wiring from the alt to your fuse box and also your battery cables. You shouldn't see more than a few tenths of a volt difference between the output of the alt and the battery post. I don't think the issue is with your regulator - I'd be looking at your wiring. I only know the 73 from personal experience, so can't tell you much about your 78, but wiring has never been a strong point for Zs and after all these years I would not be surprised if you had some corrosion or frayed wire near a connector in the circuit that feeds power from the alt to the rest of the car. Also, make sure you don't have a fuse that is intermittent. I had a headlight fuse where the metal end cap had become loose from the glass, and no longer made a good connection to the fuse wire inside. To my eye it looked good. Finally I pulled all the fuses and this one fell apart in my hands. Lesson learned: always pull glass fuses and measure with an ohmeter to be sure they are good. BTW, I think your Z has a fuseable link. (They hadn't been invented yet in '73 ) I'd check those for the same issues. Quote Link to comment Share on other sites More sharing options...
bubbleguinea Posted July 6, 2007 Share Posted July 6, 2007 is your little light for the voltage indicator (red one) working??? Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 7, 2007 Share Posted July 7, 2007 You either have a lot of current running through the wire from the alternator to the battery or you have a lot of resistance in that same line. Those are the only two ways you can get that type of voltage drop across that line. Try disconnecting and cleaning every connection between those two points. How old is your battery? Maybe it is going dead and drawing a lot of current trying to charge. Even with an internal regulator the alternator has a voltage sensing wire coming out of it. The regulator tries to keep the voltage at 12-14v at the point where the voltage sensing wire hooks into the harness. That is usually at the little low voltage light in the voltmeter guage. Try measuring the voltage there and see what it says. The other possibility is the chassis ground. Disconnect and clean up all of those too. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted July 7, 2007 Author Share Posted July 7, 2007 Thanks guys! First off the wiring sucks ass. Last time i did it years ago was terrible.. in addition the alternator was OVERCHARGING and had a bad regulator. Problem solved! Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted July 7, 2007 Share Posted July 7, 2007 Wow, I was right . Haha glad the prob was solved pro. Quote Link to comment Share on other sites More sharing options...
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