Gavin Posted June 4, 2007 Share Posted June 4, 2007 Having a problem with my dad's car - Stock 78 280z. When the car is at idle, the voltage will have a normal reading ('normal' being the BS ~16v that the gauge typically reads on our cars), but the light on the gauge will be slightly lit. But when I start driving, the gauge lights up completely under acceleration and the needle moves all the way to the right, past 16v. I have replaced the alternator and battery, and also checked the main ground and power to/from the battery. I'm guessing this is a bad ground somewhere, where should I be looking? Thanks Quote Link to comment Share on other sites More sharing options...
Gavin Posted June 12, 2007 Author Share Posted June 12, 2007 Nobody? Quote Link to comment Share on other sites More sharing options...
DCZ Posted June 12, 2007 Share Posted June 12, 2007 Measure the voltage at the battery terminals with a real volt meter. If you have more than ~14.5 volts when you rev the engine to 2000 rpm then your voltage regulator is likely dead or not connected properly. I'm not sure if the 78 has internal or external voltage regulation. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted June 12, 2007 Share Posted June 12, 2007 Make sure you have a good solid connection between the battery and the alternator. Generally, go over all the grounds and wires looking for corrosion inside the wires. Disconnect and clean all terminals in the vicinity of the battery, regulator, starter, and alternator. Also, take out the fusible links under the white covers on the right inner fender. Clean all those connectors as well. I am assuming the regulator is working but might not be getting accurate voltage readings due to faulty connections or wires. Quote Link to comment Share on other sites More sharing options...
HizAndHerz Posted June 12, 2007 Share Posted June 12, 2007 Edit: Nevermind. Everything I was going to say was covered above. Quote Link to comment Share on other sites More sharing options...
Mr.INSANE Posted June 14, 2007 Share Posted June 14, 2007 Voltage Regulator Underneath the fusibles Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted December 3, 2007 Share Posted December 3, 2007 Did you figure this out? I am having a simular issue, in that my Autometer voltage guage is reading 18V+ anytime the key is on. Batt reads 14 something, 1 wire GM alternator, all wiring is new, ground is fine... Quote Link to comment Share on other sites More sharing options...
Yardbird Posted December 23, 2007 Share Posted December 23, 2007 Voltage Regulator Underneath the fusibles 78 voltage regulator is internal. Quote Link to comment Share on other sites More sharing options...
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