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280z Charging Problems

Old 07-29-2016, 10:39 PM
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280z Charging Problems

I have a 77 280z and it will not charge. I constantly have to jump start it and without being connected to another vehicle, it wont stay running for more than about 20 seconds. The voltage at the battery slowly goes down to about 9 volts and then it dies no matter what RPM it is at. I have replaced the alternator, voltage regulator, and fusible link and it still doesn't want to work. The charge light in the dash goes on when I turn the key to the run position and goes off when I start the car. Does anyone have any other suggestions of what to replace/test?
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Old 07-31-2016, 11:26 AM
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Originally Posted by l28manzz View Post
Does anyone have any other suggestions of what to replace/test?
Read the Factory Service Manual section on the charging system. Rather than shotgun replace parts, do some diagnostic work, figure out what part of the system isn't working and then fix it.

My money is on an open wiring connection (bad ground, connector, etc).
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Old 07-31-2016, 12:44 PM
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I was doing some looking at my connections to the alternator and there are two wires on the positive side. One of them I have traced to the positive terminal of the battery and I have a full connection. The other wire has a female connector on it but is not connected to anything. It looks like the wire goes to a condenser that is supposed to be connected to the alternator's negative terminal but the condenser is missing. Could this be my problem? I traced all of the other wires and they are connected properly.

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Old 07-31-2016, 12:52 PM
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for a start without going to extremes take it to a battery shop. have them load test the battery and check the charging system. at least then you know the battery is good and the charging system is working or not working.
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Old 07-31-2016, 07:08 PM
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Originally Posted by l28manzz View Post
I was doing some looking at my connections to the alternator and there are two wires on the positive side. One of them I have traced to the positive terminal of the battery and I have a full connection. The other wire has a female connector on it but is not connected to anything. It looks like the wire goes to a condenser that is supposed to be connected to the alternator's negative terminal but the condenser is missing. Could this be my problem? I traced all of the other wires and they are connected properly.
Pretty much the only thing a missing condenser is going to do is give you lots of electrical noise on the +12V line. That translates to a whine on your radio that goes up and down in frequency with your RPMs. No, that's not likely to be your problem.

Take RogerZ's advice.
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Old 07-31-2016, 10:50 PM
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I might have to do that. Might it make sense to upgrade the system to a zx alternator? I have read that it is a good upgrade to do. But if I could figure out the problem with my current charging system, that would be better. Thanks for the help.
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