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Hi all,

I'll preface this by saying that I am an amateur. I recently decided to try and get my Grandma's '86 Nissan 300ZX (Z31) automatic naturally aspirated V6 (non-turbo) two-seater running. It has sat in my Mom's backyard without being started for at least 10 years. If I boost it, or if the battery is recharged using a trickle charger, I can normally start it for between 30 seconds and a few minutes at which point it dies, and the battery is drained to zero. Sometimes the dash lights come on, sometimes they don't. Based on everything I'd read online it seemed that the alternator was the culprit, so I replaced the battery and the alternator (with a rebuilt unit from NAPA). This made no difference. The car still starts only when the battery is fully charged or boosted and soon shuts off. I haven't even successfully shifted the car into drive. To me, it still seems that the problem is electrical, but I don't know where to look next. Any nudges in the right direction would be really appreciated!

Thanks
 

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Not sure where to go, but what I would do at this point is to gather more info about the electrical system without spending money.

I suggest charging the battery fully, then let it sit overnight and check voltage across the terminals (see note below) before starting the car. Then use your digital multimeter (same that you use around the house, but on 12V DC setting) and check voltage across the battery terminals. You should see 14.4 volts or so, but above 14V regardless while the engine is running. If not, then either the alternator is bad or not connected properly.

It does sound electrical, so keep in mind that wires can break and even a new alternator or battery can be faulty. Let's see if that battery is holding a charge and nothing is draining it overnight, and let's make sure the alternator is charging.
 

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Remove all the fuses, and see if it is still draining the battery. Add 1 fuse and see if it is still draining the battery. If not, pull that fuse and add another one. Is it still draining it then? One by 1 continue trying 1 fuse at a time until you find the one draining the battery. this can take a long time to do.

Another way, if you have a current/ammeter meter, is to remove a fuse and measure across the fuse terminals and see you can find who is drawing the most current. repeat on all the fuses. This could tell you the results much quicker
 

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Hi all,

I'll preface this by saying that I am an amateur. I recently decided to try and get my Grandma's '86 Nissan 300ZX (Z31) automatic naturally aspirated V6 (non-turbo) two-seater running. It has sat in my Mom's backyard without being started for at least 10 years. If I boost it, or if the battery is recharged using a trickle charger, I can normally start it for between 30 seconds and a few minutes at which point it dies, and the battery is drained to zero. Sometimes the dash lights come on, sometimes they don't. Based on everything I'd read online it seemed that the alternator was the culprit, so I replaced the battery and the alternator (with a rebuilt unit from NAPA). This made no difference. The car still starts only when the battery is fully charged or boosted and soon shuts off. I haven't even successfully shifted the car into drive. To me, it still seems that the problem is electrical, but I don't know where to look next. Any nudges in the right direction would be really appreciated!

Thanks
Check the fusible links on the passenger side to the left of the battery. I had one go bad and it gives you effect that your alternator is bad. All my lights on the dash was on so I knew what it was right off. Replaced it and lights went off and everything is good. Hope this helps and by the way just cause it doesn't look bad. Doesn't mean it's not.
 
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