charging won't stay

[Z fun car]

I have my car parked right now but the problem that I am having is that my battery goes dead all the time. I charge it up so I can start the car and let it run,but the charge won't stay. The car has a brand new battery. Does anyone have any knowledge on where I can start to look for a power to ground leak? I've recently had a tune up and a brand new exhaust (with a header) done to the car and before this I did'nt have any problems. Any help would be greatly appreciated,thank you guys. P.S. I love this site.

Jim 1972 240Z HLS30-71736

[jimbo99]

Hello,

What year is your Z? On my 74 260z had a similar problem where if it sat for any length of time in cold weather below 50 F or 10 C I'd have no charge. I found in the Nissan FSM the voltage regulator is temperature compensated and is responsible for both voltage and has the charging relay. The FSM has the adjustment for the point gap for both as they change over time.

If you don't have Nissan FSM I recommended you get one for your Z, it has good diagnostic procedure to check voltages at other points in the charging system to help isolate the fault if it isn't the Voltage Regulator. When I took mine apart I found that it was better to replace it after 30+ years, found the correct one on Ebay and the problem hasn't returned. I hope this helps

Jim

1974 260Z - RLS30-020697 (01/74)

[EScanlon]

Disconnect the Negative Pole cable AT the battery. Put a 12v Test Lamp with one lead on the battery and one on the battery cable. (don't use a powered test light, basically you're inserting a plain old 12v bulb)

With the ignition off, key out:

If the bulb glows AT ALL, you have some form of current draw occurring when it shouldn't.

Start with the most common suspect, the accessory relay. On a 70-72 this is mounted on the passenger side kick panel. (Not sure whether Driver or passenger on RHD cars, BUT it IS on the kick panel.) It's usually simplest to first disconnect the relay, then effect the current test above.

If the light is now OFF, then you've found the culprit. If on the other hand it is still glowing, then proceed on down the line.

Basically, disconnect items, and check for current. Once the glow stops, you've found the culprit.

FWIW

E

[Curtis240Z]

The most common problem is bad diodes in the alternator. Try disconnect your alternator overnight and see if the problem persists in the morning after you rehookup the alternator. As with any live electrical device take the proper precautions.