77z battery drains

[Z_Dust]

My 77z has a L28 engine. Every now and then when I go to use the car the battery is dead. The volt meter gauge reads low and the needle moves slightly as if having a pulse. There are no accesories on, the battery and cables are new as wel as the alternator. The car is not a dayly driver but I use it once or twice a week enough to ride around 80 miles every month.

[Guest DRK]

I bought my buddies 78 280z that kept killing the battery. My father is a retired electrical engineer, and suggested checking the alternater. If I remember correctly, it should have high resistance one way, and low resistance the other. Anyway, mine was bad. Another buddy gave me an alternator, and now the battery stays charged, so you might want to check your alternator. My father said the diodes can go bad and cause the low resistance both ways thus shorting the battery and draining it.

[Guest 240hybrid]

You didnt say that your alternator was bad, but I had a similar problem and I fried 3 alternators after having the battery, alternator, and voltage regulator checked and all passed at the time after I replaced the first alternator. Guy doing the check said I had bad wiring.....Dont think so . Drove for about a week and killed another alternator. Did this 3 times all together, and was sick of replacing them....so i replaced the Voltage Regulator(less than $10.00, PRESTO problem solved. I guess the guy doing the check on them was smoke his pipe that day or his equipment was wrong. All I know is that the volt. reg. replacement solved all my problems with battery dying and killing alternators. Might not be the case with yours, but you never know. good luck with it.

[Guest Anonymous]

Want to check an alternator real quick! Start engine let idle and disconncet positive terminal from battery. Engine keeps running smoothly .. you have a good alternator.