hi just wondering my 280zxt drains the battery if i dont drive it with in 3 or 4 days what could it be thanks.. also my tach(rpm) doesnt work i tried 3 different clusters and nothing any ideas thanks

 

Try Checking The Amperage Draw From Ur Car Disconnect The Positive Wire And Connect A Ammeter In Series With It And See How Much Power Being Used Wen key Is Off Usually Somewhere Between 200mA – 500mA. If Its More Than That Then U Might Have An Accessory Not Turning Off Properly Or Something if The Amperage Is Fine U Might Just Have A Bad Battery

 

Yes check the current draw with the car off. The only thing using the battery should be the clock on a stock setup. Do you have a car alarm or aftermarket stereo?

An old/bad battery will drain itself from sitting. You can have the battery/alternator checked as well if there isn't a draw when the car is off.

 

go to a real battery shop (ie not walmart). they will usually load test the battery and check your charging system for free. that eliminates two things if they show good. next you need a vom (and a cheap ammeter to be safe) to put in series with the battery and a disconnected battery cable ( I use positive some will tell you to use negative). either will work. if it takes days then probably safe to use the vom. if you have a draw start pulling fuses until it stops. then you have to find out why which is the really tricky part.