If I start the car daily, it runs great. If I let it sit for even a few days (3-4), the battery is completely dead to the point that it cant even be jumped using another car. Twice now I have had to take the battery to get it charged just to get the car started.

Battery is brand new and the car is a 95 z28. I'm pretty good at fixing things but not great at diagnostics. What are the first things I should look for?

I assume there is something drawing power even when the car is turned off, correct?

TIA guys.

 

I would bet something is drawing power after it is off. There is a process of checking this but I can't remember what it is.

 

First if you have what I term a Big Thumping Amplifier, it's probably the problem. If not, the second most common item is anything added that goes directly to the battery and third, anything added that goes to the fuse panel. So you will check in that order.

To check for current draw, remove a battery cable and place the meter correctly wired for current (AMPS) in line between the cable and the battery. You need to know a few things regarding the meter however if you don't already know.

Usually the leads have to moved to a different location on the meter jacks to measure current.
Be sure your meter has a 10AMP setting since you don't know how high the reading will be initially. Then set the meter to that setting. If the reading is much lower than say 1 amp, you can change to a lower setting however be careful if the meter leads must be moved when you change settings. It depends on the meter.
Polarity is only important if you don't have a digital meter.
The single most important thing about a meter that reads current is the meter has at least one fuse. If you measure current higher than the fuse, it will blow and you probably won't realize it. Now when you start looking for leakage current, guess what? The meter reads 0 and you incorrectly think you DON'T have a current leak.

If you take the neg cable off the battery, put the Positive meter lead on the negative battery cable and the negative meter lead on the negative battery terminal. the reading should not exceed 0.02 AMPS.

If the reading exceeds that, and I am pretty sure yours will, remove the items listed above. If that does not reduce the reading, remove and then replace one fuse at a time until the reading moves the most.

 

Thanks alot. When I bought the car it had an aftermarket HU and it looks as though there was probably some sort of subwoofer setup in the back as well. I dont know much about stereo wiring, but there is definitely some extra wiring going on underneath the hood as well. I was assuming that it was somehow stereo related. My next step is to just start checking everything it could be. I'll take a picture under the hood and maybe that will help.

Thanks for the responses.