The car is a '89 Iroc Z with the 305 TPI engine with 183,000 miles. Recently, my 6 year old Delco battery died, so I replaced it. Everything was fine for several days until I let it sit for three days without running it. After three days, I went to start it and the brand new battery was dead to the point where even the dome light wouldn't come on. I tested the battery voltage and it is down to about 1 volt. No ascessories were left on and there is no aftermarket equipment wired up.
What is the most likely problem to cause a current draw when the car is off?
Has anybody had a similar problem and what turned out to be the cure?
What is the best way to test the circuits to find an area drawing current that shouldn't be?
Thanks in advance for any and all responses.

 

Im not very sure. Maybe your alternator is not functioning correctly?

 

You can bring your battery and alternator to your local Napa, Pep Boys, or other auto parts store and they will test it out for you for free to see if either the battery is a dud or the alternator is weak. If both are ok I'd start looking around for wires that might be grounding out

 

It sounds like the alternator is cooked. I had a problem that sounds similar to yours and it turns out the alternator had a short where it would charge but only in intermediate increments and if I left the car alone for a few days the battery would be dead. I had checker test the charging system for a warenty and they said it was charging fine yet I made them give me another and no problems for a year and a half.
SSC

 

It is definitely possible for the alt to have enough parasitic current to drain the battery over the course of a few days.

Easiest way to find things like this is to hook up an ammeter in series with the battery connector, see how much current there is, and if it's too high (like more than 10 mA or so) unhook stuff until it stops. Discdonnect the alt wires, pull fuses, etc. to isolate circuits.

I'd look for something turned on that you wouldn't notice though. Common culprits include the under-hood light and the light for the rear cargo area.

 

I am not sure if your car is the same but I have a 86' T-A
and had the exact problem, as long as I drove the car at least once every one or two days everything was fine, if I let it sit for more that three days the battery would die (far enough to kill the memory in the radio). after many new batterys and a new alternator I found the problem, the rear hatch pulldown was jammed and was constantly pulling power, all I didi was open the rear trim peice and unhook the relay, problem solved !!

 

I want to take this oportunity to thank everyone who responded to this post.
After troubleshootong the system, I found that 1986redbird was absolutely correct. The power hatch mechanism was not capable of pulling the hatch all the way down and continued to draw current that was draining the battery. After opening the hatch with a key, the hatch pulldown motor started to run continuously even after I disconected the relay. So I just removed the fuse for the hatch, and adjusted the latch mechanism to work without the electric pulldown feature.
Again, thanks to all who replied concerning the diagnostic procedures and special thanks to 1986 redbird who saved me a lot of time by directing me to check the hatch motor first. What a great website!