To begin with I have a 2005 Coupe with about 38,000 miles. A procharger and catback are basically my only mods. I have put about 10,000 miles on the car since I have had it.

Anyways, I went out to my car after after it sat for about 12 hours and the battery was completely dead. So I charged it up, went to Advance Auto Parts and had them test it. It turned out my battery was bad. Next, I ordered an Optima Red Top and got it yesterday. I put the battery in and the car started up just fine. I let it sit for about 3 hours before I went to work and it started just fine again.

Now for the bad part. I work 12 hour shifts and after I got off work I went out to my car to leave to go home and my car did not start again. So I got a jump from a co-worker and went home. This morning I got up about 8 hours after I shut off my car and it started just fine, I started it to make sure it would start. Then about an hour later I tried it again and the battery was so dead that I couldn't even get into the car without popping the hatch and opening the door manually. I charged it again and went to work. I am going to check it again about halfway through my shift to see if it starts.

Finally, what do you guys think could be the problem. The car seems fine as long as it is running but once it sits for an extended period of time it will not start. It is almost like something is draining the battery and it should not be on. BTW, I have not left anything on that should not be, so that cannot be it. Is there a common issue with this problem? If so, could anyone point me in the right direction? I have searched but was unable to find a definitive answer on this problem. Thanks, in advance.

 

Go to the dealer and ask for a flash for DBS (dead battery syndrome). Ever since they flashed my Vette, I've had no problems. I even let it sit for 3 weeks with no problem which shocked me. Before I couldnt let it sit for more than a couple days.

They will charge you a $100+ for the flash though. Worth the hassle to me.

 

Well, as you say, obviously something has started to draw the battery down after the car is shut off. You or a mechanic need to do some diagnosing, a battery draw test when the car is off.

Good luck.

 

Do you know what exactly happens when they do a flash? $100 is well worth it having the peace of mind that my car will start. I just don't want my tune getting screwed up.

 

The flash is more important than the tune. Have the flash done and then have the tune checked.

 

They access the cars computer port and upload a software program fix.
I believe that it will erase the tune, so that might have to be redone.

There is a way to avoid DBS with out doing the reflash. But it's a hassle.
What you need to do is slow your exit from the car.

Turn off the car while in reverse and then take your time and shift into neutral. Then exit the car, and make sure that you don't get the 'shift to reverse' DIC message. Or the 3 honks. Otherwise back to reverse again for a few seconds to let it register. You can actually leave the car in any gear at this point in time. This worked for me for over a year before GM had the solution and fix.

 

I will have to try this. Thanks for the help.

 

Update:

I did an experiment with my car since I was still having issues. I shut my car off, put in reverse, opened my door and set the keys on the ground. That way my car would think I was out of it. I sat there and listened and looked to see of anything stayed on. It turns out my nav/radio was not completely turning off, I can only explain it as a hum or a fan running. So, I pulled the fuse to the stereo and let it sit overnight. When I got up 9 hours later my car started up and held 14.1 volts at idle. So I believe it is fixed other than my stereo does not work unless I put the fuse back in after I start the car, lol. Does anyone know how to get the stereo to go back into "sleep mode" after the car is off? I will admit idk a whole lot about electronics.

 

Did you wait and listen for 10 minutes after closing the door? Supposedly the car will shut these things down after 10 minutes. Like the glove box light. But with the door open, I don't know...

 

I would be surprised if that is the problem. Many owners report a noise from that area. Keep in mind that accessories should shut off after 20 minutes. The flash is worth the piece of mind knowing that the problem will be taken care of.

 

In response to your valid points. I parked the car with the windows down, so that I could lean in the car and listen without the key fob being anywhere near the car. I waited an hour and went back out to the car. It was still making the noise. It doesn't make sense to me either. But for about two days since I have pulled the fuse I have not had an issue with my car not starting.

However, I do agree that that the flash is worth it. It is kind of dumb to be taking the fuse in and out everytime I start and turn the car off. But it seems to be a fix until my tuner is back in town to re upload my tune when I do the flash.