I just thought I'd throw this by you guys since I've been having the problem for a couple years and it never hurts to ask. This is an 87 camaro, tuned port injection. Every mechanical part in the car has been replaced, but the problem persists. I've even replaced all of the accessories with a serpentine system, and the engine is also new.
What happens is that when the car warms up, the voltage at the guage drops almost to the red and this results in the turn signals slowing down. Now if you connect a voltmeter at the alternator it shows 14.8v, and the battery shows 13.8, so the guage is not reading correctly, but the blinker speed being affected does suggest that something else is wrong. The car has a drain that I haven't been able to hunt down, but it will completely drain the battery in 3 days(I've installed a key to disconnect the negative cable when the car is off to prevent this). Now this doesn't really cause any problems--I did have a string of dying batteries and alternators due to the stress from the drain, but that has been taken care of mostly by the switch--but it is the last thing I need to do to make the car perfect.
Anyone fixed a similar problem, or have any ideas besides finding the drain? I'll get to it when I have time, I don't know if it's associated or not. (it may be from my stereo, but like I said I haven't had time to check it out)

 

thats wierd does it ever blow a fuse anywhere? relays look burnt>?

 

start pulling fusees one at a time till the battery stays up then at least you'll know what circut to look at. might want to invest in a short finder.

 

Or you can use an analog or digital ammeter that has a 10A scale. Connect the meter as instructed, then remove fuses/loads one at a time until you find a significant change.

As for the voltage differential between the alternator and battery, there shold be alomst NO measurable difference. If there is, you have a connection problem somewhare. Just for grins you can measure voltage from the alternator case to the battery negative to see if there is any potential - there should be 0 volts. You can do the alternator output and battery positive in the same way, but your measurements already indicate a 1.0V drop, and that's a problem.

 

I know you guys get tired of hearing me beat the same drum, but, any time you have a slow battery drain that takes about 2 or 3 days the first thing to check is the hatch pull down, if it is jammed or damaged it will continue to pull power and will not blow the fuse. disconnect the hatch pulldown motor in the back and see if that helps the drain.

 

OR,
Make sure everything is off, and the doors are shut. Make sure the interior light (and underhood light) cannot come on when the door (or hood) is opened. Remove bulbs if necessary. Disconnect negative battery terminal.
Connect red lead of digital multimeter to disconnected negative battery terminal and the black one to the negative battery terminal itself. Set meter to mA setting. If it reads 0.05 A (50mA) or more then excessive current leakage is confirmed. Then do what Vader says and disconnect everything you can (including alternator) until the meter reading drops. Confirm what that circuit controls and move your investigation there.

Andy.

Obvious statement here
You have checked the tailgate bulb isn't staying on? But this wouldn't effect the voltage at the battery being different from the alternator though.

 

No fuses or relays are bad. The pull down isn't coming on, no lights stay on.

I was told that the 1 volt difference between the alt and battery was normal, so I didn't see that as bad. I guess I'll keep this thread linked for when I have time to look into it later. I know how to search for the draw, but at the moment studying is more important. Thanks guys.

 

My 86 does that. I'm convinced its the wiring, since everything else is new. I suspect if you replace the wires and make sure all the grounds are good, the problem will go away. I know that the wire from the alt to the battery and the ground from the battery to the block have some corrosion. Its not visible, but I know if I cut the wire apart I'll find it. I can hear it when I move the wire around, theres stuff in there that shouldnt be in there.

 

Sounds to me like you should just give your car to me.!


Try checking your starter solenoid or the fuseable link

 

My '88 has developed a similar problem.
I hadn't driven it in 6 months and now that I'm driving it again the battery drains down in a few days.
My alternator is putting out 13.8 volts, havn't checked yet to see what the battery gets of that.
I think in my case, its a combination of wiring problems and a crappy old battery.

 

Here is another vote for the hatch pull down. Just cause you don't hear it doesn't mean it is not trying. When you close it do you here it click when it stops pulling or does it just stop. Mine was doing the same thing. I loosened the three bolts and move it up slightly so it could secure it and stop pulling down. Disconnect it and see if the problem persists.

 

Come to think of it, I can't remember if the '88 "clicks" or not when it pulls the hatch down. I know the '92 clicks loud enough to hear.
I have something to check!

 

It clicks. I always help the motor close it because in my mind I think that will make it last longer for some reason, so I always hear it. I think if I replace the positive cable it may help, but whenever I go into an auto parts store I think to myself, "damn, I should have measured that thing" and don't know which to buy. This isn't just something that you disconnect and see if it goes away, because that would end up with me buying a new battery and possibly alternator if it wasn't the problem, although I thank you for the suggestion I wasn't aware that so many people had hatch pull-down problems. I'd guess at least some of those would be from improper adjustments.

 

Change this to an '87 GTA and this is EXACTLY, I mean exactly the problem I have been having for the past year and a half or so. Exactly. Good voltage output, but blinkers slow down, headlights go dim, and battery drains inside of 5 days. That is wierd. Exactly the same problem I have. I've tried pulling fuses to no avail. Fusible links look fine/no corrosion and no voltage drop through the link... We have to peg this problem