boohame

For the past 6 months I've been battling what I thought was faulty batteries, or an amp or other electric device draining my battery. Currently I'm on the third replacement. But now I'm starting to think it's something else. I'm not too knowledgeable on the electrics on cars yet, so I need you guys help!

Now, what's wrong:

I go to start the car, and it's pretty much dead, engine will barely turn over. So I jump it, and leave it running to charge the battery, shut it off, and come back an hour later to check if it's still charged, and it is. Then somewhere between usually 5 hours it goes 'dead' again.

But today's happenings got me a bit confused...

I go to start the car after it sitting for 24 hours, and it starts fine, but I forgot to choke it so it died after about 10 seconds. I wait about 5 seconds, and try to start it again. What do I get? A lifeless moan from the engine, again. So I checked the battery with a meter, and it's reading full charge. So now this has me thinking it's something other than the battery, but what is it? Alternator? Wiring?


Thanks!

Rx-7Doctor

iTrader: (13)

Just because a battery reads 12volts or more does not mean that it is good. Amps are what is need to start the car. You need to have the battery and alt tested for amperage output by a competent shop. Or if you have a parts store that does testing on the car.
As far as a drain you still might have one and this needs to be tested by a shop since you are not familar with electronics. Also the alternator may be charging but have bad diodes.
Also need to make sure your cables are clean inbetween the posts and battery and that the grounds are clean and tight.

boohame

I had the battery tested where it came from, autozone, and they said it's fine. Whether that's right or not is debatable...I will have it checked somewhere else.

I'm familiar enough with electronics that, though, that I've installed the stereo, and ignition, but I admitedly don't know everything. But I know enough to check for drains and I'm relatively sure that's not it. Almost everything that isn't needed to start or run the car is disconnected at this point.

But that brings up another point, could it be my aftermarket ignition?

And everything is seemingly fine with the connections.


Also, will an alternator from a -SE 13b work on a 12a without modification? Because I have one laying around that I could bolt on there to see if that fixes my problems.

Rx-7Doctor

iTrader: (13)

what you can do , is have someone attempt to start the car while you have the volt meter hooked up and see where the voltage goes. If it does not drop less than 10.2 volts then there is still a chance that the battery is good.
As far as drains go, you are allowed 125 milliamps or 1/4 volt when the key is turned off. You have to tap into the positive battery cable to check this.
As far as your ignition goes, did the problem start AFTER you did this?
And the Se alt will fit, i believe the difference is with the spacer on the longs bolt at the bottom. The connectors are the same.
You also could have a starter that is drawing too much and destroying the battery.
How long before the starting problem occurs inbetween battery charging/changing?

boohame

I'll check both of those.

I installed the ignition and stereo at the same time, and everything was fine for about a month, then it suddenly started happening for months on an off. Then for about 3 weeks everything was fine, no problems at all, then a couple days ago it started in again. But usually before, when I'd charge the battery it would last about a day or so before going dead again, which made me think it was a slow drain. But now that this latest leg of the problem has started, the battery lasts no longer than an hour. But also, like I said before, it started the car fine earlier after sitting about a day, but the car died do to not being choked, and upon trying to restart 5 seconds later, it had the no power problem.

GavinJuice

there is no reason for your car to initally start strong and then a second later not. you have a bad ground or very corroded battery terminals. look at your battery terminals to verify the corrosion, baking soda and water will clean that up. To check for bad ground look at the ground wire from your battery, is it a black wire with a yellow line? If so its the stocker aluminum wire and it needs to be replaced. Replace it along with your positive battery wire at a 4gauge minimum, should be sufficient. Also make sure to clean up your contact points for your grounds and depending on the type of battery terminals and wire you have, you can always run another ground to say the shock tower. Good luck

GavinJuice

a good way to visually check for a drain is to place a light in between the battery ground wire and the battery terminal. Any 12volt light should work. Then start pulling fuses one by one, when your light goes out, you know you have found your problem and you can start backtracking from there. Also, your radio fuse will pull a few milliamps all the time to retain the settings, your drain if it is sounds much more than that.

boohame

The battery is only a couple weeks old, there's nothing wrong with it corrosion wise.

I'll look into that as well.

Thanks for all the info guys.

Rx-7Doctor

iTrader: (13)

Gavin, alittle correction on batteries. They have a reserve capacity. Even when the battery has been discharged if it sits for awhile the chemical reaction or acid reabsorbation process takes place and can be enough to start the car. But then that reserve is gone and now it will not restart. The same thing can happen with a battery that is defective,IE, bad cell. There is just enough to start the car then once it is shut off there is nothing left in the battery. In cases of dead cells the charging system will keep the vehicle running but cannot put a charge into the battery.

1985GSL

iTrader: (4)

I had that problem yesterday acually and i did exactly what Gavinjuice did but with an Amp Meter between the battery post and the battery wire and started pulling fuses. As soon as I found the fuse i figured out what did not work when the fuse was out then put it back and unplugged the things that were off when the fuse was out. It ended up being a defective CD player faceplate. The draw should only be about, .04 amps or less.(mine was at least)

Thousandaire

I've been having a similar problem, check for a faulty ground to starter, also, and i saw it on this site somewhere and came back to find the post, the wirng is corroded and cant carry the load needed. it is apparently becoming a fairly common problem for theses 20+ year old cars. hopefully this post i'm looking for will address the problems

DriftFB

My buddy was having some problems just getting his car to run, we pulled the sparkplug wires one day and, as soon as they popped off the sparkplug, dust came out of the wire. Heat, time, and electrial current turned the wiring into dust.

Something like this might have happened in one of your grounding wires and that might account for the iffy starting. Bad thing is that this would be a hard one to test on all of your wiring.

jgrewe

iTrader: (1)

I once had a battery that tested fine but it turns out the post that you hook the cable to was broken off on the inside of the battery. It would show good voltage but it couldn't supply the amps needed to start the car. It would work sometimes and even show 'good' on a load test but then act totally dead other times. My father in law had worked on the car when I was out of town trying to remove the battery to test my wifes van. He had pried on the terminal trying to remove the cable and broke the post.
You can do a quick alternator test by seeing if the center of the back of it is magnetic while the engine is running. Magnetic=working, but no idea what the voltage being made is.