Hi guys first post here, 1987 ta 305tpi auto, car keeps killing batteries, can't even be recharged in or out of vehicle. Obviously I tested the alternator, checked out OK at 2 different places. When the car was running I noticed the voltage was low around 12 with no load. Help please could there be a short in the charging or starting system. Thanks

 

Maybe a dumb question but you're not using the cheapest parts store batteries/alternators are you? I've had bad luck with those in the past. However, it sounds like a charging system problem, usually charging voltage is around 14-15 volts with the engine running. All connections are good I presume?

 

I don't think it has anything to do with the "cheap parts store batteries and/or alternators" (assuming you checked the battery and alternator). That's all I've ever used in all my cars and I've had quite a few, but anyways Check all your lights and make sure they're ALL off, you could have a deffective switch somewhere. Also, check to see if you have any "aftermarket" accesories like CD players, amps, fog lights, etc. that may have been wired wrong and could be draining your battery. Check for suspicious looking relays too. Just a few ideas here, good luck.

 

Good call on the parasitic draw, that slipped my mind - but I did go through three Oreilly's alternators on one car, and after the third it never had a charging issue ever again.

 

Wow, I guess I've just been very blessed. You never know, maybe that's his problem. Like I said, we're assuming he's checking the battery and alternator professionaly.

 

Thanks for the replies, I've went through 2 brand new batterys, but would a parasitic draw cause a battery to die in 2-3 days, I mean it's completely dead, the battery wont even charge, I've been working on cars for over 25 years, and never encountered this, I plan on testing every circuit wire by wire, batterys are getting expensive. Thanks again. Excellent website by the way.

 

I have been going through the same problems I've been through so many batteries and alts that the local parts stores are refusibg to take them back saying its my car not there parts 4 batteries and 3 alts. I also have low voltage when driving and when I turn on my heat or lights the voltage drops to 10 to 12 alt least 2 volts each accesory. Ivr changed every lead ground and relay I can think of still same problem. Last night I noticed tghat when I connect the batt ground my headlight motor makes a noice so I disconnected the motors brand new battery we will sii if that's the problem. Keep us informed and ill do the same we may need to talk on the phone maybe between our experiences with this problem we can save a headache lol

 

Sounds good infrared, I was going through the post's and it seems to be a fairly common problem. I'm going to try a few things over christmas, I've got a new main cable {battery to starter} and check for short circuits, I'll let you know how it goes, thanks and keep in touch

 

If it's taking 2-3 days for battery to drain, it's a longshot, but ....

see if the fuel pump is running with the key out of car. The fuel pump is powered by the oil pressure sending unit, and the OPSU can go bad and 'think' it's getting oil pressure when it's not. Since the OPSU has a direct connect to the battery, it can make the fuel pump run regardless of the key.

 

If its winter, and the battery becomes discharged, it quickly sulfates, and becomes useless. Doesnt take much time once the voltage falls to around 12V. I have a junker sitting around that does the same thing. The radio wont shut off as the accessory in the ign is permanently stuck on. In about two or three days, it kills the battery if you dont disconnect it.

They can sometimes be salvaged if theyre new by carefully overcharging them with 16V or so, which drives the sulfate off the plates and renews the battery. Puts some wear on the plates, but its better than trashing it. Some chargers will do this automatically if they have a desulfate feature.

 

Don't know if it's related, but the fasten seat belt light comes most of the time even when i'm wearing it

 

I just got a 1989 RS running and began to go through all the lights. One tail light bulb, a handfull of instrument cluster lamps, passenger side low beam headlight, cargo hatch courtesy lamp and, last but not least, the under hood courtesy lamp were all out.

The under hood courtesy lamp got me. I did not realize the switch didn't work to turn off this lamp when the hood is closed. Next morning the battery was graveyard dead.

If you haven't checked already, I'd recommend checking that this lamp, if present on your car, isn't staying on all the time. It will definitely kill a battery in a few hours.

 

Something else to check, because this is what killed my battery - if you have an engine ground strap attached to your firewall, check that it's not rusted... if your engine needs one and it's not functioning, that'll keep your alternator from charging your battery when you're driving. I had this problem for months before I figured it out when I saw sparks coming from the engine side of the firewall when I had my dad start the car with the hood open.

 

ok i pulled all the fuses, pulled the negative battery cable and im still getting a draw. I then pulled the wires off the started execpt the top drivers side post wires on the alt..still getting a draw on my ohm. Now i think i found the problem but dont know how to fix it...please help
the p.o. put a one wire car. the brown wire and the red wire that was connected to the alternator have been cut. However they are still getting 12 volts!! both wires brown and red. Are these two wires possibly connected to the starter? and if so can i just remove them from the starter and not loose power to anything else such as headlights heater and signals? I know the brown wire is supposed to go to the dummy light but why would it have constant power? and the red wire must go to the starter? What do you guys think? I have 2 days to get this car on the road