Help- Draining Power While Driving
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Joined: Jul 2005
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From: Dexter Michigan
Help- Draining Power While Driving
Ok, I hope someone can help me with this. Installed a new battery, and took my 84 out for a drive. I was losing volts faster than I could watch! I was between 11.5 and 12 on my way out the door. By the time I got home from my 10 mile drive I was around 8!! What the heck would cause that?? Alternator?? Somebody please help me. I can't take much more of this.
Le Mans Master
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From: Woodstock Georgia
You were lucky to get it home, by rights at that low a voltage reading it should have quit. Charge the battery back to full charge and if there is an auto parts nearby drive it to them for a free alternator check.
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From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
Originally Posted by aminnich
You were lucky to get it home, by rights at that low a voltage reading it should have quit. Charge the battery back to full charge and if there is an auto parts nearby drive it to them for a free alternator check.
Alternator check is in order and most auto stores will do it for free! It is not recharging your battery and thus the new one is being sucked dry(Whew!) of juice(Dang!). A new alternator is probably in line!Let us know what you find out after the test!
Thanks,Matt
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From: Cincinnati, Oh USA
Car batteries are considered discharged when their terminal voltage falls to 12.0 volts or below. If your alternator is not charging the battery, you should notice the red battery symbol light on the dash lit up! Normal operation is to see 14.3 volts on the dash voltmeter when the alternator is cold and this normally drops to 13.3 volts alternator hot. You have symptoms of a defective alternator. If it tests ok, then you likely have the fusible link in the alternator output wire that is blown and is open circuit. The voltage on the alternator output terminal should be identical to the battery terminal voltage and if the alternator measures 14.7 and the battery considerably lower (like 12.5 volts), then the alternator link is blown and should be replaced.
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From: Down East NC
To just add a bit: I just had the alternator on my 87 rebuilt, voltage was dropping and the battery indicator light was on. Autozone tests them but of course all they're interested in is selling you a new one, which is actually rebuilt anyway (probably poorly) with some aftermarket housing, etc. and to save the core charge you'll be tempted to trade in yours as a core. I had mine rebuilt by a local shop for $59, all that was wrong with it was the bridge, and that's all he charged me for along with labor.
I learned this lesson with my old 84 Z28's starter some years ago, turned it in and the autozone rebuilt unit just didn't quite ever fit right and I ended up having to go to a local shop where they found me an oem housing and built me a new one. Since then, any starter/alternator trouble I always have my stock unit professionally rebuilt. Just my .02-
I learned this lesson with my old 84 Z28's starter some years ago, turned it in and the autozone rebuilt unit just didn't quite ever fit right and I ended up having to go to a local shop where they found me an oem housing and built me a new one. Since then, any starter/alternator trouble I always have my stock unit professionally rebuilt. Just my .02-
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Joined: Jul 2005
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From: Dexter Michigan
JFB, that's interesting about the alternator link being blown, I am swapping the alternator out tonight and will take a look at how the "new" one reacts. How difficult would it be to change the alternator link out? I am by no means a mechanic but prefer saving dollars whenever possible.
thanks for the input desino614, i will keep this in mind also.
thanks for the input desino614, i will keep this in mind also.
Instructor
Joined: Aug 2006
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From: Victoria BC
Originally Posted by designo614
To just add a bit: I just had the alternator on my 87 rebuilt, voltage was dropping and the battery indicator light was on. Autozone tests them but of course all they're interested in is selling you a new one, which is actually rebuilt anyway (probably poorly) with some aftermarket housing, etc. and to save the core charge you'll be tempted to trade in yours as a core. I had mine rebuilt by a local shop for $59, all that was wrong with it was the bridge, and that's all he charged me for along with labor.
I learned this lesson with my old 84 Z28's starter some years ago, turned it in and the autozone rebuilt unit just didn't quite ever fit right and I ended up having to go to a local shop where they found me an oem housing and built me a new one. Since then, any starter/alternator trouble I always have my stock unit professionally rebuilt. Just my .02-
I learned this lesson with my old 84 Z28's starter some years ago, turned it in and the autozone rebuilt unit just didn't quite ever fit right and I ended up having to go to a local shop where they found me an oem housing and built me a new one. Since then, any starter/alternator trouble I always have my stock unit professionally rebuilt. Just my .02-
Le Mans Master
Joined: Jan 2006
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From: Woodstock Georgia
Originally Posted by vettesareme
Hey Guys??? Where did everyone go???
In case you haven't heard of a fuseable link before it it built into the cable and engineered to 'fail' just like any fuse in order to protect the circuit from damage, in this case burning wires.
Last edited by aminnich; Aug 3, 2006 at 09:32 PM.
Racer
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From: Miami FL
Originally Posted by aminnich
Here. So alternator checked good and new battery, yet voltage drops badly while running. Correct so far? Check positive cable from alternator to battery for continuity. I am not familiar with your year, but understand there is a fuseable link in the cable, and if it 'melts' then the alternator can not do it's job as it is not connected to the battery.
In case you haven't heard of a fuseabler link before it it built into the cable and engineered to 'fail' just like any fuse in order to protect the circuit from damage, in this case burning wires.
In case you haven't heard of a fuseabler link before it it built into the cable and engineered to 'fail' just like any fuse in order to protect the circuit from damage, in this case burning wires.
with all of the above.
Le Mans Master
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From: Woodstock Georgia
Originally Posted by vettesareme
OK Great! Thanks aminnich! I was starting to feel all alone out here 
So I should just try changing the battery cables?
So I should just try changing the battery cables?
Racer
Joined: Apr 2006
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From: Kelso WA
Nobody's mentioned making sure the battery connections are clean. If you have the old style battery with the connections on top, make sure the inside of the cables that clamp on to the battery connectors are clean.
Le Mans Master
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From: Woodstock Georgia
Originally Posted by bsmutz
Nobody's mentioned making sure the battery connections are clean. If you have the old style battery with the connections on top, make sure the inside of the cables that clamp on to the battery connectors are clean.
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From: Dexter Michigan
Ok, Sorry everyone. I haven't had a chance to do anything else. I did check the alternator first before buying anything aminnich. Not sure exactly what to do with the fusable link. The car does start but sometimes (from such low voltage) it cranks hesitantly. The cables seem to be relatively new, not sure how to change this out. I did ,however, look up the fusable link and was able to find it but like I said I'm not sure what to do with that. It has a side post style battery. I'm trying to give you as much info as I can.
Le Mans Master
Joined: Jan 2006
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From: Woodstock Georgia
Originally Posted by vettesareme
Ok, Sorry everyone. I haven't had a chance to do anything else. I did check the alternator first before buying anything aminnich. Not sure exactly what to do with the fusable link. The car does start but sometimes (from such low voltage) it cranks hesitantly. The cables seem to be relatively new, not sure how to change this out. I did ,however, look up the fusable link and was able to find it but like I said I'm not sure what to do with that. It has a side post style battery. I'm trying to give you as much info as I can.