Guest Ansis42 Posted May 26, 2015 Share Posted May 26, 2015 I am having an interesting problem with my 1980 Buick LeSabre. 4.9L 301. I have just gotten my Buick back on the road after tearing apart the engine to replace the Head Gaskets. I also had to replace the starter and the battery. The new battery sat unused for a while, and eventually lost it's charge. The Buick would not start because of the low battery. So I attempted a jump start, and it started right up. However, a few seconds after I took the jumper cables off the battery in the Buick, the engine died. I tried this a couple more times. Each time, the engine died seconds after taking off the jumper cables. So, I took the battery into Advanced Auto. They charged it up for me. While I was there, I decided to have the alternator tested. They said the alternator was just fine. After the battery was fully charged, I was able to consistently start the engine. Each day, I would start it up, and simply drive it around my neighborhood for a few minutes (I wasn't brave enough to take it out on the open road, for fear of it dying). In hindsight, each time I started the engine, it seemed to crank a little bit slower than before. I didn't think anything of it at the time. However, one night, I decided to nut-up and take it down to the gas station to fill it up. I put gas in it, tried to start it up......nothing. It cranked VERY slowly, and never started. I had to have my girlfriend come give me a jump. The Buick started up, but on the way home, I could tell the power was slowly fading. When I got home, I turned the engine off, then immediately tried starting it again. As I expected, it gave a slow crank, but did not start. So, normally I would think this is caused by a bad alternator. However, they tested it and said it was fine. Should I take the alternator to another place for a second opinion? Or maybe see if there is a problem with the wires connecting the alternator to the battery? Thank you for any help you can provide. Link to comment Share on other sites More sharing options...
MCHinson Posted May 26, 2015 Share Posted May 26, 2015 Have you tried measuring the voltage at the battery terminals both while the car is running and when it is not running? I would test and compare the voltage while running versus while not running. That will tell you if the battery is actually receiving a charge from the alternator. If the voltage is the same, it sounds like either the alternator or some wiring is an issue. Also, while parked, are the headlights dim or bright? I once had a car that acted like the battery was weak but it was actually a bad starter and the battery was actually fine. Link to comment Share on other sites More sharing options...
Guest Ansis42 Posted May 26, 2015 Share Posted May 26, 2015 Have you tried measuring the voltage at the battery terminals both while the car is running and when it is not running? I would test and compare the voltage while running versus while not running. That will tell you if the battery is actually receiving a charge from the alternator. If the voltage is the same, it sounds like either the alternator or some wiring is an issue. Also, while parked, are the headlights dim or bright? I once had a car that acted like the battery was weak but it was actually a bad starter and the battery was actually fine. I'll get the battery charged again and check the volts. The headlights were dim, but I think that's because the battery was losing it's charge. I just replaced to starter, so I'm certain that isn't an issue. Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted May 26, 2015 Share Posted May 26, 2015 Sometimes batteries get so weak that they just cannot hold a charge. Sulfated cells, etc. Long term siting has killed batteries for me until I purchased a tender for each car. Now Batteries seem to last 5-6 and more years. Link to comment Share on other sites More sharing options...
Guest Ansis42 Posted May 26, 2015 Share Posted May 26, 2015 Sometimes batteries get so weak that they just cannot hold a charge. Sulfated cells, etc. Long term siting has killed batteries for me until I purchased a tender for each car. Now Batteries seem to last 5-6 and more years. What is a tender? The battery isn't very old (only about 6 months). I suppose even though the battery is chargable outside of the engine, there may be some fatal flaw within that is only surfacing when running in the engine? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted May 26, 2015 Share Posted May 26, 2015 Sounds to me like the alternator is not charging the battery. It could have failed since you had it tested, or it has an intermittent fault, or you have faulty or corroded wiring, lots of things could be wrong. But I would concentrate on the alternator and wiring. Quick test to tell if an alternator is working. With the engine running touch the back of the alternator in the center with a screwdriver. If it is working you will feel a magnetic pull. If it is not working you won't. An alternator creates a magnetic field as it works. Link to comment Share on other sites More sharing options...
cahartley Posted May 27, 2015 Share Posted May 27, 2015 With the engine running pull a cable from a battery post.If it doesn't keep running your problem is before the battery.If the battery went completely dead it may be shot.A long, SLOW, charge might bring it back....... I'm betting on not.Did they do a draw test on the battery? Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted May 27, 2015 Share Posted May 27, 2015 (edited) A tender is a small battery charger that is used to maintain a battery that is not used a lot or will not be used for a long period of time. When connected to the battery it constantly measures the amount of charge in the battery and when needed charges the battery until fully charged again. You can get them almost anywhere that sell batteries. Another check for your alternator is to use a voltage meter and measure the battery voltage while the car is running. Should read about 14 volts. 12 or less means no current is flowing into the battery. Could be the alternator or a bad connection or wire. Edited May 27, 2015 by plymouthcranbrook (see edit history) Link to comment Share on other sites More sharing options...
Restorer32 Posted May 27, 2015 Share Posted May 27, 2015 You may have an electrical leak somewhere. Turn off everything. Unplug the clock. Close the doors. If there is an under hood light disable that. Unhook a battery cable and touch it lightly against its post. There should be no spark whatsoever. Link to comment Share on other sites More sharing options...
keiser31 Posted May 27, 2015 Share Posted May 27, 2015 Also check the trunk light......those are famous for staying on and draining power. Ask me how I know.... Link to comment Share on other sites More sharing options...
dictator27 Posted May 27, 2015 Share Posted May 27, 2015 Also check the trunk light......those are famous for staying on and draining power. Ask me how I know....Ditto the glove box light. :} Disconnect the battery ground cable, attach a test light to the cable and touch the battery negative post with the test light probe. If it lights up something is drawing current. Remove a fuse. If the light stays on, replace that fuse and pull another one. When the light goes out, that is your problem circuit. Terry Link to comment Share on other sites More sharing options...
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