mustangman2011 Posted April 23, 2013 Report Share Posted April 23, 2013 I have a friend with a 2004 Chevy Malibu 3.5 LT with charging problems. The battery was replaced about 3 months ago. Eventually it started turning over slowly and now most of the time has to be jumped to start it. They had the alternator checked off the car and it tested ok. With the car running with a volt meter it was barely registering like 12.8 volts. They thought maybe the alternator was going bad slowly so they replaced the alternator.. They also had the battery charged and it tested out good. Any way they went and had it tested on the car and they said was only putting out like 12.87 volts. What else could this be? Thanks Quote Link to comment Share on other sites More sharing options...
Cordell Posted April 23, 2013 Report Share Posted April 23, 2013 Where are they measuring voltage? Across the battery, or at the back of the alternator? Sounds like a possible wiring issue with the alternator leads, but it would need checked out. Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted April 23, 2013 Author Report Share Posted April 23, 2013 At the battery. Quote Link to comment Share on other sites More sharing options...
Cordell Posted April 23, 2013 Report Share Posted April 23, 2013 At the battery. I'd check it at the alternator, excessive resistance between the battery could cause an excessive voltage drop preventing the battery from recharging. Now if the voltage is the same at the alternator the pcm may not be signaling it on or have a broken wire (you know the small wire). Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted April 23, 2013 Author Report Share Posted April 23, 2013 I had them check it they said at idle it was like 13.3 at the back of the alternator and about 13.17 at the battery. Is that normal? Quote Link to comment Share on other sites More sharing options...
Cordell Posted April 23, 2013 Report Share Posted April 23, 2013 I had them check it they said at idle it was like 13.3 at the back of the alternator and about 13.17 at the battery. Is that normal? Yeah above 13 is pretty normal, if they turn on all the electrical accessories in the car and it stays over 13 then the alternator and associated wiring should be fine. What happened to 12.8? What voltage do they measure with the car off? Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted June 18, 2013 Author Report Share Posted June 18, 2013 Well the things randomly dies still. If you jump it starts up right away though. What else could this be? A draw somewhere? Quote Link to comment Share on other sites More sharing options...
Rocky31186 Posted June 18, 2013 Report Share Posted June 18, 2013 Kind of hard to internet diagnose it.. It could be any number of items that need checked. Do you have a DVOM to start checking things? Quote Link to comment Share on other sites More sharing options...
cstmg8 Posted June 18, 2013 Report Share Posted June 18, 2013 Is the battery in the trunk? I had a similar issue, and it ended up being a broken post at the alternative positive under the hood. This is where the alt and battery wires connected. Put my own bolt through them, no more problems. May want to trace down any loose connections. Shaun Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted June 19, 2013 Author Report Share Posted June 19, 2013 Yes Rocky I have a meter to check voltages. What kind of tests do you suggest. Shaun the battery is under the hood not the trunk. I am going to look over the wiring again later today when I have a chance.....thanks Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted June 21, 2013 Author Report Share Posted June 21, 2013 I am starting to think it is either bad wiring and/or a draw. I charged the battery up and it dropped over night about half a volt. Whats a normal acceptable drop if you let a car sit over night etc? Quote Link to comment Share on other sites More sharing options...
Cordell Posted June 22, 2013 Report Share Posted June 22, 2013 It's not damp or wet around the terminals is it? Are you familiar with the term "dark current" where a battery can discharge due to a leak or excessive corrsion? I doubt it considering the stuff was replaced, but at this point you might want to restest the battery. Quote Link to comment Share on other sites More sharing options...
mustangman2011 Posted June 23, 2013 Author Report Share Posted June 23, 2013 No its not wet Cordell. I am really getting frustrated with this. Quote Link to comment Share on other sites More sharing options...
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