Calling all electrical experts
Melting Slicks
Joined: Aug 2004
Posts: 2,165
Likes: 950
From: Keizer Oregon
Originally Posted by BKbroiler
First - thanks for all the advice.
Now the latest - Was a nice day today, so I started the car, no problem. Drove around for 45 min, speeds up to 80 at times so the alternator was spinning. Volt gage in car stayed over 13. Got home, shut it off, wouldn't restart. Cranked VERY slowly. I decided to retard the timing and try again. Made no difference. Let the car cool for 2 hours. No change. Battery voltage was reading 12.5. Checked voltage at the starter - 12.5 also. Changed starters - put my old 20 pound unit back in - no change - still cranked slowly. Decided to charge the battery. The charger indicated battery voltage as 13.0 when I started. Checked back in an hour, charger said FULL. Rechecked battery voltage, now 13.5 with my voltmeter. Guess what - now the car starts normally. I think, as a lot of you suggested, the nine month old battery is bad.
Now the latest - Was a nice day today, so I started the car, no problem. Drove around for 45 min, speeds up to 80 at times so the alternator was spinning. Volt gage in car stayed over 13. Got home, shut it off, wouldn't restart. Cranked VERY slowly. I decided to retard the timing and try again. Made no difference. Let the car cool for 2 hours. No change. Battery voltage was reading 12.5. Checked voltage at the starter - 12.5 also. Changed starters - put my old 20 pound unit back in - no change - still cranked slowly. Decided to charge the battery. The charger indicated battery voltage as 13.0 when I started. Checked back in an hour, charger said FULL. Rechecked battery voltage, now 13.5 with my voltmeter. Guess what - now the car starts normally. I think, as a lot of you suggested, the nine month old battery is bad.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Well I had the battery load tested today and the verdict was that the battery is OK. So, as a sanity check, tomorrow I will switch batteries with another vehicle and do a drive and restart test. That will prove if the battery is the culprit.
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
Originally Posted by BKbroiler
So, as a sanity check.....
Additionally, put a VOM across your battery posts and read voltage...record what it is engine off...with VOM still attached, start car...if voltage goes up, it's very probably not the alternator...
Team Owner
Joined: Jun 2001
Posts: 23,367
Likes: 1,061
From: Virginia USA
Since you are saying your battery has checked good and your alternator checks good I would check the ground wires going from your battery to the frame and your ground wire going from the engine block to the frame. I had a similar problem ( not dying during driving but dead battery after only a few days sitting) and my battery ground cable was not making a good connection. Once I cleaned that up my battery drain problem went away. I've found on these cars that I always check the grounds first. I bet 6 out of 10 electrical problems are ground related. Good luck.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
kb2fzq - I've done the voltmeter test. 12.5 engine off, 13.5 engine running.
theandies - Ground wires, interesting. I did check the heavy negative bat cable connection on the frame. Cleaned it up, no help. However, I don't think I have a ground connection from the engine to the chassis. Could that be the problem? (I posted this question as a seperate thread also, before I saw your response here.
theandies - Ground wires, interesting. I did check the heavy negative bat cable connection on the frame. Cleaned it up, no help. However, I don't think I have a ground connection from the engine to the chassis. Could that be the problem? (I posted this question as a seperate thread also, before I saw your response here.
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
You have to have a ground from frame to chassis or the starter wouldn't turn....right?...pos/neg theory...right?
Find that, clean it, or put in a new cable...I can not help, don't know where that connection is, but I know there has to be one...I've also heard there is a starter ground cable which is an ehgine-->chassis ground in itself...maybe that's the eng to chas ground...with a jumper cable you should be able to check alternator efficiency....volt meter neg on engine, pos on battery pos...low or no change in voltage engine on/off would tell me the engine ground is bad...you can also check ohm differntial from bat neg to engine...if there is resistence...bad ground..
I hope you find the problem...I hate these types of problems...
Find that, clean it, or put in a new cable...I can not help, don't know where that connection is, but I know there has to be one...I've also heard there is a starter ground cable which is an ehgine-->chassis ground in itself...maybe that's the eng to chas ground...with a jumper cable you should be able to check alternator efficiency....volt meter neg on engine, pos on battery pos...low or no change in voltage engine on/off would tell me the engine ground is bad...you can also check ohm differntial from bat neg to engine...if there is resistence...bad ground..
I hope you find the problem...I hate these types of problems...
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by oregonsharkman
Yep...most likely.....check out optima yellow top....
Team Owner
Joined: Jun 2001
Posts: 23,367
Likes: 1,061
From: Virginia USA
Originally Posted by BKbroiler
kb2fzq - I've done the voltmeter test. 12.5 engine off, 13.5 engine running.
theandies - Ground wires, interesting. I did check the heavy negative bat cable connection on the frame. Cleaned it up, no help. However, I don't think I have a ground connection from the engine to the chassis. Could that be the problem? (I posted this question as a seperate thread also, before I saw your response here.
theandies - Ground wires, interesting. I did check the heavy negative bat cable connection on the frame. Cleaned it up, no help. However, I don't think I have a ground connection from the engine to the chassis. Could that be the problem? (I posted this question as a seperate thread also, before I saw your response here.
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