Low Volts?
Thread Starter
Heel & Toe
Joined: Jun 2008
Posts: 16
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From: 86 roadster,Toronto Can
Low Volts?
The last few days the volts meter on my 86 has been hovering around 10.9-11.0 with the red caution lamp on. With a new delco battery installed, I'm thinking its the alternator on its last breaths. Yesterday while driving the meter sudently started dropping untill it was about 7.5 and the car started sputering, and everything (instrument panel) went black and finaly stalled right on the highway exit..scary!
About 3 boosts later and along the way got me home. Any experience and thoughts on this problem is appreciated
About 3 boosts later and along the way got me home. Any experience and thoughts on this problem is appreciated
Last edited by jimmieM; Jul 1, 2008 at 01:27 PM.
Thread Starter
Heel & Toe
Joined: Jun 2008
Posts: 16
Likes: 0
From: 86 roadster,Toronto Can
Randy93, I should of mentioned, the car has been parked for a few years with the new delco battery installed a few months ago once out of storage with the car's volts reading about 14.4 and running great the last few months untill the volts incident described above... so I don't think it's the battery, but then again it may be even if it's new..
Team Owner
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Check alt output post to battery ground post, see what its reading. If its low then the alternator isnt putting to the battery.
If you placed neg VM probe on the negative batt cable, then you could have a defective batt neg cable or bad connection between the batt cables and batt posts.
Find the alternator output wire where it comes up to the bolt behind the battery (8 large red wires attached) and engine running feel the temp of the fusible link, shouldnt be hot.
If you placed neg VM probe on the negative batt cable, then you could have a defective batt neg cable or bad connection between the batt cables and batt posts.
Find the alternator output wire where it comes up to the bolt behind the battery (8 large red wires attached) and engine running feel the temp of the fusible link, shouldnt be hot.
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From: Toronto(Don Mills) Ontario
Randy93, I should of mentioned, the car has been parked for a few years with the new delco battery installed a few months ago once out of storage with the car's volts reading about 14.4 and running great the last few months untill the volts incident described above... so I don't think it's the battery, but then again it may be even if it's new..
Yes it could be! I had a new premium Delco in my L86, and all of a sudden it started exhibiting similar symptoms, i.e.- no start 'out of the blue',low voltage, inability to take a fresh charge, etc. Turns out my new Delco had a bum cell(out of the 6)! Battery was only 2 years old! Probably a crack/defect that shorted out the one cell - which crippled the battery, in effect. New cheapo Kirkland(from Costco!) fixed the problem immediately! 
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....like everyone said...
1...measure voltage at battery terminals...should be just above 12vdc.
2...measure voltage from red wire at alternator to ground (should be
above 12vdc. if not (no voltage reading), you have bad fusible link
(or broken wire) which killed the power to/from the
alternator/battery.
3...start the car any way you can and measure voltage at the
alternator red wire to ground (should be at least 13vdc). if not,
alternator is BAD.
4...measure voltage at batery terminals again. (should be just about
the same as in #3). if not, you have a wiring problem or blown link.
5...if battery keeps dying, you most likely have a shorted battery
cell(s) or a heck of a battery drain someplace.
1...measure voltage at battery terminals...should be just above 12vdc.
2...measure voltage from red wire at alternator to ground (should be
above 12vdc. if not (no voltage reading), you have bad fusible link
(or broken wire) which killed the power to/from the
alternator/battery.
3...start the car any way you can and measure voltage at the
alternator red wire to ground (should be at least 13vdc). if not,
alternator is BAD.
4...measure voltage at batery terminals again. (should be just about
the same as in #3). if not, you have a wiring problem or blown link.
5...if battery keeps dying, you most likely have a shorted battery
cell(s) or a heck of a battery drain someplace.
Thread Starter
Heel & Toe
Joined: Jun 2008
Posts: 16
Likes: 0
From: 86 roadster,Toronto Can
Thanks to all!!
I'm sure it's the alternator due to the fact that when the car stalled the battery would bounce back up a little while the car sat waiting for another boost to make it home.
It took a total of 4 boost for about a 5 km ride back home, and while on the cables from the donor car the volts would climb.
I'm sure it's the alternator due to the fact that when the car stalled the battery would bounce back up a little while the car sat waiting for another boost to make it home.
It took a total of 4 boost for about a 5 km ride back home, and while on the cables from the donor car the volts would climb.
Last edited by jimmieM; Jul 2, 2008 at 02:26 AM.