Charging Problems?
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 33
Likes: 0
From: Baton Rouge LA
Charging Problems?
Hi,
I hope someone will be able to help me on this problem.
I have a 1986 Vette and I'm having charging problems. I will list some history of what I've done to solve the problem.
Back last September I had a problem and discovered that the alternator body was cracked. I went to autozone and found a replacement and everything seemed fine, but now I having probelms again.
The volt meter highest reading was 13.2 volts, but at idle would go as low as 10.1 volts. I had it checked and they said to replace the alternator. I ordered a Powermaster 140 amp. alt. , which is made for Vettes and just now installed it. The voltage is good, but at idle the dash gauge lights are dim and when you rev up the engine, they brighten back up. I had the battery checked back when I had the alternator checked and they said it needed charging and they say it was in good range, but it is 6 years old now. Any ideas would be apprecative. Will low voltage coming from the battery effect gauge readings and/or the computer, possibly receiving codes from the chip or computer which I'm receiving too?
Thanks,
John Young
I hope someone will be able to help me on this problem.
I have a 1986 Vette and I'm having charging problems. I will list some history of what I've done to solve the problem.
Back last September I had a problem and discovered that the alternator body was cracked. I went to autozone and found a replacement and everything seemed fine, but now I having probelms again.
The volt meter highest reading was 13.2 volts, but at idle would go as low as 10.1 volts. I had it checked and they said to replace the alternator. I ordered a Powermaster 140 amp. alt. , which is made for Vettes and just now installed it. The voltage is good, but at idle the dash gauge lights are dim and when you rev up the engine, they brighten back up. I had the battery checked back when I had the alternator checked and they said it needed charging and they say it was in good range, but it is 6 years old now. Any ideas would be apprecative. Will low voltage coming from the battery effect gauge readings and/or the computer, possibly receiving codes from the chip or computer which I'm receiving too?
Thanks,
John Young
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
If you drive your vette frequently the battery should have at least 1/2 its amp-hour capacity. After the battery sits overnight measure the voltage at its terminals, it should be around 12.5 volts. State of charge can be determined by its no load terminal voltage. 12.0 volts and below, discharged, 12.9 volts and above, fully charged and linear inbetween. At 6 years old, I suspect your battery is at the end of its life and has very low amp-hour capacity and is being charged heavily all the time causing low system voltage at idle. You should not experience light dimming at idle unless you have unusual heavy electrical load. Normally, a cold alternator at idle will show a dash voltmeter reading of 14.3 volts and this drops to 13.3 volts when the alternator gets to its operating temp (engine hot). Of course you have to have normal idle rpm and a standard size pulley on the alternator. I recommend a new battery.
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 33
Likes: 0
From: Baton Rouge LA
Dear JFB,
I just went back out and here's some more info. I'm running a std. size pulley, but it is a March pulley.
With key just on the on position,engine off, the volt reading is 11.7 volts. Cold cranking & running the voltage is reading 14.1 then drops quickly to 11.6 to 12.2 at idling @700 to 800 rpms. I can rev engine to 1800 rpm and I get 14.3 volts steady.
So do you still think the battery could be the culprit? Or will driving tell more? It takes my Vette a good while to warm up, for I'm running a modifed engine with extra cooling system like, chip, thermo and 180 degree fan relay.
Thanks,
john
I just went back out and here's some more info. I'm running a std. size pulley, but it is a March pulley.
With key just on the on position,engine off, the volt reading is 11.7 volts. Cold cranking & running the voltage is reading 14.1 then drops quickly to 11.6 to 12.2 at idling @700 to 800 rpms. I can rev engine to 1800 rpm and I get 14.3 volts steady.
So do you still think the battery could be the culprit? Or will driving tell more? It takes my Vette a good while to warm up, for I'm running a modifed engine with extra cooling system like, chip, thermo and 180 degree fan relay.
Thanks,
john
Instructor
Joined: Oct 2004
Posts: 208
Likes: 1
From: Santa Rosa CA
Originally Posted by jfb
At 6 years old, I suspect your battery is at the end of its life and has very low amp-hour capacity and is being charged heavily all the time causing low system voltage at idle.
