System Charging
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
System Charging
I have a 1989 corvette, system is not charging the battery. Replaced
the alternator, had it checked at the store and is good. The battery was also checked and is good. The starter is good, but the system only shows 11 volts when running, then drops off then engine dies. Help!!
the alternator, had it checked at the store and is good. The battery was also checked and is good. The starter is good, but the system only shows 11 volts when running, then drops off then engine dies. Help!!
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
First, you need to charge the battery so that it will show something like 12.6v or more.
Then, with the engine running, what is the voltage at the large terminal (red wire) on the alternator? What is the battery voltage at the positive terminal with the engine running and with the engine off.
I wouldn't trust the chain store battery and alternator testers.
Then, with the engine running, what is the voltage at the large terminal (red wire) on the alternator? What is the battery voltage at the positive terminal with the engine running and with the engine off.
I wouldn't trust the chain store battery and alternator testers.
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
Thanks for takeing your time
First, you need to charge the battery so that it will show something like 12.6v or more.
Then, with the engine running, what is the voltage at the large terminal (red wire) on the alternator? What is the battery voltage at the positive terminal with the engine running and with the engine off.
I wouldn't trust the chain store battery and alternator testers.
Then, with the engine running, what is the voltage at the large terminal (red wire) on the alternator? What is the battery voltage at the positive terminal with the engine running and with the engine off.
I wouldn't trust the chain store battery and alternator testers.
Pro
Joined: Oct 2012
Posts: 672
Likes: 2
From: Cheltenham, England
Sounds like the battery's shot, how old is it? have you tested/had it tested ? and I dont mean just putting a volt meter across it, if its the acid type get the gravity checked..take it to a battery shop and have it tested properly
Last edited by ricasso; Mar 11, 2013 at 01:39 PM.
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
just put in a new battery its not droping off like before but stays at 11.5 to 11.9 gitting better
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Is that reading from the analog voltmeter in the dash? A battery that shows 12v or less is either dying or is dead. At that voltage, a battery will not start the engine.
When you say you just put in a new battery, how log ago was that and what brand and group size is it?
Do you see the 11+ volt reading from a digital voltmeter? If so, there is a problem somewhere. It sounds like an internal wiring problem or a bad voltmeter gauge.
When you say you just put in a new battery, how log ago was that and what brand and group size is it?
Do you see the 11+ volt reading from a digital voltmeter? If so, there is a problem somewhere. It sounds like an internal wiring problem or a bad voltmeter gauge.
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Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 41
From: Baltimore, MD USA
One of the wires goes to the Battery Jumper Block. It's
located behind and below the battery. 8 fusible links are attached at that location. One of the fusible link wires goes to the Battery terminal of the Alternator.
You said you measure 14 volts at the Alternator and 11 volts
at the Battery. That would indicate something is wrong
with the wire that goes from the Alternator Battery terminal to the Positive terminal of the battery. Could be a poor connection at the Battery Jumper Block or a bad fusible link.
Melting Slicks
Joined: Apr 2011
Posts: 3,489
Likes: 473
From: New Jersey
Check that terminal block behind the battery! I had the same issue. I bought another alternator unnecessarily before I uncovered the real problem. The wires were loose and corroded. I ended up replacing the block as the post was broken loose of the Bakelite.
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
Is that reading from the analog voltmeter in the dash? A battery that shows 12v or less is either dying or is dead. At that voltage, a battery will not start the engine.
When you say you just put in a new battery, how log ago was that and what brand and group size is it?
Do you see the 11+ volt reading from a digital voltmeter? If so, there is a problem somewhere. It sounds like an internal wiring problem or a bad voltmeter gauge.
When you say you just put in a new battery, how log ago was that and what brand and group size is it?
Do you see the 11+ volt reading from a digital voltmeter? If so, there is a problem somewhere. It sounds like an internal wiring problem or a bad voltmeter gauge.
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
I thought it was terminal block too the nut was a little loose so I pulled and cleaned every thing before I bought a alternator . Thanks tor the diagram thats a big help
Last edited by 2fast4ujoe; Mar 14, 2013 at 01:30 PM. Reason: problem solved
Thread Starter
8th Gear
Joined: Mar 2013
Posts: 8
Likes: 0
Pro
Joined: Oct 2012
Posts: 672
Likes: 2
From: Cheltenham, England
