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Charging


bancline's Avatar
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07-26-03, 07:32 AM   #1  
bancline
91 Vette - Charging

I have a 91 Corvette. The motor wants to quit running when stopped and the charge indicator shows it is not charging. When driving or in neutral with the engine accelerated, the indicator shows it is charging. I charged the battery overnight and it starts the motor fine, but seems to gradually discharge. The motor will die if left to idle. The battery is about one year old. Does this sound like battery,regulator or alternator?


Last edited by bancline; 07-26-03 at 08:08 AM.
 
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07-26-03, 08:14 AM   #2  
Possibly a 2 part problem..First the idle issue, and then the alternator..I'd take care of the idle issue first. Have you had a good tune up done lately? (plugs, wires, timing, set base idle) Once this is done, it may take care of the charging problem, but I'd get the alternator checked anyway,after . The regulator is internal to the alternator. If the engine isn't turning fast enough to create a good output, you'll slowly but surely drain the battery, but it's possible to have a weak regulator..

 
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07-26-03, 08:57 AM   #3  
Check the battery voltage while running. It should be 13 plus volts.
If not, I suspect the alternator.

fred

 
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07-26-03, 10:46 AM   #4  
bancline
Thanks for the input. It seems to be charging at the correct level when driving, but then drops to no charge when I stop at a light. Eventually, the motor will start trying to go dead unless I can accelerate the motor. What do you think?

 
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07-26-03, 12:06 PM   #5  
"seems to be charging" won't cut it.

PUT A METER ON IT!!
fred

 
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07-26-03, 06:49 PM   #6  
As I said earlier..Take care of the idling problem and most likely the charging problem will take care of itself..The alternator's output is directly dependant upon the revolutions of the engine..(to a point..the regulator keeps it from over charging)..So, low rpm's=low alternator output....

My cents...

 
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07-26-03, 08:02 PM   #7  
As info:
My Z71 alternator went bad about two months ago.
When I slowed down to idle at a light it almost stalled every time.
It could be either.
fred

 
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07-26-03, 10:53 PM   #8  
Measure the output!

Once again: measure the voltage at the battery when the engine is above 1500 rpm. Most alternators don't turn on until 1200 rpm is reached. The voltage at the battery should be around 14.6 volts (max).

Tony

 
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07-27-03, 12:42 AM   #9  
On this computerized vehicle, the idle problem is very likely directly related to the charging problem. If the system is running on 10 volts, it will begin to die. Once the charge in the battery gets low enough, it WILL kill the engine unless you rev it up.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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07-27-03, 06:05 AM   #10  
bancline
Thanks for the input again....I charged the battery back up last night. Before doing so, I pulled the caps (even tho a maintenance free) and found a couple cells low. Refilled those. (Hopefully tap water is ok) Just took it out for a spin and it is charging and running like no problem. I will try it this week and let you know the results.

 
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07-27-03, 07:59 AM   #11  
Joe_F
This is a 1991 Corvette, not a 1972 Pinto. Fix it right!

The battery is shot, throw it out for a new Delco unit, that's #1.

As noted, you probably have a bad alternator. A $35 digital meter from Sears or any electronics store will help confirm that. Get an AC Delco replacement from the parts store.

As noted by MSA, a good tuneup can never hurt.

 
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07-27-03, 10:07 AM   #12  
If the cells were low on a mantainence free battery that should tell you something.The battery is cooked.Have the charging system tested after replacement.

 
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07-29-03, 04:58 PM   #13  
bancline
Thanks to all the input. Here is the answer.....Took it to a diagnostic center today....Results...Bad Battery !!!!!
Timing, Alt, etc. all good...

 
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07-29-03, 10:29 PM   #14  
Hello!

Glad you got it straightened out!

Tony

 
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