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charging

cscarlson

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2003 50Th Corvette
when i use my a/c the battery seems not want to charge, i have noticed that with the a/c going the alternator vibrates, the battery is new and the battery charges fine if i don't use the a/c. any thoughts?
 
S

sac001

Guest
Carl,

First, stick to the basics. Check the tension on the Alt belt. The load on the system with the AC running may cause a somewhat loose ALT belt to not work properly.

Also, check your connections at the ALT, and your battery cables and grounds everywhere.

Steve :w
 

cscarlson

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belt is tight to alternator. checked the connections to battery and they seem fine?
 
C

c4ever

Guest
CS,
I would run a check on the Alt. Some suppliers like Autozone will perform the test at no cost. I have noticed on my 85 that the A/C does draw quite a bit. At idle with A/C on my voltage reads only 11.6 and 13.9 at cruisin. Quite a difference. In the 82 it dips to about 12.7-13 at idle with A/C running at Max.
I get a lot of belt slap on the 82 with A/C running. It seems to be a common problem but I gotta believe it wasn't engineered this way.

Carlo
 

cscarlson

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does you battery charge properly when your not running the a/c. did you replace your alternator because of this?
 

vigman

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Remember

the Vette alt is slightly under rated.

I do get a drop when running the AC full blast
( Compressor, main fan and AUX if fitted & Blower Fan )

So it's a bit of a load... I do not have alot of belt jiggle however.

About 12.4 volts when mines @ Idle.
I have a WORKED AC delco reman.

Vig!
 

cscarlson

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I do not have any belt jiggle. my alternator vibrates .
 
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none right now :(
I think your alternator is just about dead. Get to a discount auto store to test it.... if it is bad, then get one with a lifetime warrantee from them... they are usually pretty cheap, and since the bearings on the early C4 alternators were too small, they break all the time. The good news is it is really easy to fix
 

vigman

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DO NOT GET A CHEAP ONE!!!!!!

The Pep Boys Alt's are NOT worth the time to throw em in.....

The NEW insulator they install is underated for TEMP... the positive output stud gets HOT & Melts the insulator causing a SHORT to ground!


BAD STUFF!


Vig!
 

cscarlson

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what makes you think it's the alternator going bad?
 

vigman

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CS???!

Is this for your 80??

Or is this a C-4 car.....

Are you basing your charge/ lack of charge on the AMP meter in the dash?

What's the real deal... confused??!!

Vig!
 

cscarlson

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this is my 80 vette. i am basing it on starting or lack of trying to start after i use the a/c and turn the engine off. and the amp
meter reading.
 

vigman

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In review

When you use the AC and you drive for a while... you shut down and the car will

a) Not crank at all?

b) SLOWLY crank but not enough to fire?


AND

Do you just wait "X" amount of time and it fires right up... or you have to get a jump?



Vig!
 

cscarlson

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A AND B...

AND SOMETIMES HAVE TO JUMP IT
 
S

Shadowing1985v

Guest
hmm,

thats kinda wierd, cuase,

if it works some times,, after you jump it then that means your alt is still putting out some kind of juice

and it must be hiting your battery,, so that means your fuse links are good.


it sounds like your battery is out, cuase you say some times u have to jump it and other times you don't, your battery could be shorting out your alt, to make it read wrong,,

a bad battery can make a alt go bad
if this is on your 80's model,, i woudln't know, i own a c4 and the way ti works is,, it goes from your alt to your starter to your battery,, thats how the L98's are


but it also sounds like your alt is going out,, so anyways,, here is how u can tell you need a ohm meter

touch the positive and negitive on your bat when the car is off, "for voltage", it sould read like 12 volts , close to 12 volts,,if it dones't then your bat is dead, or is bad

then turn your car on, and do it again it should read like 14 to 15 volts some where around there, if it doesn't read that then your alt is broken


but then again i don't know how 80's are wired, but no matter how they are wired the test i just told you will work, no mater, what,, i am just saying maybe its a fuse link, only way to know is to put it on a lift and look for it,, sigh,, , do this test, and it will tell you whats wrong
 
S

sac001

Guest
Carl, you can also go to a local Battrery Warehouse (if you have one) and they can "load Test" the battery. What they do is put a meter on the battery to check voltage, then put an electrical load on it to see if it will handle it or if the cells in the battery are bad.

They will also check the output of the Alternator (as explained in the previous post). You start by measuring voltage (across the two battery terminals) with the car off. Then check again with the car running. I've not seen much above 14 volts with most cars, but take the measurement anyway. Then just for kicks, throw on the AC and see what you get there.

Somewhere in these numbers you should get a good clue as to what is going on.

While you're at it, check the battery connection to the positive terminal block in the battery compartment. You might want to take everything apart, clean it up with a wire brush, put some of the electrical lube on it and put it back together as well.

Let us know what you get with the voltmeter.

Steve :w
 

vigman

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Then

Do you have a voltmeter handy?

The NEXT time it does this I would suggest having a cigarette lighter adaptor that hooks up to a volt meter so you can ACTUALLY measure the REAL voltage on the batt.

I'm guessing one of two things.....

You state the battery's new.....
So IF it's not getting a proper charge then problem solved... bad alt

And your voltage will be under 12 volts....

Side bar....
( It would be of interest to me to see if there is an AC component on the DC buss... like a diode blown... about 5 volts AC would indicate a diode is failing)

And you are only geting charge on 2 of the 3 phases of the Alt.

OR

If the car won't start...then say 30 minutes or more...later it spins right up then it could be heat soak on the starter.... the hotter the starter.. the MORE current it will take to spin it.


An other test


turn your headlights on

then crank

If it dims down really FAR... then the batt cannot deliver enough current.


Vig!
 

cscarlson

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2003 50Th Corvette
I will check this tonight and let you know. oh...i did notice yesterdaY that whan i stopped at a light the car was rough feeeling, could this be the alternator?
 

vigman

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88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Depends

If the voltage was low enough that the spark can barely fire then maybe....... with out an accurate test... hard to say.


Vig!
 

cscarlson

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I will have the alternator tested tonight and look at the other things an let you know what's happening.
 

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