Crappy Alternator

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khan0165

Royal Smart Person
Jul 14, 2008
1,617
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Ontario, Canada
I am an Electrical Idiot, and I need some advice.

My car has several accessaries, and it struggles to keep up volts. I often have to chose between fans and headlights, and I can feel the engine lose spark when the fans come on.

I am running dual electric fans, not aftermarket, but I am not sure what vehicle they came from. They pull TONs of air, and so I assume they draw alot of amps. I also have a small sound system, with 6speakers, and my clock runs all the time. Asside from this, I occationally use my vent fans, and at night I do often have to use my highbeem lights.

My alternator is not original to the engine, and I believe it is off a late 80s, or early 90s Astro van. It tested at 78 amps capacity.

The repair guy says he can beef it up to 94amps in that casing size.

will this be enough?
I will try to get a voltmeter and see how much my entire system is drawing. But I wanted to see what you folks think...

should I have my alternator rebuilt to output 94amps? It will roughly cost me $80. Or are there beefier ones I can pull from a junkyard (there are not alot of junkyards around here) to run on my sbc350?
 

khan0165

Royal Smart Person
Jul 14, 2008
1,617
15
38
Ontario, Canada
I think I saw that thread a couple days ago, and didn't look at it... :blam:

thanks bud,
so according to this, I have a 12si... And talking to my friend who had his rebuilt, he says that my low rpm performance may actually get worse from going to 94 amps output.

And according to him, my 12si should be able to keep up with what I am running, and I should look for a problem instead... like a short?

I will see how much a new cs144 costs around here, and may go that route... This being Canada, I think they are almost $200.
 

khan0165

Royal Smart Person
Jul 14, 2008
1,617
15
38
Ontario, Canada
NOPE! I was wrong...
just called a place for a quote... $299
:puke:
 

monte olrac

G-Body Guru
Feb 11, 2009
926
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Wichita damn Falls Tx.
thats why I said junkyard, they are very well built so you probally can find a good one for 40 bucks or so, take it to a alt. shop and et it rebuilt if you want it like new, but they are expensive as hell new.
 

khan0165

Royal Smart Person
Jul 14, 2008
1,617
15
38
Ontario, Canada
yeah,

I'm gonna throw mine back in for now, cuz for the mean time I'm poor. And I'll call a few places around.
... But, I do happen to have a Lumina APV with some sort of a CS alternator. I don't think it's the 144, but it might be the 100amp one.

So, if the van dies, I'm stealing it, lol
 

axisg

Comic Book Super Hero
Jul 17, 2007
2,685
2,354
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Sounds like your battery can't keep up with the draw and/or your grounds need to be cleaned/changed. The most important ground is the heavy strap which runs from the alt bracket back to the battery. The stock alt should be able to keep up with what you listed. Take it to CTC and get a load test done and see how many Cold Cranking Amps it can hold.
 

khan0165

Royal Smart Person
Jul 14, 2008
1,617
15
38
Ontario, Canada
I've checked all my grounds, they're all good. I've been thru a couple of batteries now... I always choose one with good amp capacity, but the car keeps eating them.

I forgot to mention, I also have an alarm system... but I keep it off, to help cut down drain.

I disconnect the battery if I know the car will sit for more than a few days. If the car sits for over a week, it will drain the battery. I'm confused... the only thing that runs constantly in the car is the clock, and there's no way it has enough draw to kill the battery in a week???

I don't think the battery is an issue. It has plenty CCAs (I think 725 CCAs, and 650 CAs) and it doesn't struggle when cranking the engine... even if it's been sitting for a while. But there is definitly a drain in the electrical system, even when the car is off.

I had the alternator tested, and its capable of 78 amps (at high rpms). It is a 12si. It seems to hold volts well at high revs, but it struggles puttering around town at low revs... and it's twice as bad if I am using the fan and lights at the same time, it barely holds 12 volts.

what is CTC?
and how I do I get my car tested for current draw/drainage?

thanks,
 

Peter

Royal Smart Person
Jun 27, 2007
1,175
74
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MA
im no electrical genius but i would be willing to bet theres a short in the alternator
 

khan0165

Royal Smart Person
Jul 14, 2008
1,617
15
38
Ontario, Canada
redsx2434 said:
im no electrical genius but i would be willing to bet theres a short in the alternator
lol, if I was an electrical genius, I'd have this figured out... ha ha
can alternators short out?

I think there might be a short in my electrical system, but I have no clue how to trace it. And I can't afford to pay someone to trace it.
 
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