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Old 01-13-2005, 03:58 PM   #1
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Default Voltage drops

I just installed an optima red top battery thinking my old battery was bad. Still, with the new battery in, my voltage (according to the guage atleast) will drop down to the line above the red zone when the brakes are applied. when im on the gas though it is steady around 14 volts. Im the second owner of the car so im don't know for sure but im pretty sure the alternator (105 amp) isn't the one from the factory. I think it'* newer because it has a napa sticker on it with various information. Anyone have any idea what causes this? My only guess is that the wiring isn't quite cutting it anymore. Any help would be appreciated.
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Old 01-13-2005, 04:09 PM   #2
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GM alternators are well known for putting out just enough juice to keep the cars running. However, the only time I notice a drop anywhere close to what you described is when I'm stopped, on the brakes, and have the lights on and the heater cranked.

Not sure off the top of my head how to test and alternator, but that'* where I'd start.
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Old 01-13-2005, 04:11 PM   #3
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I also just noticed this:



my negative terminal to chassis ground is sharing a bolt with the ground for that round black object in the picture, can i put the negative terminal to chassis ground on it'* own bolt?

edit: I just went through and cleaned up the ground contact point with my dremel and wire brushed all the terminals and it'* still doing it.my alternator to battery positive wire looks like crap though and possibly even smaller than 8 guage. I'll probably have my dads friend look at it and if i get a new alt. definately am getting bigger wires.
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Old 01-13-2005, 04:39 PM   #4
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you can if you want

that round thing is your horn
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Old 01-13-2005, 04:53 PM   #5
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A. Where does that loose wire go?

B. What'* that green thingy?

If either of those are your ground wire, you may have found your problem
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Old 01-13-2005, 04:58 PM   #6
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that green thingy is taped to the ground wire from the horn and is attatched to a very small red wire.

that loose wire is my negative battery terminal to ground wire, it bolts on that bolt that the horn is grounded too, i took the picture after taking it off to sand the connection point. Everything is connected now.
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Old 01-13-2005, 05:08 PM   #7
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Its strange, my car does this too when there is a lot of stuff on (rear defrost, heater on high, headlights, etc.). Don't these alternators have a regulator on them? I've noticed that these cars really drop down low in terms of voltage when idleing. Strange....

Given all the posts with the same problem, it might not be a problem but just the way the car is designed.
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Old 01-13-2005, 05:18 PM   #8
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i have noticed that before but we're talking about it doing that with nothing on. no wipers, no rear defrost, heater turned to off, subs switched off at the remote lead, headunit off and headlights off as well.

with no accessories on at idle, it'* still a bit low but not bad




but then you hold down the brakes and.....

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Old 01-13-2005, 07:15 PM   #9
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Quote:
Originally Posted by 1994se


that is EXACTLY what my gague looks like at idle, I have said before I have tested the voltage right off the battery and it reads 14-14.4 all the time but the gague constantly reads lower than that, I dont trust my gague, I only use it for a reference
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Old 01-13-2005, 07:34 PM   #10
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My dads friend checked it out and said that the alternator is most likely fried. When i go and get a new one tomorrow can i get the one thats meant for the 94 SSEi? Don't they use a 125 amp alternator?
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