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Discussion Starter · #1 ·
i just replaced the altenator on my 91 Sentra E a few months ago (about 10k miles ago) and since then, the condition of the car has dropped, which has me not caring for the car as much. but anyway, just yesterday, i got a dead battery, and me and two friends could not get it push started for our lives (hell we towed it with another car to get it moving) but i got jumper cables, and it started right up, i then drove it 10 miles home from work, which is 95% highway driving at 70mph. i didnt have any problems till i was off the high way, and the engine wasnt revving (redlights, etc) well with the car home, i decided its time for a new battery, cuz the old one was starting to leak at the top, and had some NASTY yellow/lime green sludge at the bottom (from sitting on the battery tray) now that the battery has been "broken in" im still having the same problem of: when the idle RPMS drop (i have an erratic idle) the door/seatbelt/lights are on buzzer buzzes once, then turns off once the idle is correct, and the BRAKE light flickers, but i have yet to see the battery light come on. which is another problem, when you start the car and all the idiot lights check themselves, sahouldnt the battery light come up to? i havent seen the battery light up since the last altenator died, and when i had the dead battery, that light was nowhere to be seen.


does this sound like an altenator, or just a reallllllly bad electrical problem (cuz when i drive through big puddles in the rain the buzzer will start going crazy :eek: in addition the entire bottom half of the alt is covered in oil :(. this is more of a rant, but id like to know if it sounds like the altenator or something else.
 

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yeah.... when you start your car and all those little warning lights come on.. your charge indicator (battery) light MUST come on. it comes on if there's a complete circuit through the regulator, brushes, and armature coil, which there should be. that means the field is energized and producing the electromagnetic current you need. if that light doesn't come on during the bulb check, there's either an internal fault inside the alternator, like a bad regulator, or that 2-prong connector on the alternator is loose. but to make a long story short... when you start your engine, if your charge indicator doesn't come on with the oil pressure light and CEL and everything, 9 times outta 10 it's an alternator issue.

but anyway, get a screwdriver and a digital voltmeter. connect the voltmeter to the battery terminals. you should read about 12 to 12.6 volts. now start the engine and note the reading. it should be at least 13.8, but no higher than like 14.6. if it's still around 12ish, rev the engine past 3000 a few times. sometimes that can kick an alternator on if there's a field problem. now shut the engine off, and turn the ignition back on. touch a screwdriver to the rear center of the alternator. you should feel a slight magnetic pull.

it's also very possible the bulb can be burned out too. if the bulb is burned out, the alternator won't charge. the current to the alternator's field actually flows through that bulb's filament like a fuse. if that filament breaks, the field won't get energized, meaning there's no electromagnetism being created, meaning no current will be produced. sometimes the alternator will self-energize and kick itself on if you raise the RPMs past 3000. a way to check this is to disconnect that 2-wire harness at the alternator. turn the ignition key ON (warning lights should come on, but don't start the engine.) get a short piece of wire. on that connector, there is one thick wire (white)and one thin wire (yellow w/ red stripe). stick one end of your test lead into the prong for the thin yellow wire, and touch the other end to a grounded surface like the engine block or negative battery terminal. your charge indicator light should now be on. if not, check the bulb.

also, when you're driving, don't count on the charge indicator to warn you of a problem. most alternator problems won't cause that light to come on.

and since I've read about 8 or 9 posts already about this, there's a reason your brake warning light comes on if you have a bad alternator. this is the result of a little critter under the dash called the bulb check relay. its sole purpose is to turn on the brake warning light whenever the charge indicator light comes on. nissan does that intentionally so that when you turn the key, the brake light comes on for the bulb check with the rest of the red lights. I've read posts wondering why they're in exact synchronization, and that's why. but apparently nissan didn't figure out that if there's an alternator problem, both warning lights would come on instead of just the one with the battery on it. toyota and mazda do this too.
 

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my 94 sentra goes through alternators every few months. they don't die completely, but if I'm driving with the headlights, defogger, and stuff on, the output starts to suck. I think this is cos of my oil leak. the belt sprays oil into the alternator and ruins the connections inside. god bless the lifetime warranty.

anyway, I hope my above post can help you a little bit. if you have any more questions, feel free to ask.

Dan
 

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Discussion Starter · #4 ·
blackmaxima88 said:
my 94 sentra goes through alternators every few months. they don't die completely, but if I'm driving with the headlights, defogger, and stuff on, the output starts to suck. I think this is cos of my oil leak. the belt sprays oil into the alternator and ruins the connections inside. god bless the lifetime warranty.

anyway, I hope my above post can help you a little bit. if you have any more questions, feel free to ask.

Dan
wow, just wow!!!!!! you explained everything i need to know. thank you!!!!! im gonna try everything you said tomorrow....that is if the car will make it to work and back one more time. and yea,if it is the alternator, i think the front main seal is what killed it, there is oil EVERYWHERE.
 

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yeah I think that's what's killing my alternators. I went to take off the alternator belt last night and oil was literally dripping from inside the alternator. I was losing about 1 to 1.5 quarts a week and it was leaking on the belts. I'm in the process of replacing the seal now -- like literally, I just came upstairs to see if anyone replied to my other post. once everything's dry, I'm returning the alternator under warranty and puttin a new one in there. I hope that makes a difference.

Dan
 
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