Kenner

hi all, i'm in a heep of trouble with my FC and can't seem to figure out what's wrong . anyways, here's what happened:

-first, i recharged my battery the night before from 10% to 100%.
-the next morning, i start my car and it starts just as it should.
-with a Schumacher charger, i tested the battery % and alternator % and it read 100% clear across the board.
-after warming it up for about 10 minutes, the volt meter gauge in the dashboard starts to decline a bit.
-subjected to a voltmeter with the engine still on, the battery falls from 14.7 volts to 11.9.
-i took a measurement of the alternator % with the Schumacher and it read 0.0% .
-the funny thing is, I tested the negative and positive currents from the alternator to the battery with a voltmeter and it showed normal numbers all around, showing no sign of blown fuses, faulty grounding, or the like.
-without a clue of what to do, I get in my car and give it a little gas, I rev to about 4000 rpm and voila, the volt gauge reads a healthy 14+ volts, haha, only to fall back down to 11.9-12 volts once I let it idle again.
-thinking I have a bad alternator, I stop the engine, run to Pep Boys and buy a remanufactured alternator made by Bosch. ...........What a waste...........
-after reinstalling the newly acquired alternator, I start the car, and it still reads 11.9-12 volts on the dashboard volt gauge.
-taking out my anger on the gas pedal I punch it a little, and what do you know, the volt gauge reads 13-14 volts, and it stays like this thoughout warmup.
-i go for a little drive and after driving about a block, , the volt gauge needle shoots up past the 15 mark and falls straight down to about 12-12.1 volts, only this time, no amount of gas or pedal punching could bring the voltage back up.
-to me, it looked like a voltage spike and apparently, something involved with it is murdering my alternators and killing the battery off.
-i go home, and recheck the battery. It reads 20%, down from 100% that same morning.........

please help, anyone got a clue?

HAILERS

So....if you rev the engine the alternator starts putting out, right? But at idle does not.

Your missing the excitation voltage at the small plug on the rear of the alternator. What is happening is that the alternator when spinning at a high speed is creating its own field voltage which is why you then see the 14 volts THEN but not at idle speeds.

Pull the small plug off the alternator. Turn the key to ON. See if you have voltage on the two small wires. If not, then replace the fuse. Free online fsm....online for free with schematics.

GTUser

Seeing any idiot lights? Checked your belt and its tension after installing new Alt?
Sounds like the alternator is still the problem if your grounds are clean and tight and your battery is good.
Check out the FSM:
http://www.teamfc3s.org/main/factory...cal_System.pdf

nitroracer

iTrader: (5)

also you gotta watch out for loose positive cables, thell also couse voltage spikes too. make sure the cable on the starter is tight, make sure the positive side of the battery is tight. i hope that helps you out.
Nick

AsianFlip06

ohh yeah just to let you know your battery might be just bad and that is causing it now to hold charge usually when u let it recharge from almost completly dead sometimes the plates inside get all hardened up and cant hold the charge during night. About the alternator connector in the back i doubt its that because i had it happen to me before all i had to do was rev it to 3.5k and it would stay at 14v even when i drop at idle.. all that connector does is tell the computer that u started the car up and that it needs to start charging now...check with the battery by getting it load tested....

HAILERS

For the alternator to put out, the field must have an excitation source. That is what one of the two wires in the back of the alternator do for a living. The other wire is a reference voltage for the regulator inside the alternator.

I'd suggest you find out if you have voltage on both of the small wires on the back of the alternator.

Kenner

thanks a bunch guys

also, i found a heavily frayed connection in the wiring from the alternator output node to the battery. the wire was holding on to the terminal at the end by only a couple strands. i broke it off by accident and plan to solder some extra wire and a new terminal. this may have likely caused the voltage spike, but i'm not sure. i'm gonna check the rest of the charging system.

i'm just wondering: is regular 12-gauge copper wire suitable for replacing the wire that connects from the alternator output to the battery?

about the connector behind the alternator, do you know where i could find a replacement, it's a little loose? eBay doesn't have any, at least I can't find any on there.