Ok, here's a tuff one... I have a brand new battery and brand new alternator.
while running, my car stays around 10-11 volts and the battery light stays on... Any idea what this could be and why I'm not getting 13-14 volts while running like i should?

Bad Ground? If so.. what's the best way to check and locate it?

 

by "brand new" alternator, you mean "autozone reman"?

take a multimeter, test the voltage off the alty. one lead on the terminal for the cable to the battery, one on the case. if it's still crap, take it back, get another one (or just take it and get it tested).
if it's good, test off the alty case and the battery. still good, means ground problem. bad means that cable is bad.

 

What cables can I check if the battery and alt are both good?

 

primarily, check for corrosion on all of 'em. while you are examining them, make sure they aren't loose, or missing. not sure where all of the grounds, though.
Which engine do you have?

 

check for excessive resistance between the + side of the batt. and the charging side of the alt. (the big cable that comes off of it). This can either be done by doing an Ohm test or by checking for excessive voltage drop. If that is okay check for resistance between the - post and any ground on the vehicle. It could still be a bad alt. though so keep this in mind.

 

alt to battery - 11.32

alt to alt case - 11.43

battery - 11.43

all idiling at 800 rpm's What does this sound like?

 

Does the voltage increase with the rpms ? If so its probably the voltage regulator.

 

Agree, sounds like a bad regulator. Put a battery charger on it for 6-8Hrs and re-read, you should have >12.7V

 

Thanks guys... What's a voltage regulator? I've never heard of that... and where can I find it in the car? I'll just go ahead and change it out

 

it's an internal part of the alternator. if it's like most alternators, it would require a rebuild (disassembly and reassembly) to replace a bad volt reg.
and I haven't found a rebuild kit from a source I would trust, yet, so....

edit: to answer the first question, alternators put out power in alternating current (AC, the stuff you use in the house), and depending on speed, put out more volts (18v+, never bothered to test how high it can get). since a car requires 13v DC, you need a voltage regulator to up/down the voltage, and a diode tree (Rectifier bridge) to turn the AC into DC.

 

well i've had this problem for over a year that I just can't figure out... basically my car has a mind of its own. it's NA-T on mapecu2, I can crank it up, cold start and it will just randomly shut off on its own for no apparent reason. sometimes it idles for 20 min without shutting off... then when it does.. i cant start it again for another 15 min. When i try to get into boost, it sputters and jerks... then starts idling funny... Its defiantly an electrical issue.. I just can't figure it out. I've replaced everything. iacv, tps, battery, alt, all sensors on the block... still havent found a cure.

 

did you already replace the alternator or no? Low voltage on a battery that won't charge will pretty much affect everything on the car. All sensors, solenoids, etc. require voltage to work and with a weak electrical system, like you have now, will slow the entire car down. Get a new alternator first and then, if that doesn't fix it, start looking at other problems. Don't jump to anther problem without fixing the first, one step at a time...