What is my voltage supposed to be? I think I might have a bad alternator. HELP!!!

[-DSM2NR-]

My car has started acting really weird. If I drive it hard and hit max boost for around 4 seconds or so the rpms drop all the way and the car dies. Then, I have problems starting it back up again.

I think it might be the alternator that's causing the problem. The OEM alternator has been replaced with an autozone rebuilt one.

I hooked DSMlink up and it gave the the following voltage readings on the battery: With the car turned on and the headlights and wipers turned off it's reading about 12.38V and when I turn them on the Voltage drops to 11.87V.
The Voltage with the car turned off and the headlights and wipers on is about 12.27V.

Is this normal voltage or is there something seriously wrong with the alternator or battery.

Please help!!!

 

[tsi2nv]

well your voltage should be in the upper 13 to 14 range eather it is the alternator battery or there could be corrotion in the wires but that is only on much older cars... take it to pep boys and get a free charging test go from there

 

[Starscream]

Well, I had a similar situation happen to me last week. Turns out it was my alternator.

I'm pretty sure you have the same problem as me.

Have a look in my thread:

http://www.dsmtuners.com/forums/showthread.php?t=226014

A fully charged battery should be 12.6 volts. When cranking you could see voltage drops to almost 10 volts and the battery could still be good. The main thing is that the battery should jump back to at least 12.4-12.5 immediatly after cranking(without starting obviously).

If I were you I would have someone man the volt meter and with the car running and at a high idle turn on every accessory(rear defrost, lights, high beams, heater, etc..) and make sure the voltage doesnt drop. It might drop for a second but should be right back up to 13.5 or so volts once the alternator kicks in to compensate for the draw.

base voltage as stated about should be around 12.6.... if the battery is out of whack replace that first.. theres no point in diagnosing anything else with a krap battery..a no load test, (engine on, no accessories, 1500rpm) should be between 13-14.6v, and should never show more then 2 volts over base voltage... and a load test ( engine on, all accessories on, 2000 rpm) must read about .5 volts over the base voltage test... if not your alternator is not putting out enough juice to recharge the battery.. check it out and let us know

 

[-DSM2NR-]

thanks for the help. I'm sure it's the alternator. The battery was replaced with a brand new one a week ago so that shouldn't be the problem.

 

[Starscream]

Yeah, I'm pretty sure too it's the alternator. Get it to an auto electrical shop and have it tested either way.

Check out this page, this is where I'm getting my new alternator from...prices seem nice:

http://look.auto-parts-wholesale.com/parts/online_catalog/quote.jsp?year=1995&product=F4000-66625&application=000388650&part=Alternator&category=All&usemake=&returnurl=http://catalog.auto-parts-wholesale.com/basket.php?action=additem_framed&stylesheet=http://catalog.auto-parts-wholesale.com/stylesheet.php&phonenumber=1-888-267-1841&dp=true

 

[ChrisNelson]

I'm selling a really nice voltmeter gauge here: Http://nelsonautos.com/eclipse/eclipse.html

Install the gauge, and never have to guess again!