Voltage meter drops, especially at red lights. Replaced alternator twice with advanced auto parts remanufactured alternator. Same thing always. Starts out strong then slowly loses voltage, especially when cooling fans kick on. Upgraded all positive and negative wires from battery to 2 gauge. Little better but still fluctuates. Have heard these alternators from MEXICO suck. Could it just be the alternators, or is there maybe something else going on?

 

How low does it drop? Ever have a problem with the battery being dead after you drive it?As long as the voltage stays above 12 the battery is being charged. A voltage gauge will show a higher reading after starting the car because the alternator is recharging the battery.

 

You don't happen to be running a bbk under drive pulley are you? I did for a while on my '95 car and every time my rpm would fall below 2k voltage would drop off. Just a thought

 

have the same problem on my 98 TA replaced alt twice. charges fine until I turn on AC and the fans come on then at idle the volts drop off to 9 or 10 volts. Comes back up when driving?

 

I'd change brands. See if you can get a refund.

 

I am getting a refund on the remanufactured crap and they are giving me a brand new unit today. Hopefully this will solve the problem, if not then I really don't know what to do. It did drop into the yellow on the volts meter before I upgraded the wires to 2 gauge. Now it gets close to the yellow. I just bought a brand new Exide battery a couple months ago before I got the alternator. I will post what happens when i change later this afternoon. No underdrive pulleys that I can see.

 

Ok, now I'm started to get aggravated! Put in the BRAND NEW alternator and still the same thing. WTF?! I checked the gauges to make sure all the idiot lights work before I actually started the car and they do. I really don't think that the brand new is bad also. I will give calling the free tech hot line that came with the alternator a try and go from there. Anybody have any ideas out there? Sure could use some good advice right now.

 

I'd look for the problem elsewhere at this point. Check various connections for corrosion and maybe have your battery tested somewhere. Could be bad cables too.

 

Ya, gonna check voltages at different points of system and try to pinpoint the problem. Thanks for everyone's input. Will post what I find on Saturday. Gotta wait til then cause I don't have a meter, so I have to wait and borrow my nephews. Thanks again.

 

I would start with checking the engine ground to the chassis. Good luck.

 

Ok, just replaced braided ground wire from engine to chassis to 4 gauge one. Cleaned and used dielectric grease on contact points. Got a multimeter from Walmart for $27. Checked battery voltage, it was 13.7, checked voltage from alternator to battery, was about the same. Then checked the little wire that plugs into the back of the alternator for its voltage with just the key on, no engine running. I got 1.4 volts. The guy on the tech support told me yesterday it should be a minimum of 12 volts. What could be causing should such a low reading? I'm tired of this Florida heat and humidity, it's freakin brutal.

 

I just looked at a wiring diagram, and the little red wire that plugs into the Alt is for nothing more than the voltage gauge. 1.4 volts with the engine off shouldn't be a problem.

 

Wow! If that is true, and I am not saying that it's not, then the tech guy is an idiot. If you don't mind me asking, where did you get the wiring diagram? I would like to see it for myself. I have the service manuals for my car. They are the 2 book kind like they used at the dealerships, they can be a little bit of a pain in the butt to use. Thanks for sharing.

 

http://lt1swap.com/pictures/100_1786.jpg

lt1swap.com has a lot of wiring diagrams. The link above is for the specific page that says its only a feed wire to the gauge. Hope this helps.

 

Thanks for the link. That looks like the same book that I have, will look a little deeper and see what I can learn. I've been told that wire tells the alternator when to turn on. I just gotta take the time and really go thru that service manual. I plan on doing an engine pull in mid October, when the weather here in Florida cools off. It's just so hot and humid in the summer and frustration just seems to really magnify because of it. That's when I'll go thru the whole thing with a fine toothed comb and get things right. Hopefully, things will hold up til then and nothing gets fried. I'll keep a close eye on things and see how it goes. So for now, I'll say thanks to everybody and repost then.