Voltage issues

[shoobaah]

Hi all, had a couple quick questions.
I have a 95talon tsi awd, and i have some voltage fluctuation issues.
On my apexi neo,the voltage on the car fluctuates at an alarming rate between low13ish volts(while the car is running) to as high as 16.5ish volts(once again while car is running) All lights(including dash lights, headlights, interior lights) all fluctuate with the voltage readings. Every once in a while the car is idling the voltage will stay constant, and when that happens the lights act normal. It almost looks like the lights are "bouncing" to bass or something. (i do not have subs or anything) Sometimes my radio will randomly turn off whe the voltage dips too low, also.
Two weeks ago my alternator died, and i replaced that.
Two days ago i replaced my battery with an optima red top just to make sure the battery was fine.
When the car is not running, the battery stays constant(like it should) at around 12.8/12.7 volts, which i believe is normal.
Does anyone know what would cause the charging system to "overcharge" and fluctuate?
Also, i am assuming that too much voltage is taxing on the charging system, correct?

Thanks for all the help guys,
Dylan

 

[i_nick_2005_i]

Alternator for sure. The voltage regulator goes bad, which is in the alternator. Not safe to run it over-charging. It will fry things, such as that new battery you just bought.....

 

[RideJax94]

You said you replaced the alternator two weeks ago? Was it brand new or one with say a rebuilt core? Are all of your main grounds/grounds tight and secure? Always check your grounds for sure, even when replacing new electrical components. Even a little loose can make a big difference. What is the alternator itself putting out? Throw a meter on it and check the output. That will tell you right then and there whether your regulator is shot again. Also, make sure the belt is tight as well. A loose belt can cause voltage issues too. The throbbing of voltage is most likely what he said as well the regulator, so just throw a meter on there and check the output of the regulator while running obviously.

 

[Ahnubus_29]

Yeah it is the alternator these cars love to eat reman alternators like they are a fat kid eating cake. I finally bought an actual new oem alternator instead of a reman and have had no problems with my charging system since. I know that oem alternators a costly but well worth it since Im not having to change one every few months anynore.

 

[shoobaah]

yea i got it from autozone so its probably a reman.
Thing that bothers me is that it did this before and eventually the alternator shit the bed.
(the one that died two weeks ago)
When the car is running i disconnected the battery and it still ran a constant 12.7ish volts (no fluctuating) when the alternator is by itself, or the battery is by itself, it runs a constant, correct voltage. when you combine the two, its intermittent and inconsitent voltage.
Does that eliminate anything?

 

[kergilman]

The only thing that regulates that voltage is right there on that Alternator (unlike my 420a where the ECU regulates it so I had to replace the ECU when I started charging at 15 - 16 volts and blew the battery all over). Belt slippage you would hear at the same time you see a fluctuation.

 

[shoobaah]

hey ahnubus how much did that oem alternator run ya?
im assuming that because the voltage regulator is internal that you cant replace just that?

 

[i_nick_2005_i]

Just cost me $170, and that's after core......Regulators are over $100, so it's not really worth a rebuild IMO.

Edit: Nevermind, OEM's are $200+........If you go with AutoZone, as I did ^ you'll still have a lifetime warranty, for what it's worth.

 

[shoobaah]

yea i got mine at autozone two weeks ago and i have voltage issues still
hopefully i have my receipt laying around some where

 

[lengel]

This Is the exact same symptoms my car has. Did you resolve the problem?
Thanks Adam

 

[One Equals Two]

It could be a number of things, but here's what happened to me.

My ECU (DSMlink) was set improperly. Once I set it correctly, I was fine.

But, I've heard of ECUs frying and requiring a new one.

I'd also check wiring to make sure it's all clean and well grounded.

P.S. Red Tops are total garbage.. don't waste the money.