Voltage drop while driving

[DragRacer404]

What would cause my voltage to drop while I am driving? It dropped down to 10.9. Once I stop it will raise back up to 13.1. I'm not sure if it will go lower than 10.9 or not but I don't really want to find out. Any idea what causes this? Alt and battery is brand new.

 

[erald01]

It could be a few things, check and see if the belt on the alternator is not sliping, and make sure the wire going from the alternator to the battery is good. I had that problem with my KIA, and i just got done changing it.

 

[DragRacer404]

It probably is slipping. I'll check it out this weekend.. thanks for the input on the common sense i missed out on haha

 

[Bewst93TSi]

Is it making noise? you can usually hear a slipping belt!

 

[-LA-]

When you say driving? Are you stopped, and idle, or moving? or does it matter? Does it drop when you are doing both?

Do you have any high power stereo equipment running, also? Check and also see if it drops up and down a lot when say like your blinker is blinking, turn head lights on, and/or press the brakes.

Probably the belt, as others have suggested. Just because alternator is new, really don't mean it's good. Sounds like the voltage regulator is bad. Free to have it checked along with your battery.

 

[DragRacer404]

Usually when I get on it a few times it will start to drop, but when I come to a red light it will charge back up. I haven't seen a problem when just driving normal. So I am thinking its a slipping belt at higher RPMs. I cannot hear the belt squealing, but I couldn't hear my belt slipping on my 03 mach 1 with the EATON s/c either.

If I am idling and I turn my head lights on, my meter will drop .1 voltage but it will come right back up. I'll have to check everything during the weekend when I have day light... only drive the car maybe 5 miles a month so far, so not much mileage to really see if it will drop voltage much. I know I drove it home about 45 miles when I bought it and it did not drop AT ALL when driving normally.

 

[Defiant]

Your "new" [rebuilt] alternator has shit the bed.

 

[2GeNTSi]

Could a bad regulator cause the headlights to burn out? My headlights recently went out (after a few days of noticing a dim hi-beam indicator on the instrument panel). I found it odd as well that my hi-beams were running with just my low-beams switched on before it went out.

Just yesterday I brought my car home and noticed on my TT that when I tried to turn on the headlights, the voltage dropped from 14 to 10.5-11v. I also notice my fuel pump is louder as well (I might just be thinking it is louder).

I haven't had a chance to work on it yet, but I've been trying to do as much research as possible before I dive into it.