Low Voltage Issue

[94svtturbo]

So about a month ago my car started having low voltage problems. it runs just fine. but the voltage is at like 12.5 volts at idle and its stays there throughout the RPM range. I have a digital readout of the voltage on my turbo timer so i know exactly what it is. It fluctuates a little from 12.5 to13.0 then it will dip just barely into the 11 volt range for a bit. I have taken the battery and alternator off of the car and had them tested and they test perfect. they are relatively new.

And Its nothing i changed cuz it was fine then one day it just started acting up

Anyone got any ideas of what could be causing this?

 

[CC'S95GT]

sounds like the alt to me. It should be putting out @ 14.5 vdc.
maybe the test needs to be ran longer to allow time for the alt to warm up.

 

[94svtturbo]

I pulled it off the car at normal operating temp then drove directly to the auto parts store and tested it myself on the machine. put out 14 volts of the bench tester. but somewhere in my car that number drops

 

[ttocs]

I have noticed my temps will drop the voltage a little bit in summer, and actually gain a bit in the winter. I was concerned because this winter I was getting close to 15v sometimes but it is back down to a little lower then I would like it to be now.

your not running underdrive pullies are you?

If you want to give your electrical system a quick cleaning, remove the battery connections and grounds and clean them, if yer feeling real crazy upgrade the stock grounds/power wires as they are weak as hell anyway.

 

[94svtturbo]

nope i am not running any underdrive pullies. All factory pullies. the AC and smog pump have been delted a long time ago

 

[CC'S95GT]

have you ohm'd out the battery and charging cables. ck'd all connections to be clean and tight.
I have seen corrosion get inside the insulation on the battery cables and look fine on the outside.

 

[94svtturbo]

have you ohm'd out the battery and charging cables. ck'd all connections to be clean and tight.
I have seen corrosion get inside the insulation on the battery cables and look fine on the outside.

No i have not. I have never heard of "ohm'ing" something. how would i go about it. Also can anyone tell me what the normal voltage for an SN95 5.0 car? with lights on even

 

[CC'S95GT]

ohm's is the measure of resistance to current flow.
You'll need to disconnect both ends of the cable to do the ck. correctly
most alternators can maintain voltage at 14.5vdc. +/- .5. With all accessories on.

 

[94svtturbo]

Ok. I'll try to check that today or tmrw

 

[94svtturbo]

What should the Ohm resistance read through that wire?

 

[CC'S95GT]

should be zero or very near that. like when you touch the pos and neg lead together