Low Voltage issue?

[HokieDSM]

I've been keeping an eye on my voltage lately using my logger, and while I'm idling and driving without using any accessories (no lights, stereo off, etc) - I get about 13.93v - but - especially at night with my lights on - it drops as low as 12.1-12.3v. Is this kind of drop normal? I notice that my lights (interior/dash & exterior) tend to dim at idle, while they perk back up when I get back on the gas.

Some people say this is normal - but I hadn't noticed it until just a couple of months ago, and I know that my 1G n/t and my 2G never did this.

Any clue what's causing it?

 

[Korndogg]

i'd say time for a nice, shiny new alternator

edit:
btw.. voltage should be ~12V with the car not running, and ~14-14.5 with it running... (if the alternator is functioning properly)

 

[HokieDSM]

See - that's the thing. I replaced my alternator in December.

The dimming started about six weeks after I got the alternator done.

 

[BUCK]

Make sure you have no Power Steering Fluid leaks on your Alt - that will kill the Voltage Regulator in a Hearbeat & can toast your ECU...

I had my Bumper to Bumper guy look up the Highest Amp Mitsu Alternator that would fit a 1G:

- Max amperage 121 amps

- 100 amps at 3000rpm

- Max 1548 watts

- Manufacturer Ampere - Ampere P/N 21491

- Cost was about $150.00 - I run a 1 Farad Cap too with an El-Cheapo Battery. I put it on Car Ramps & come from underneath - It's still a PITA...

 

[DevilSperm]

Originally posted by BUCK
Make sure you have no Power Steering Fluid leaks on your Alt - that will kill the Voltage Regulator in a Hearbeat & can toast your ECU...

SHIT, i got PS fluid all over hell...now im scared

 

[HokieDSM]

PS looks fine -

When I had the alternator done, it was kind of done in a rush, and I really didn't have the time to specify what type of alt to put in - I do know that is' remanifacturered though. I had asked the mechanic (normally I would have done it myself, but it was out of my hands) to put in the highest amp they could - but I really don't know what went in there.

How can I test the capacity of the alternator?