Voltage drop after changing cooling fan settings

[taguru]

Anyone ever run into this? I dropped the cooling fan settings, first stage 190/195, second stage 200/205. I live in Florida so the fans run alot as it is but I noticed recently that after the motor warms up and the fans start kicking on that the voltage drops from 14.5 to around 13 and sometimes when it is really hot it'll drop down to 12- 12.5.

2001 Trans Am, LS1, cam, heads, etc...

[gofastwclass]

There is a place in many calibrations called Cooling Fan Airflow (or something similar) to adjust for airflow requirements when the fans are on. That setting really helps keep the engine running with the increased load of the fans on the electrical system. However if you're using stock fans with a stock (base) calibration I think it should be close but it's something to try and see. If that doesn't work, it sounds like you could have a wiring / charging issue or bad fan(s).

[taguru]

Problem only started after I changed the fan settings.

[taguru]

Should I be adjusting AC pressure, delay, minimum time, etc...??

[matty b]

Load test the charging system with a VAT machine, not one of the little hand held charging system testers that they have at the autparts store. I have a feeling your alternator is going bad and the small differences in idle speed vs temp are dropping it below its abilities. You aren't running an underdrive pulley are you?

[taguru]

Yeah that would make sense. Maybe it took the added load of the fans staying on longer to reveal itself.

I was just thinking that since the voltage only started dropping since I made the temperature change that it must be directly related and maybe there was something that I didn't know about the other fan settings that I was supposed to change when I changed the temperature settings.

I'll start looking into that.