01Blackerado

iTrader: (4)

Whats it mean?? I have a ASP underdrive pulley so I went with a higher amp alt. I hooks up the same way that the stocker does but im not too sure on all the specifics!! At idle, my voltage meter is reading just above 9 but when I get to about 900 rpm it blasts above 14 volts. I dont know if it is sitting low because my underdrive pulley or what!? But this code has me a little conserned!! Thanks

thunder550

iTrader: (70)

https://www.performancetrucks.net/fo...d.php?t=368388


Alternator output is a compromise of idle output and high-RPM output. The larger you go and higher amperage you go, the higher peak output you can get, but the lower idle output you get. That is why most HO alts have small pulleys, to spin the alt faster to keep idle output higher. When you went to a 200 amp alternator, you actually probably lost output at idle, but gained it back above 1000 RPM. Your alt has a small pulley on it most likely, but that is designed around the stock crank pulley. Once you go to a smaller crank pulley, you spin the alt that much slower. If I were you I would put the stocker back on there and slap a smaller pulley on it. I doubt you'll be able to get much idle output from that HO alt with the underdrive pulley on there.

But to answer your question, the code you are getting is not related to the low idle voltage.

Quik

iTrader: (7)

dont worry about it. ive had it for awhile now every since i switched over to a LS1 102amp alternator

i dont have any voltage issues with efans,stereo and etc. i still wonder why some are going with such large alts. i did up grade to a larger charge wire which i do believe made the difference

Colby 04

The factory charge wire is a fuseable link on mine, is it not that way on the 6.0's or LS1's?

thunder550

iTrader: (70)

I am running 1/0 gauge charge wire with a 145 amp alt and my voltage still drops at idle when the lights are on and the a/c and e-fans kick on. Dual charging systems in the works