voltage drop over 5k rpm and lean out

[agt061794]

Hey guys just seeing what yalls input is on this.
Have a cammed 5.3 at WOT on a second to third pull at about 5500 rpm the voltage drops and my truck leans out to about 16-17.0 afr then when shifts into 3rd voltage comes back up and truck goes back to normal afr.
Im stuck between alternator or belt slipping what are some of yalls experiences,
Thanks Guys

[427 LS3]

What voltage is dropping? Your O2 sensors or your battery gauge? Not sure what other mods you have either, or what tuning you have done. Maybe some more info would help here.

[agt061794]

Well i have a 02 silverado ext cab short bed 4x4 with a 5.3 on 24s it?s got full bolt ons tsp bald eagle cam kit (titanium dual springs etc? Ls2 timing chain, comp lifters, melling high press oil pump, its studded, full 3 inch borla exhaust, vette servo, efans on Nelson harness. circle d 3200 converter, i just installed a fogger from nitrous Express have 150 pills in it. I have to install my walbro 255 fuel pump. And it is dyno tunes with hp tuners from Stickys dyno. Well anyway i noticed before i did anything with nitrous the truck would lean out in between shift on the afr it would lean to about 16-17% and i also noticed the lights would dim and altenator voltage would drop down to about 10v now the battery is about 6 months old i know it?s not that. So I?ve narrowed it down to an altenator or belt slipping. But the alt i have now is a 105 amp. So I?m gonna switch to a 145 amp. And see how it goes

[427 LS3]

I would do the same thing. Definitely sounds like an alternator issue. I would assume your injector PW would drop with lower voltage, hence the lean condition. Could be wrong though, but I'd start with the alternator too.

[agt061794]

yeah man it was the alternator i put the 145 amp in now i have no lean conditons on all motor or on spray worked perfect.