4.7L Battery Light On, Burning Smell...

[Bahnstoermer]

I started the 4.7L in my 2008 4Runner, heard a whine, after a short drive the battery light came on. Blue Driver showed no codes. Drove it home, and have a burning smell / light smoke upon opening the hood...I couldn't investigate more at the moment, had to switch cars and go.

I'm at the very beginning of getting my bearings on possible issues...

Locked-up alternator? Common failures with these symptoms?

 

[ArthurKotb]

Sounds like the alternator pulley seized and your belt is burning because of it.

 

[AuSeeker]

I had my serpentine belt tensioner pulley bearing seize up on my V8 which squealed loudly and smell like burning rubber until the serpentine belt broke at which time the battery light came on, with many vehicles when the serpentine belt breaks it will also overheat because the belt also turns the water pump, but on these V8s the timing belt turns the water pump, so I could still drive until my battery died from not being charged, replaced the tensioner pulley bearing and installed a new serpentine belt and all was fine.

That being said you could have the same issue as I did if your serpentine belt is broken, or it could also be the serpentine belt idler pulley or both pulleys.

It could be as mentioned if the belt is still some what intact be the alternator seized up instead, but usually an alternator doesn't seize up they usually just quit working unless they have rusted inside.