Charging system woes

[morganson]

So when i bought my supra (88 turbo auto) i supposedly had a 140a alternator on it. Charging stayed at around 14v but never though a whole lot about it. Well it craped out on me sat night and of course i broke the stud while taking the wire off. So i sourced another unit Advance auto part number 14995 from a 92 turbo. I put it on and this thing is idling around 11.2 to 11.9 but when you idle up it lvls out at 12.6 around 2500 rpms and up from there. My question is shouldn't this idle around 12.6 and go up from there when necessary? And what other systems interact with the alt system. Both fuses are brand new for good measure but no change in voltage.

 

[hvyman]

Should be at 13.5 - 14v. Take it back and get another.

 

[Dirgle]

Hvyman is probably right, however check your fuses. There are three for the alternator, and can cause the alternator not to fully energize.

Engine Bay:
FL ALT 100A

Driverside Kick Panel:
10A ENG Fuse
7.5A IGN Fuse

Never hurts to take a look at these before you go back to the parts store.

 

[mirage83]

+1, what Hvy said. At just over 12v it isn't putting out enough to keep the battery charged as well as running the car and anything like headlights, radio's, wipers, etc.

It's not unknown at all to get a faulty unit from Autozone. My FiL once went through 6 defective starters before getting one that actually worked properly. Just be glad the alternator is so comparatively easy to swap out. That's definitely not the case with all parts and vehicles.

 

[morganson]

Indeed. I didn't know about the ones in the kick panel. I will double check that.