Okay guys, whenever i FIRST got my 4runner from the junkyard(was sold to the junkyard..and the junkyard was selling it) the ground wire coming from the battery to the body was burnt....

i replaced it and all has been well so far.


well i went out today after my truck has been sitting for 2 days and my batter is DEAD..has around 3.5V at the battery.

nothing works at all obviously, but whenever i jump start it everything works fine....and if i take off a cable..my truck stays running..so my alternator is working.


thing is, i think it might be OVER-charging possibly? i tested battery voltage across the battery posts while the 4runner was running and everything hooked up, and it read about 14-15V...which seems about normal...well when i tested voltage at the Alternator Post i got a hair over 16V.


So does this mean my alternator is bad and i can swap in a MR2 Alt?


if not, then i need some ideas on tracing down a parasitic draw......because my battery went from fully charged and truck running fine..to not even having enough voltage to turn ANY of my interior lights on...so OBVIOUSLY something is wrong.

 

i'm not sure if the burnt ground wire had anything to with it......but whenever i seen that i figured i'd have some electrical problems...



the 80amp Alternator fuse is fine, but instead of being copper colored it is burnt colored, i tested it and it tests out fine.

theres also a 30amp Fuse under the hood that is not in the main fuse box...it's in it's own little fuse box kinda beside the Diagnosis plug...idk what it is, but it looks corroded and such...but again tests out fine...it should be copper color just like the rest of them..but looks corroded like battery acid got on it or something..

 

cant bad diodes in an alternator drain the battery when its not running, works fine whenrunning but once its off the alt sucks it back down??

 

if you have a multi meter with an AMP reading. disconect the + when the truck is off. Place black wire on +post and red on + cable. It most likly read +4 amps or more.
Then remove the cable from the alt. Re test at battery. If it reads in the milli amps, you found your drain. Then replace your alt.

 

Have you at any time looked at the wire coming off the Alternator B terminal that goes up to the power distribution block.

I have seen these on the Alternator end get so burnt and brittle it is difficult for them to conduct .

I have also had bad ground cables cause the battery to drain down like what yours was.Upgraded grounds has solved quite a few problems

When you were testing the total load of all electrical goodies was powered up. I am sure you know that the battery should be fully charged when doing these tests.