my 82 yota had a weak starter,started fine when cold,but once warm.....like i had a dead battery.
swaped the starter,battery showing 12.90,load tested good,while running the battery is showing 13.80,undo the battery,alt is pushing 14.70 volts.
but the gauge in the cab is showing 8-9 volts and jumps.
whats going on....is this common?

 

maybe gauge is screwed

 

sounds like a bad gauge or bad connections somewhere.

 

guess ill start tracing wires.....anyone know where the meter gets its feed from.
ill start digging real soon.

 

ok update time.
since my last post,ive changed the battery,every 2 days she was dead.
yesterday i noticed in idle the meter will read 12 volts,steady climbing and reaching 14 volts,on acceleration the volts drop down to 8-9 volts.
after 2 days,dead battery again.

alternator puts out 14 in idle,my battery load test good when charged up.

should i look into the alternator or the voltage regulator?
im swapping the engine at the moment,just dont want the same problems after the swap.
i drive 60 miles a day to work,i cant afford to be late.....what do you guys think ?
i believe the gauge is fine.

something else.
with everything off,when i hook up the battery...im getting faint sparks....as if a light was on.
but nothing is on....is this normal....or should i go through the wiring while the engine is out?

 

update....with problems.

ive swaped the engine,changed the alternator,the v regulator,the short harness connecting the alt to the main harness,the original harness has a bad conector.
ive checked the fusebox,checked connections....still no charging from the alt or regulator.
New alternator and reg, still no volts.
I got hot supplied to alt and regulator.
Guess its wire time.

im getting really aggrevated,quickly.
is there a know fuseable ling in the charging circuit?

my alt is putting out 0.75 volts,the white hot is sending 12 to the alt,the harness for the reg is 5 wires,4 wires show 12 volts going into the reg.....still no charge.
wtf?
is there a fuse or reklay somewhere that im missing?

ive been through my haynes manual,tried fsm,but nothing yet on the 82's charging system/wiring diagram.

 

The excitation power for the alternator comes from the ENGINE fuse (RED wire) and it goes to The IG terminal on the IC voltage regulator or the Tirill voltage regulator. White wire is the output wire to the battery and the Yellow wire goes to the charge light relay. The fusible links are at the Positive (+) battery terminal.

 

thanx for that insight,ill dig into it tomorrow night after work.
im scratching my head on this one.
if you think of anymore wiring on the charging system....please post up.

question....if the charge light in the dash isnt working will this interupt the charging system?
question....i pulled the engine fuse from the box....she still fires right up and drives....is this normal?

 

nothing changed,just put in another new voltage reg...still no fire.
i tried grounding the alt,putting hot dirrectly to the 2 poles on the alt....still nothing.gonna pull the aly in a few mins and get it tested.it was new in febuary.
gonna have to find wiring diagrams to locate the ig wire on the regulator.

 

Ignition power supply wire is the Red wire in the harness that plugs into the Voltage regulator.

 

yes im getting 12volts to all 5 wires on the harness that plugs into the regulator.
im leaning towards the alternator,even with reg unplugged,still no power from alt...just battery power going in...nothing more comming out at any rpm.
gonna exchange the $30 alt tomorrow....if it still dont work...gm single wire.
can you guys suggest a certim model gm.my auto zone cant find it unless i tell them vehicle info the alt came off of.

i read somewhere a 94 s10 had a 100 amp single wire...but thats a $120 alt.
somewhere there is a $50 gm single...80 amp i think.