bII cant stay charged

truckguy · Oct 17, 2010

im finally getting around to having my 86 bii road ready. the battery is new and the alternator is ok too but after charging and starting and letting it run for awhile it wont start after i shut it off and i have to charge it again. i have no idea what to look for any help is appreciated. thanks

Nathan123 · Oct 17, 2010

I know it sounds stupid, but when you close the doors, do the cab lights go off? My tailgate would close and latch only halfway, kinda unnoticable, and leave both lights on. You really wont notice it unless your looking for it, or its dark out. What kind of battery is it? When my battery was bad, (I mean it was dead) my battery gauge needle vibrated back and forth. You could also load test the battery just to make sure its okay, new parts can always be bad.

4.0B2 · Oct 17, 2010

Put a test load on your battery. New does NOT mean good. Take it to AutoZone or somewhere and let then check both battery n alternator. And check for any drains.. If you have a gauge that can see how many amps are being pulled from your battery even when "nothing" is on.

truckguy · Oct 17, 2010

its a walmart battery. the lights turn off when i close the door. when i hook the charger to the batter its pulling about 5 amps.

Nathan123 · Oct 17, 2010

I had a walmart battery, came with the bronco when I bought it. It had the knock out stickers, it was one year old, Everstart MAXX. So not even two years later truck wont start, not even click, let alone turn over. Battery read 13.5 volts. Couldn't jump it with the charger, replaced the starter under warranty, nothin. Ended up being the battery (still had 6 months of the 3 year warranty!) The guy at walmart (10:00 on a wednesday now) swapped it out with no receipt cuz it had the sticker. The new one I got didnt have the knockout stickers, no date at all, you must save the receipt. My point is wal mart batteries are chitty.

Nathan123 · Oct 17, 2010

Oh yeah for the test, turn on the head lights and maybe the blower motor, and read the voltage, and your voltage should correspond with this table. If you dont have amperage, you dont have start.

swamprat · Oct 17, 2010

You got a power drain some where. Probably a short some where.

truckguy · Oct 17, 2010

thats what my stepdad told me he thinks its a short. is there an easy way to finding it or am i gonna have to take it to a mechanic

Earl43P · Oct 17, 2010

Got a voltmeter? Many "alternator" problems are a bad cable.
What is the voltage at the red battery terminal with the engine running? Should be at least 13.5v.

Do the same voltage test at the large alternator post and the solenoid. Check your grounds.

http://www.therangerstation.com/tech_library/chargingsystem.htm
http://www.misterfixit.com/baddiode.htm
http://www.therangerstation.com/tech_library/chargetroubleshooting.htm

http://www.therangerstation.com/tech_library/EDiagrams/files/diagram_charging_1983to1985_1.JPG

swamprat · Oct 17, 2010

volt meter and wire diagram. check to see what has power when it shouldnt. check your grounds. Also look for crimped wires or corroded wire or connections.

adsm08 · Oct 17, 2010

Ok, you don't have a "short". Short circuits blow fuses. Parasitic draws kill batteries over night. You either have no charging, or a parasitic draw.

Make sure you are getting a charge, at least 13.5V and not more than 14.5V as read across the battery terminals with the engine at idle.

If that checks out hook an amp meter to the positive cable and then unhook the cable from the battery (I know, a bit of a trick) if it reads more than .002 amps, start pulling fuses until the number drops off to .002 or less.

truckguy · Oct 24, 2010

i think i fixed the problem. my starter relay was getting power all the time so i replaced it with a new one and it started a whole lot better and now is not draining the battery.

bII cant stay charged

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