battery drain

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battery drain

longsix
hey guys,
on my ,86 f150, 4.9l, the battery drains over a few days , when not in use.
i changed the altenator, checked voltage, engine running(12.3v).
recharged battery over night ,checked voltage(12.8v).
cranked truck, checked voltage(12.4).
new alt. has the plug built in, so i checked all connections, they seem ok.
what could i have overlooked?
thanks in adv....longsix
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Re: battery drain

Gary Lewis
Administrator
Your voltage should be 14.0 or more when running, so if it is 12.3 or 12.4 your alternator isn't working.

By "has the plug built in" do you mean it doesn't have a regulator on the fender?  If so it is the 2G alternator and you may have a wiring problem.  You might want to read this TSB from Ford on it and check your wiring: http://www.garysgaragemahal.com/96-21-04-2g-alternator-repair.html.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

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Re: battery drain

Steve83
Banned User
In reply to this post by longsix
Post several pics of the alt, its wiring, the battery terminals, the starter relay (on the inner fender), the body/frame/engine ground points...  Read this caption & follow the link for instructions on embedding pics in your posts: