when truck is running and you stop the voltage drops down very low. start up again and it picks up again to normal. when you first start it, it's ok but when it warms up it drops when you stop. i have replaced cables, cleaned ground, tested voltage at battery ok when you speed it up.what else should i check? the alternator looks new, i think it's beck arnely or something like that. otherwise the truck runs fine.
1994 f150 5.0 charging problem
Jul 25, 2006
5 Replies
Get a multi meter and find out how low is low.
I don't know how low it is dropped, but both ford trucks i had did this... now we're talking a drop of 2 volts maybe, 3 tops.
stalled just once, when i pull the trailer at nite it seems worse.
Without a voltmeter, it's just a guess. Normal system voltage is pretty "tight", in the 13.5 to 14.5 volt range, depending on heat and state of battery charge. It sound like your warm idle is too low, causing the alternator to not be charging at low rpm.
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