1996 f-250 7.3 diesel help

ok got 1996 f-250 7.3 diesel
2 new batts changed the alt to a new one
the problem is it take over a min for it to start to charge and put out anything
even if i rev the truck .
then it starts to read on the gage and charging 14v after a min or so

so what can it be

When cold started the glow plugs burn for a minute, while they are on the voltage will be low, once they kick off it jumps right up. Normal operation.

^^^ What he said ^^^

well that's good to know . now on cold start up i am getting a lot of gray smoke . am i looking at replacing glow plugs

Well, I learned something today. I always wondered why I was out of the driveway before the lights would suddenly brighten. The genius at the auction place where I bought the truck said the computer ran the alt, and wouldn't let it charge for 2 minutes. I figured he was wrong, but I didn't know why. The trucks sit in the auction yard for months, and the batteries are stone dead and wrecked, and when they boost them, they have to leave the cables on for a couple of minutes so the trucks will keep running.