I just swithed out the alternator on my 95 Discoooo, and the new one is all great but there's a minor problem, the tach sits at 500 until the engine is warm then will kick in...Im thinking the belt maybe a little too loose, but the darn tensioner is an automatic tensioner...

BTW, also just changed brakes/rotors and i hate life cause it took 1.5 hours each, and i'm a pretty damn good mech...(Appx Cost If dealer installed = 80PerHour @ 3 Hrs =240.00 saved...)

 

Problem solved via Pulley diagram...Note that a tech told me, the belt (on the alternator) should always be in contact with atleast 90degrees of pulley... awsome, thanks wise people for being wise and such..