Question about alternator..

[diezelman]

Hey all,

Maybe you all can point this one out for me on my 98’/3.0/4x4/Danger Ranger with 47k original miles.
I have had a terrible squeal noise coming from a pulley, or the belt, I was finally to the point of utter embracement driving this thing through traffic that I decided to trouble shoot the problem. So, I bought a new belt, pulled the old one off, and started spinning the pulleys trying to figure out were the squeal might be coming from. I concluded that it was the alternator, so I took it off, went to my local O’Rileys, and purchased a brand new one and a bottle of orange Fanta. Once I get the new alternator on, all the plugs back in place, struggle with the belt, re-connect the battery and presto everything is good to go, no squeal.
I take it out for a drive around the neighborhood and I notice the battery light is on, so I park it and rev it for awhile, the light goes away, the battery gauge is center spec, but as soon as I take my foot of the gas it drops back down, and the light is back on. It is like the battery will not hold a charge at all. So I swap the battery with a brand new one, still the same problem. It seems like alternator only puts out power if I am running at 3k plus RPM’s.
I have checked, double-checked, and triple checked all my connections. Is this a case of just a bad alternator? Or is there something that is obvious that I am missing? I am convinced it is a bum alternator, but thought I might get some other peoples advice before I do that whole process again.


Any feedback is greatly appreciated folks, thanks again!

JP

[12Ounce]

It's a good practice to have a new/rebuilt alternator's output checked at the store before you leave with it.

I have seen them bad right out of the box ... should have 14+ volts at output terminals.

You should now check voltage across the battery terminals while engine is idling ... should be 14 volts or better.

(... and stay away from that Fanta!)