HO Alternator woes

[B94Sport]

Now this one has me stumped...
I got my new 200 amp alternator from mralternator.com today and promptly installed it. Start the truck, and the battery gauge drops all the way down to the "N" on NORMAL and continues to fall. I figure they sent me a bad alternator. So I put the old stock alternator back in and it charges the battery. I go to Autozone to get the 200 amp tested, and their machine says it's putting out 14.5 volts! :frustrate How could this alternator be working on the test machine and not work in my Explorer? The Autozone tech mentioned something about a stater?

 

[williecume]

e-mail the mralternator.com and see what they say. and if you find out anything please post.

 

[88vert]

What did it run you for that alt.

 

[B94Sport]

$235. I am calling them again tomorrow. I tried switching the 3 prong connector from my stock alt to the new one and that didn't change anything, but I did notice that the pulley on the new alt is much smaller than stock and the belt is squeaking. I am going to switch the pullies and see if maybe there wasn't enough tension in the belt to properly turn the small pulley.

 

[RFR2212]

Yea, I had a similar problem... I got my from the mechanical man. I sent it back, they did a lil tinking on it, and really it was fine, there was a lil bit of metal that needed to be ground off.. but it woulda worn away... The pulley should be smaller... It allows em to spin faster I believe... To stop squealing... throw some belt grip goo on it. The low charge... mine showed that at first.. but it built right back up. Do you have bigger power wires to connect the alternator to the battery? I've got 1/0 gauge wires running from both the positive and negative on the battery to the alt to allow the power to flow better.
Pete

 

[B94Sport]

Hmmm... Well I can try the belt grip stuff I guess. I know the smaller pulley lets it spin faster, and I would probably lose a lot of amps if I switched them. I just realized I can't get either pulley off so I am stuck with the small one. As for the low charging, mine drops, continues to drop, and never rises again - even when I rev the engine.

 

[B94Sport]

An update...

I have no idea how this happened, but suddenly the alt is working. I put it back in this morning and decided I would try to go find a smaller serpentine belt... So I drive to Autozone, and on the return trip, I look at my battery gauge and the needle had actually moved up! By the time I got home, it was fully charging the battery, just like the stock alternator. Now I just need to find a smaller belt that will fit on all of the pullies so that that horrendous squeak stops... Weirdest thing I ever saw.

 

[Alec]

Can't you adjust the tensioner for just the little bit of slack it need to take up? You might be able to do that instead of getting a new belt.

 

[RFR2212]

The tensioner should be automatic, cause they've got some spring preload to em, sorta... Unless there's a way to manually adjust them as well...
Pete

 

[Alec]

Dunno, somehow my mechanic was able to adjust my tensioner to apply the correct tension for my new longer belt for the s/c.

 

[B94Sport]

My tensioner is spring loaded and as far as I can tell, it is extended as far out as it will go. The belt is gradually squeaking less, perhaps eventually it will stop. None of the belts I found were the right size, the next smallest size is too small to get on. Oh well, at least the alt works!

 

[mahieber]

I bought a 200 amp and was worried about the belt length after reading all the threads about the smaller pulley. I called my auto parts guy and told him I had an 87" belt and I needed one about 2 inches shorter. He is holding a 2200mm/85" belt for me to pick up in the morning.