130 amp Taurus overheating
 

Hi guys. If anyone's been following, I recently put a ford 3G alternator in my S4. I have the wiring 100% figured out, got the alignment correct, etc...

Now I think it's overheating. It puts out around 15v at idle, and will stay that way for a few miles down the highway, but after a while, the voltage drops off and the battery eventually dies. If you let it sit for about an hour it fires up and holds voltage. Tonight is the 4th time this week this god damn car has stranded me. Twice with my 11 month old son in the car.

Has anyone had a similar problem, or might know what the problem is here?

I think that the regulator might be fried. it is replaceable as far as I know about $60.
You might also be underdriving it with a smaller pulley? could make it over heat.

I put a slightly larger pulley on it, but I'll look into the regulator.

It might be worth mentioning that I bought the Taurus alt brand new before installing it. It is not a used unit.

whered you get it? some auto parts stores have lifetime warranty on them, just get it replaced

yeh thats true too. I did also buy mine brand new and the regulator crapped out when it was on the dyno for the first time, and the regulator was the culprit.

As Hypertek said just get it replaced if it has warranty for sure. May just be a lemon.

I tried. If anyone else has done the swap, you know that you have to grind a bit off the one ear to make it line up. They saw that and refused to take it back. I have a regulator I could swap out, I'll see if that works.

Could a bad battery cause that problem, if the battery was bad and the alternator was putting out too much attempting to charge it?

After starting my car, it sits around 14.7V-15V. After ten or so minutes, the voltages drops to a steady 14.3V... But runs and stays charged just fine. I assume mine does this due to using the stock belt. I've not yet installed the longer belt, and modified the black bracket.

I don't see what a different belt will change...either the alt is spinning or it's not.

Well, the guy who had his Taurus alternator method just recently archived (Chwkrx7), shows how he extended the black bracket and put a longer belt on... I guess he did this so that it was easier to get the belt on. But I was able to get the stock belt onto the alternator pulley with a bit of tugging. I thought maybe the shorter belt was "over-revving" the alternator. Other than the high voltage at times, it works just fine.

I could use the stock belt, but I got a 1" longer belt due to the larger pulley. I tested the alternator at idle and it says it's putting out 29.3 volts....

29.3 volts at idle???? For the love of everyone here, toss that alternator into the garbage, go to the junkyard and get a new one. If you mount it like I did, there will be no need for grinding on the case.

Your regulator is fried. Don't start the car untill it has been replaced or you WILL fry everything else with a circuit board in it.

Did you follow my diagram to wire it correctly?
http://i619.photobucket.com/albums/t...torUpgrade.jpg

Terminal A goes to the battery, Terminal I goes to ignition switched 12v, Terminal S loops back to the stator. Putting the sensor wire (Terminal A) on anything other than the battery will tell the alternator that it's not working hard enough and if you're lucky, will blow the main fusible link. This is why the main fusible link is rated at 80 amps on a S4, to protect against an alternator with a failed or disconnected voltage regulator. For a Taurus alternator, a 100 amp one would be sufficient.

youre seeing 29 volts on a meter i assume. what is the factory gauge saying?

I found the problem...

The thick wire that goes down to the starter had a slice in it, which and it looks like it shorted off the throttle body, and melted it in half. I reconnected the wire and all is well.

I'll be upgrading to a heavier gauge wire before I do any more heavy driving.

According to Aaron Cake, using the starter as a distribution point will introduce noise into the electrical system. Plus, the alternator has to work harder since it runs down to the starter and then back up to the battery. Remember, the alternator's output cable should be a straight line to the battery and be as short as possible for minimum voltage drop. 3ft of 4 gauge battery cable is plenty for this task