Weird Alternator problem

[ByronCR]

So I have been searching and reading several other threads on alternator issues with the 6.0L and so far I have not been able to figure out mine.

Alternator is a Motorcraft 110amp single remanufactured - only 2.5 months old

When I start up my truck, I am able to keep track of the battery voltage from the alternator using my Edge Insight CTS. It typically is at around 11.5v - 11.9v when I first start up the truck and usually after about 1 minute it jumps up to 13.5v -14.1v and this is what I would expect. The odd part is my battery light will come on and stay on for approximately 5-10 miles and then will go out, but occasionally going down the road it will turn on again and then go off in another couple of miles.

Just recently it has decided a couple of times not to start charging at all. The battery voltage stays at about 11.5v -11.9v and even after 5 min of driving and at freeway speeds its not kicking up. The first time I pulled over, unplugged the 2 wire plug and kinda jiggled the wires around and checked all connections to the batteries and then started up the truck. It returned to normal working order. So last night I went to the gas station, filled up, started up the truck and would not kick into charging mode. Drove the 5 miles back to the house and tried unplugging the alternator and and jiggling the cords. Did not fix the problem. I tried checking all the wires again and everything is secure.

Went out this evening to try the truck and everything is back to charging, but still with the annoying battery light.

The last thing I am going to check is grounding wires, but other than that, I am out of ideas. Any suggestions would be greatly appreciated.

[dannyboy950]

Take it to a alternator/starter repair shop and have it load tested. It may have an internal regulator problem.

Did you verify your readings with a dvom and not just the ensite?

[Chad29860]

I went through 3 new alternators and then finally ordered I high amp alternator and havent had any problems since. I ordered the 270 amp alternator from Mechman alternators and she is a nice unit stays around 14.2 volts all the time even with ac on, headlights on and my stereo cranked up and amp drawing alot of power.

[ByronCR]

I did a load test with dvom. I also had my dad who is an electrician do the testing just to make sure things were tested correctly. I wasn't sure it sounded like the regulator in the alternator or not.

I was contemplating getting a high output alternator and seeing if that fixed the issue and then having the motorcraft rebuilt. Just didn't want to fork out that much money unless I was more sure about the issue.

[ByronCR]

So after going through and cleaning and checking all connections and adding a couple redundant grounds, Still having the stupid battery light issue which makes me believe the internal regulator is probably crapping out.

I went ahead and ordered a HO Alternator from DC Power (185 amp) to see if that rectifies the problem. I can also have the motorcraft one rebuilt as a backup. If the new one fixes the problem then awesome, if not......I will have to really start trying to figure out what is causing the problem. Will post an update after I get the new alternator.

Thanks again for those who posted suggestions.

[Chad29860]

Your not running a amp and subs and all are ya? If you are a 185 probably wont be enough. These trucks hate low voltage and it can tear alot of stuff up.

[dee004]

I have a very similar issue. Subscribed. Please keep us posted

[ByronCR]

Cha29860,

I'm not running any amps or subs, just the stock stereo system. Actually I am not running any aftermarket items that require power besides my Insight CTS. The only thing I might be hooking up to my truck in the near future is my travel trailer.

[Chad29860]

Originally Posted by ByronCR

Cha29860,

I'm not running any amps or subs, just the stock stereo system. Actually I am not running any aftermarket items that require power besides my Insight CTS. The only thing I might be hooking up to my truck in the near future is my travel trailer.

Thats good just checking cause when I had my problem it was my system killing my alternators i believe. Also check all your factory grounds make sure they are in good condition and not loose. They had a recall on one of the grounds on the early model SD's might wanna check and see if yours has that recall and see if its been done. I ordered my alternator from Mechman Alternators, cant remember where they are from but they were real helpful and havent had a problem since I installed their alternator. I bought a 270amp figured i would have plenty of amps, the alternator is only gonna put out what your truck needs and I figured the bigger alternator wouldnt work as hard as a smaller to produce what my truck needs. Now with system cranked and ac on high my headlights never dim.

[ByronCR]

Yeah I checked the grounds and everything looked good. I even added an extra ground wire from the engine to frame and another ground from the frame to the body. Was just trying to make sure there was a complete ground.

Also I went with the 185 amp due to the fact of budget, and I don't plan on running much more than a couple of small aftermarket accessories later down the road. If I upgrade to a winch and aftermarket lights I will look into bumping up to a larger alt. I am just hoping that the bigger alt will fix the issue.