04 x 6.0

Had some alt problems lately, the battery light has been coming on a lot lately. my scanguage has been showing 12v when the light has been on and the lowest it goes is like 11.6 but won't go over 12. but then after about 20min of driving or so it'll go back to normal so i figured it had to do with the glow plugs but now the light is flashing all the time and it goes from 12 all the up to 16.4. I have been driving the wifes vehicle so that i don't fry my 6 month old optima yellow tops. I'm assuming the voltage regulator is burnt up in the alt since i hadn't seen these problems.


Been looking at this since its still got the stock alt.
6G Series Heavy Duty Bridge Rectifier High Output 140 Amp Alternator

any input is appreciated. Thanks in advance

Camdon

 

Nobody has any input?

 

You want opinions on the alternator replacement choice or if the problem is indeed the voltage regulator?

My opinion is that the alternator does need replacing and that 140A is a good choice. Although, I'm a power nut and would probably opt for the 200A and add a 250ah battery for shore power that powers a 2000W inverter for those long days at the track..

 

Well I replaced the Alternator and i'm still getting the battery light. Also it won't let my truck charge past 12 volts. I have read that the glow plugs can stay on for a max of 2 minutes before the computer lets the alt do more but this stays on longer than 2 minutes. and if im city driving it starts to drain more than it will let it charge. it seems like it has to do with one of the computers but which one? I'm stumped

 

What have you done so far to diagnose your charging problem? Have you put a multi-meter on on your batteries with the engine running? Have you checked the body ground?

Stewart

 

Well i have my scanguage going and showing me my voltage. which won't go above 12 unless i drive for half an hour and then it kicks the alt on. grounds all seem to bet good. I'll double check and add some new ones. the batteries are like 6 months old so i don't think they would be bad but i guess i'll pop them out and load test them. It just doesn't seem like the batteries should cause a problem like this.

 

Disconnect the ground, clean the body and terminal end, add a dab of Noalox and reattach.

I wasn't thinking it was the batteries, I was thinking it might be your cables. If you replaced the alternator, and it's working fine, I'm wondering if the cables are carrying the charge to the system.

Stewart

 

My work truck is doing the same thing. Got a new alternator today and it still only shows ~12V. It's an 04 F-350 with the 5.4L V8. (Don't think it's a glow plug problem.).

 

Well i was thinking it was glow plug because it doesn't let the alt come on until it cycles the plugs off.

 

I just don't get why it would charge to 12 and not past that. then after 20 min or so it goes back to working like normal.

 

Have you posted in the 6.0L PSD forum too?

Stewart

 

Not yet because I was told that the gem module on the excursion isn't the same as the SD's. and the PSD excursion categories nobody ever posts answers to questions lol

 

Just throwing it out there, but I am in a similar situation. My Napa alternator **** the bed and supercharges the battery at 2500+ rpm. Voltage regulator is dead. Last week it started to not charge at all until I was at higher rpm and idle would be running off battery power at 12V.
I ordered a new dc alternator and in preparation have upgraded my battery wires.

added a 2 gauge wire connecting the 2 batteries, driver side battery got a new 2/0 ground wire to the same fender location after some cleaning, passenger side got an extra 1/0 ground to the frame in addition to the stock engine block ground. Then I added a 1 gauge wire between the alternator and the battery while retaining the tiny stock wire as well.
Just this has greatly improved my charging capacity and now charges at 13.6V at idle (still overcharges at high rpm) but I believe the cause of the low charging to be corrosion and resistance in the factory wiring.
I would recommend cleaning all ground connections and and corrosion visible.
Good luck and I hope you solve this!