Alternator or.......?

[Snake]

Pulled away from an intersection last night and got on it a little bit because the truck sat for a couple of days. My battery light came on just as it shifted into 3rd gear and when I looked down at my gauges confirmed that I was only getting 11.9 - 12.2v. Literally right before that I was at 13.8 - 14.0v. Batteries are two week old DieHard Platinums and the alternator is a 200a large case unit from alternatorparts.com (probably 3 years old).

Am I looking at a new alternator, or is there something else that I should troubleshoot first?

 

[Mdub707]

Why not just pop it off and get it tested at an advanced auto or something, they do it for free?

 

[F-250-Owner]

did the battery light go out? I look at the alternator first... Im sure you know how to check it with unhooking the batteries.....

 

[F-250-Owner]

Why not just pop it off and get it tested at an advanced auto or something, they do it for free?

alot of times the local parts store cant test them because they are too big... at least thats what I have been told when asking to test one.

 

[Snake]

Battery light came on and stayed on. Just went and double checked and yep, it's still on and showing 12.2v on the ScanGauge II.

Read voltage off the back of the alternator with a multimeter while the truck was running......12.2v. FML.

 

[Snake]

alot of times the local parts store cant test them because they are too big... at least thats what I have been told when asking to test one.

I've heard the same thing, and even if they could test it I really didn't want to pull it off only to find out it's ok and that I should have been looking elsewhere for the root cause.

 

[yeehaw]

All the connections tight??

In the slow duramax

 

[PowerStrokeEnginuities]

just get a dvm and see what it charging at with all the acc's on, check amperage out put also.

 

[Atsah]

Battery light came on and stayed on. Just went and double checked and yep, it's still on and showing 12.2v on the ScanGauge II.

Read voltage off the back of the alternator with a multimeter while the truck was running......12.2v. FML.

I would say the alternator is junk Snake.. I never had much luck with autoparts store electrical stuff..

 

[faster6.0]

alternator.... do it now before you kill a battery or two.

 

[F-250-Owner]

his is a 200a from alternatorparts.com. Hope it has a good warranty.....

 

[Snake]

All the connections tight??

In the slow duramax

Yessir. That was the first thing I checked last night, especially considering I just installed new batteries. Always a chance to overlook something or not snug a connection down. Course that's not how my luck goes. LOL

just get a dvm and see what it charging at with all the acc's on, check amperage out put also.

I read 12.2v after the gp's cycled. No other accessories on. Haven't checked the amps yet and might do it just for grins, but I'm pretty sure the alternator is tits up.

I would say the alternator is junk Snake.. I never had much luck with autoparts store electrical stuff..

Honestly, I'm not too sure what to think about this one. Bought it from alternatorparts.com probably three years ago, and it worked flawlessly until last night. No warning signs, no weak charging, nothing at all that would have indicated it was on it's last legs.

I'm up in the air about what to replace it with, but the two front runners right now are DB Electric (220a unit) or DC Power.

alternator.... do it now before you kill a battery or two.

Definitely! I learned that lesson the expensive way a few years back. Didn't realize my alternator was barely charging my batteries and ended up taking out the batteries, the FICM, and a couple of injectors. The truck will end up sitting in my driveway until a new alternator is ready for install.

his is a 200a from alternatorparts.com. Hope it has a good warranty.....

12 month warranty, so I'm SOL.



Thanks for all the replies :fordoval:

 

[rake18]

sounds like the ALT, sounds like the Bottom Brush on the Regulator is worn out, common on any ford alternator brushes are usually the first to go.

 

[Atsah]

sounds like the ALT, sounds like the Bottom Brush on the Regulator is worn out, common on any ford alternator brushes are usually the first to go.

It's not a FORD alternator oke:

 

[F-250-Owner]

how about rebuilding it? is there a local shop around or can you do it? it sounds like it has worked great for 3yrs.....

 

[Snake]

I hadn't considered that, but that may be an option. I might order a new alternator from DB and see if this one can be rebuilt. With the 6.0, it never hurts to have spare parts readily available. LOL

 

[F-250-Owner]

true that.......

 

[Snake]

****UPDATE****


Ordered a 220a unit from DB Electric and installed it Friday evening......aaaaaaand I'm still at 12v or less on the ScanGuageII. Began troubleshooting and here's where I'm at:

-- Still reading 12v or less off the threaded stud on the back of the alternator

-- Battery light comes on with KOEO, and goes out when I start the truck (voltage is around 12.6 - 13.0 at idle after the glow plugs finish their cycle)

-- Disconnected batteries and each read 12.3v (keep in mind I haven't re-charged the batteries since the night of the problem)

-- With everything connected, I'm reading 0.3v from the threaded stud on the back of the alternator to the positive terminal of the passenger battery, so I know I'm not losing voltage across that wire)

-- I unplugged the three pin / two wire connector from the alternator, started the truck, and check for voltage on both pins: 11.74v on one, and 12.0v on the other

-- Double checked all the fuses in the engine and under the dash again, just in case

As of now, the only two things I haven't checked are the amp output of the alternator and load tested the batteries.

Other than these two things, what else could I be missing?

 

[Atsah]

All your cables connections okay?

 

[Snake]

Yessir. I was running Optima blue tops prior to this and didn't have a spec of corrosion. All connections are snug and secure.