Alternator not charing battery (dt466)

[Seeria]

SOLVED
Problem solved.
A recap for others that have similar problems. Batteries weren't getting a proper charge but alternator seemed to be working so after numerous talks with mechanics and forum folks, it was most often guessed the regulator was the problem.
After taking the vehicle to two shops in town, one an alternator specialist, we found that to be the problem. Our dt466 diesel international had a relatively new (6mth) old alternator which has the regulator inside. The alt was a "private label" from International, which we were told by a Int dealer this particular one tends to have regulator failures.

Replacing the alt with a brand new one fixed the problem of it sometimes not charging the batteries or charging barely enough.


Good thing for us is the alt was under warranty so total cost to replace was $30 (loved that...no full hour rate charge), took 15 minutes.

Hope this helps others with similar problems!!



-------------original --------------
Hello everyone! I've ran into a weird problem with Fran. She's sat for about a week and temps here are 50's days, 40's nights and we're on the coast about a mile from the ocean.

Went to start her and the beeps that go off while warming up (glowplugs) before cranking the engine were not the usual noise but a higher pitch beep. The voltage gage (think that is the name) says she's at 12 (black area) when she usually sits just over 14 (green area). She did start without a hitch though, ran her for about 15 minutes before turning her off.
Too scared to drive her as we're living in her, so if she breaks down I have to get a tow and not sure the campground we're in would allow us to sit here with a vehicle not working. Sure can't afford a mechanic at the moment.

Any suggestions on what the problem might be? What to check for, clean, test. The alternator is brand new this summer. Battery cables are a bit old but seem in good enough condition. One battery is new, one old (yeah I know... shame on me). Suggestions, please

[bus-bro]

Can you put a battery charger on it, and see if that changes the sound. A 3-stage battery charger is invaluable. I have a 8 amp Battery Minder and that thing has solved most my battery issues.

[Dain]

I tested it with a multimeter today, the batteries appear to be fully charged, but they are not getting anything from the alternator. The alternator is about 6 months old now so I doubt it's dead yet lol so I'm thinking wiring, but I'm not sure where to start on checking those.

The beep didn't sound too far off this time though. We do have a charger, will probably have to plug it in to make sure they are topped off.

[opus]

Sounds like your beeper is going bad. Mine did that....still does at times.

[Seeria]

heh I thought the same thing but that doesn't explain the drop from a 14charge to a 12 on the meter.

[wtd]

I was thinking the charger was good for given them a bump, but what's making them go dead in the first place?
Did you check the current draw on the batteries when the bus is off, take off one of the battery leads and stick an ammeter in there? Shouldn't be more than a couple hundred mA, for the radio and whatnot.
Far from a mechanic, just that's what occurs to me - start at the beginning and work out.

Tom

[opus]

Originally Posted by Seeria

heh I thought the same thing but that doesn't explain the drop from a 14charge to a 12 on the meter.

Sure it does...its shorting out while its doing it.

[bus-bro]

I had a 30 amp ground in the altenator cable on my bus. Usually I turn the battery switch off, but one day I was working on the bus and had the radio on. After about 30 minutes the radio went off. WTF? Found out I drained the battery. Did a resitance check between the positve lead and ground, 0.4 ohms! Then I disconnected the big wires from the power post, and checked the resistance to ground on each cable. Found the ground on the altenator cable. Wiggled the cable, and the ground went away. Guess I better fix it. Thanks for the reminder.

[opus]

When I park my bus I ALWAYS shut the master disconnect off. Most all buses have them.

I dont have any drains but I do it as habit, just incase something decides to happen.

[Dain]

We took her out for a test run yesterday.

When we left the batteries showed a 12.7 voltage on a multimeter. As she drove the dash panel voltmeter showed 12 with occasional dips when she ran blinkers or brakelights. When we stopped the batteries were down to 12.45 on the multimeter, letting her idle while See was in the store the batteries went back up to 12.58. Back at the campground she's running a the same. Setting them up on a charger now.

The alternator is producing electromagnetic field, so it is doing something from whaat I understand. It is just not making it to the engine/batteries.

All I have for testing now is a digital multimeter (without an amp testing setting). Any ideas where to go from here?

[wtd]

When the bus is running the voltmeter on the bus (or measured at the batteries with a multimeter) should be something north of 13 volts.
So I'm not sure where you get this ...

The alternator is producing electromagnetic field, so it is doing something from whaat I understand. It is just not making it to the engine/batteries.

I'd suspect the alternator.

[chev49]

Previous post is correct. Also, you can pull the alternator and take it in to autozone, etc. I don't remember if kenect's tests them as he was originally from Greenacers by Coos Bay. And if you want a cheap 12v alternator that is new, you can install a 1 wire GM alternator -the late 70's one, and get a higher amp one instead of paying 300..... Of course you can take a lawn mower with a pulley and a cheap 1 wire chev alternator and make a great 12v generator... but thats not part of this topic.

[Dain]

We are taking her in to check soon, can't do the alternator ourselves here.

The magnetic field idea was from a guy at the local marina who works with heavy trucks and farm equipment.

One thing that keeps popping up in other avenues of research to test is the voltage regulator (Supposed to tell the alternator to kick in/increase output). That it could be a separate unit, or part of the alternator depending on your model, and that it is a common cause of problems when the alternator is actually working. Does anyone know where that would be on this model? Trying to minimize the amount of time spent in the shop.

[Stuff]

this is what i got. saved my new replaced batteries. luckily warranty covered the first pair that were killed from letting it sit over winter hooked up..

[frank-id]

As pictured, cable disconnect will not carry the 12-1500 amps required for engine starting. Easy method is removing any cable.
Best method for over winter storage is trickle charger and 24 hour timer. Charger comes on 2 times per day for an hour or two.
Fully charger battery is 12.6 volts............. Frank

[opus]

Most school buses have a master disconnect switch on the frame.

[wtd]

Originally Posted by Dain

...
One thing that keeps popping up in other avenues of research to test is the voltage regulator (Supposed to tell the alternator to kick in/increase output). That it could be a separate unit, or part of the alternator depending on your model, and that it is a common cause of problems when the alternator is actually working. ...

You most likely have a 'one wire' Delco alternator, the regulator is internal.
The alternator is generally viewed as a 'works or it don't' part and replaced as a unit, rather than replacing components within it.

Tom

[Dain]

Originally Posted by wtd

You most likely have a 'one wire' Delco alternator, the regulator is internal.
The alternator is generally viewed as a 'works or it don't' part and replaced as a unit, rather than replacing components within it.

Tom

Ours has a red cable, a white cable, and a small green wire running into it. Is that a one wire?

[wtd]

Ours has a red cable, a white cable, and a small green wire running into it. Is that a one wire?

Got me That 'one wire' thing's kind of a misnomer, sorry. Most have a coupla wires coming off of them. I was kind of 'assuming' since the few dt466's I've seen had Delco alternators on them.

Doesn't it have a tag with manufacturers info or maybe a name/number stamped in it somewhere?
Would be easier knowing what brand it is.

[chev49]

above pictured disconnect will work, but i have found that they often corrode between the two parts, which aint good cause the engine might not crank over, etc.. For many years now, i have put regular high amperate disconnect switches that turn batteries off on little used heavy equipment. They aren't cheap, but work excellent.