Alternator woes

[natjwest]

Truck is a 2000 K2500. I am on a road trip and concerned about charging.

On Wednesday morning, it was 15 degrees and the engine took four separate crank attempts to finally fire up so I'm sure the truck batteries were quite low. Having to charge four batteries (two in the truck, two in a camper I'm hauling) was apparently too much for my alternator. In retrospect, I believe the batteries weren't fully charged at that point due to alternator problems.

After a few hours of driving the symptoms were: turn signals speeding up/slowing down, radio clock blinking on/off, dashboard voltage gauge getting into the orange, truck failed to start at a pit stop requiring a jump start, the auto transmission would not shift out of first gear, and finally when I release the accelerator pedal, the revs would jump around like the fuel injector was freaking.

I made it to San Fran on Wednesday night and then on Thursday morning, after a rest, it fired just fine and everything ran normally for about 20 minutes when (I think) the alternator heated up and the turn signals started blinking fast/slow. The tachometer gauge has been acting freaky for a little while (a week or so). I have read here that the truck's tach is run off the alternator so that should have been a signal to me.

On Thursday, I took the truck to a shop and, after charging the batteries, they found low voltage coming from the alternator at idle and at revs, just like I suspected. I also have a Surepower isolator (12023A) but I am not sure if they properly tested it. There was a remanufactured Delco, I believe 100 amp in there. The shop replaced the alt with another "stock" remanufactured 100/105 amp in there.

I didn't use the truck much on Friday or Saturday but last night I had a longer trip in the bay area (an hour) and the tachometer started misbehaving occasionally and the volt meter in the dash isn't staying up near 14, more like the bold line at 1/4, closer to orange. On both Friday and Saturday, the when starting the truck, I did not get a great feeling. It did not jump to running like it's done in the past.

I just did some voltmeter testing. First disappointment was one battery at about 12.5 and one about 12.2. Knowing they should be darn near the same voltage, I checked the cables and one battery's negative terminal wasn't connected at all. After connecting it, the batteries leveled to 12.3 each. After making that connection, the truck does jump to life as usual. Voltage from the alternator (red on alt, black on battery terminal) shows 11.34. When running, the batteries are showing a lower voltage than when off, so I think the truck is pulling power from the batteries since the alt is not up to snuff.

I just dropped the truck off at a different mechanic than the one that did the alt replacement on Thursday. Is there anything I should be aware of beyond simply testing the voltage and amperage coming out of the alternator? I have thought about rewiring the alternator output to bypass the Surepower, but the voltage is looking fine through that isolator (just a couple points drop). There is no load on the other side of the isolator - I have unplugged the camper from the truck until this is sorted out.

Sorry if this is too much information. I'm a bit of a beginner when it comes to this truck.

 

[NVW]

Have them load test the batteries, bad batteries will over tax an alt.

Also make sure the alt has a pulley for a diesel, did your tach have the correct rpms? If it did you probably have the correct pulley.

 

[natjwest]

Have them load test the batteries, bad batteries will over tax an alt.

I believe the Thursday shop tested the batteries and said they were okay. They are about six months old also. I think the over-taxing came from having to charge my camper batteries too much.

Also make sure the alt has a pulley for a diesel, did your tach have the correct rpms? If it did you probably have the correct pulley.

Prior to these problems, the tach always appeared dead-on.

 

[THEFERMANATOR]

Also a shorted armuture inside the alternator WILL kill the batteries as instead of charging 100 amps it can discharge it. And with that many batteries I wouldn't run a 105 amp CS-130 alternator(stock alternator). I would step to a AD244 alternator at 130 or 145 amps as they can handle putting out at capacity for extending periods of time. I run REMY alternators from ADVANCE auto parts. I run the REMY 91606-WU on my DURAMAX and have never had a problem with voltage even with all 6 lights on, both airs, and the electric cooling fan in the BURB even at a 600 idle. It also came with the correct size pulley for teh alternator to make the tach read correct.

 

[Matt Bachand]

AUTOZONE gold alternators are lifetime replacement and can be swapped anywhere, meaning chainwide buy one there, and you can warranty at your house if you have autozones.

I have plowed more this year than the last 2 combined, and this is my 2nd plowing season on my AUTOZONE alternator.

I have over 60 marker lights, and the plow draws SUPER amps, and the alternator is running perfectly now for 1.5 years.

I recommend them now, even if they are made in MExico. I guess its better than VaChina.

 

[natjwest]

Okay on Autozone, I found one locally. PN DLG1468-16-4. Delco Remy 140 amp ext fan

Is it external or internal fan? I could guess internal. Please let me know guys, thanks.

 

[nobby]

What Fermanator said that many batts upgrade your alternator. In your case I would install a true hot rated alternator rather than a higher output automotive style unit. One that can charge at an appreciable rate at lower rpms and quickly and not mind getting hot so that when camping and using them overnight you can bring them back quick the next day. Also preferably one that is externally regulated. Check out the ones for the marine field you are in effect operating like a boat.

I also hope that having 4 batts you in effect have 2 dedicated for starting and 2 for house loads and they are normally isolated when not charging. That way you should normally always have full batts to start with.

Oops my apologies just noticed you mentioned isolator sorry. Personally I am not a big fan of isolators unless you are taking a voltage sense from the battery side of the isolator. They in effect because of the voltage drop you already mentioned across the diodes technically always undercharge the batteries.

What actual batteries do you have for the house, knowing there capacity will help in deciding the capacity of Alt required. You'd be a good candidate for the second alternator install.

Cheers
Nobby

 

[THEFERMANATOR]

Okay on Autozone, I found one locally. PN DLG1468-16-4. Delco Remy 140 amp ext fan

Is it external or internal fan? I could guess internal. Please let me know guys, thanks.

External fan will be a CS-144. It will require an adapter or a change of the alternator plug to run it on your 2000 if you currently have a 105 amp one. The Ad244 available in 2001 on teh DURAMAX is a direct replacement for teh earlier Cs-130D 105 amp but with higher output and most all of the weakness's corrected. As for teh AZ alternators, I was losing money on them here recently on warranty work so I quit using them unless the customer requests them and understands I will NOT replace them under warranty down the road for them. I do alot of sidework and warranty everything I do, but AZ's parts caused me to raise my labor rates 50% so I could make money as roughly 50-60% of the parts I was buying there would fail in the first year(I was going through alternators every week there for awhile from them on a friends work vans he uses for fleet work). REMY isn't much more money and is also lifetime warranty at any ADVANCE nationwide.

 

[Matt Bachand]

His advice is worth 100x what mine is I'd even listen to his advice next time around.

Either way, if it were me I'd buy a new alternator from either chain no matter what and take it from there. Having the batts load tested is also just as important. A dead one can take out the rest. and the alt.

 

[natjwest]

Thanks fermanator. With the help of a particularly bright sales guy at Kragen, we were able to deduce that the 2001+ silverado diesel alternator would fit, which looks just like the AD-244 you mention. We could not find anything in their parts computer for the 2000 diesel 2500 above 100 amps with internal fan. Glad to know I made the right decision. I will go back to kragen to get the batts load tested as soon as the mech is done with the job. I bought the batts from kragen too. Great service here guys, glad you're available to help a n00b like me.

 

[THEFERMANATOR]

The internal fan wasn't available on the old body style trucks in over 105 amps, it didn't come out until 2000 in teh 1500's and 2001 in the 2500/3500 chassis. It is a direct swap in though, and is a MUCH better outpout alternator that GM is still using(they just swapped regulators over to a 2 pin instead of 4 pin plug).

 

[colbythekid]

Make sure that when they load test the batteries that they are disconnected from each other.

Colby

 

[handcannon]

How does the Ad244 compare to the CS144? Turn on RPM? Low RPM output capability?

Don

 

[THEFERMANATOR]

How does the Ad244 compare to the CS144? Turn on RPM? Low RPM output capability?

Don

Pretty simliar as far as I know. They are basically the same rotor design and are the same rotor size and case diameter. I believe both are rated to put out close to 70-80 amps at an idle, and reach rated output around 1400-1500 engine RPM's. The difference I read was that the AD-244 is SEVERELY under rated in it's power output. They are supposedly able to put out close to 200 amps if you can keep them cool enough, but the output drops off sharply as the stator heats up. The CS-144 is a pretty flat output from what I could tell. I know the AD-244 on teh DMAX puts my old CS-144 to shame that I had on the 6.5 for output. The only time, and I do mean only time I don't hold over 14 volts is during a cold start and the glow plugs do there after burn. Even the intake heater won't pull it down. And if I give it even a little throttle it can keep up with the glow plugs no problem. That's alot of output since teh glow plugs draw about 110 amps.

 

[nobby]

The difference I read was that the AD-244 is SEVERELY under rated in it's power output. They are supposedly able to put out close to 200 amps if you can keep them cool enough, but the output drops off sharply as the stator heats up.

Sounds like it is running in a sweet spot then if you are demanding 3/4 of it's possible output then from a longevity standpoint. I am assuming a 150A or thereabouts rating here. Even with the ext reg heavy duty hot rated units that I install I try to size 2/3 to a 3/4 of max possible output to get life out of the units. Although I have run 300A J180 large diode hand wound units at close to that in hot enviroments and still get OK life out of them it certainly takes its toll.

Cheers
Nobby