Charging System Question on a 90 D250

[PGunther]

Please forgive me as I am posting under my friends logon, but we are having some problems with the charging system on the above truck.



Here is the scenario... a while back I was driving said truck and I noticed I was loosing power on the gauges... when I noticed it was probablly around 11 volts. By the time I got it home, I had nothing... it had totally drained the battery.



After making some quick checks I don't see anything out of the ordinary. So the first thing I do is charge the battery and throw the battery tester on it. It immediatly pointed at the charging system.



So I start off by checking connections, cleaning posts on battery, checking the grounds and cleaning other connections. Still nothing.



Next I put a new reman alternator on it and still the same results. Tester still says there is a charging system failure. I am only getting charging volts off the alternator at where the battery is charged to at the time. Say the battery is at 12 volts when not running, I get the same off of the alternator once is started. If the batter is running dead and is at 11, then the charging volts is 11. Running the truck turns into running the battery down without the alternator recharging the system.



My next stop... voltage regulator. I find another used regulator around the shop and the resistance on the 2 regulators are different. So I swap the regulator hoping that I fixed the problem. Battery tester says good to go. Charging volts where it should be. I am getting 14+ volts from the alternator. Drive it for a couple of days with no change. Still get 14+ volts. I drive it today and it starts slowly falling. When I got back to the shop, I am only reading 12. 3 volts off the alternator that read 14+ the other day.



Does anybody have any kind of idea what may be going on? Is there a way to test the voltage regulators? Should I just order a new regulator? I traced as many wires as I could before seeing cross eyed and I don't see any freyed wires or anything.



Anybody's help is greatly appreciated.



Mitch

 

[tugboatphil]

Mitch,

I had a 90 D250 and replaced several voltage regulators. They are cheap (well, used to be around $12) enough to keep one or two new ones around. I used to carry one in the glove box.

They are notoriously undependable.

 

[DPellegrin]

My recommendation would be to get rid of the external voltage regulator and go with the integral type alternator, then you only have one wire-the output terminal. Since it appears that the Dodge voltage regulators are notoriously unreliable, you could get real crazy and wire in a Ford or Delco-Remy voltage regulator. There are only two types of voltage regulator: the type that grounds the alternator's field windings and the type that energizes the field windings. The regulator makes and breaks ground a few thousand times per second or energizes the field a few thousand times a second. Both Delco-Remy and Ford make them both ways. You just need to get a schematic and figure out how Dodge does it.

 

[mysteryman]

voltage regulators

"notoriously unreliable," I don't think so !!!!

We used that regulator from 1970 threw 1991. I have seen some of them go over 500 K on fleet vehicles... .



On the other hand... . the aftermarket regulators are not always all that good... They are NOT the same on the inside as the ones that you buy at your Dodge dealer !!!!



Another thing worth mentioning is that if you have an intermittent short in the field circuit or worse yet an intermittent short in the engine to body ground circuit... . You will blow regulators over and over again. .



This happens mostly in the northern states where they put salt on the roads in the winter!!!! Those *******s!



I say we declare it national open season on all salt spreaders . . LOL



In conclusion: The stock system will work fine if you use good parts and fix the wiring... My 72 W300 used the same regulator for the first 26 years of its

life. My 1980 Gran Fury x company car still has the original regulator on it today. The regulator out lasted the first engine!

My recommendation would be to get rid of the external voltage regulator and go with the integral type alternator, then you only have one wire-the output terminal. Since it appears that the Dodge voltage regulators are notoriously unreliable, you could get real crazy and wire in a Ford or Delco-Remy voltage regulator. There are only two types of voltage regulator: the type that grounds the alternator's field windings and the type that energizes the field windings. The regulator makes and breaks ground a few thousand times per second or energizes the field a few thousand times a second. Both Delco-Remy and Ford make them both ways. You just need to get a schematic and figure out how Dodge does it.

 

[tugboatphil]

Mysteryman

Which did you mean, that you didn't think the regulators were notoriously unreliable or that aftermarket ones are not always that good? I couldn't tell for your shouting. Isn't your answer a bit self-contradictory?

If the factory model was all that more rugged, I wouldn't have had to replace it the first time. After the 2nd one, I figured that cheaper price was the way to go. As to my original statement, I stand by it.

**In the interests of full disclosure, I am not now, nor ever was an employee of Chrysler Corporation or any of it's subsidiaries and owe no allegiance to them. Therefore my personal accounts of actual events and experiences should be considered uneducated at best and downright stupid at worst. I am merely an owner and driver of 2 Dodge Cummins diesel trucks. **

 

[JLEONARD]

Not sure if I would say "notorious unreliable" but they are noted for having a relatively short life.

I had 2 Dodge Darts (ok one was a Valiant) that had that regulator... both fried batteries in nanoseconds when the regulator failed.

(Knock on wood) I replaced the one on my truck when the alternator went out... . I figured I'd repalce them as a set.



I can't remember ever replaceing a regulator in anything else I have owned.



Jay

 

[cerberusiam]

I am getting 14+ volts from the alternator. Drive it for a couple of days with no change. Still get 14+ volts. I drive it today and it starts slowly falling. When I got back to the shop, I am only reading 12. 3 volts off the alternator that read 14+ the other day.

Mitch

That sounds about right. Your battery was fairly well discharged and it was taking 14 volts to charge it up when you started, After driving for a while the battery is now fully charged and the voltage regulator sees no reason to charge. As long as it maintains 12 to 12. 5 volts charge minimum you should be good.



To test, turn on the high amp draw accessories like lights, blower fan, etc, and check your voltage again. It should not drop below 12 volts at an idle and once you put some rpms in the engine you should see 14-14. 5 volts charge. If it is low at an idle and your idle is correct it could be a weak regulator, alternator, bad ground, bad wiring. I assume you load tested the battery and it checked good. If the battery is weak it can also affect the readings.



Like mysteryman says, the original is system is fairly reliable IF, and this is a big IF, your wiring and grounds are good. The charging system is absolutely dependent on all components working correctly with good connections. The older the trucks get this becomes an issue.



As for quality, the original parts sourced in the 70's were almost indestructible. However, the 80's spelled the end of quality even for the DC supplied parts. The dealer parts were, and still are, better but they are no where near the quality they used to be.



Just another symptom of cost vs quality and outsourcing that has become the norm.

 

[DPellegrin]

Far be it for me to make comment on the reliability of Chrysler electrical system components. I was mearly stating the obvious from the previous posters experience. Please notice the word "seems". This denotes a guess on my part. I still think it would be cool to "wire in" a Delco voltage regulator, some of the early ones were actually adjustable. BTW the open circuit voltage of a fully charged battery at 70F is 12. 6V

 

[PGunther]

I replaced the voltage regulator that failed the other day with another used one and it is back up and going. This morning I picked up a new one to keep on hand. I am not sure where you got one for 12 bucks as mine cost more than twice that!!



I was thinking of running a seperate ground wire from the regulator screws to a good clean ground somewhere else to remove the possiblity of it not grounding out correctly just from the screws in to the firewall.

 

[JLEONARD]

I was thinking of running a seperate ground wire from the regulator screws to a good clean ground somewhere else to remove the possiblity of it not grounding out correctly just from the screws in to the firewall

An excellent idea as you can never have too good of a ground. Ground both to the body and the engine while you're at it.

 

[NIsaacs]

I agree, the early Dodge Cummins powered pickups have lotsa problems with the regulators. Thats cuz they are from the 70's and can't handle the 120 amp alt. of the Cummins. (89-91)





"NICK"

 

[DPellegrin]

WOW!! Things from the 70's are considered inferior. I guess I'm in trouble I have brain damage from the 60's!!!

 

[PGunther]

I ran the extra ground and so far so good. I ran the truck for about 7 hours today pushing snow and so far so good. Thanks for everybody's input!!

 

[cerberusiam]

WOW!! Things from the 70's are considered inferior. I guess I'm in trouble I have brain damage from the 60's!!!

:-laf:-laf Now, THAT is funny!! :-laf:-laf

 

[Moab4x4]

Regulators

Glad it's up and charging!

I too keep a spare behind the seat or in the trunk of the Dodges that I have that use them. I have found out that if the regulator under the hood has the company of one in the trunk it never fails.

I like the mopar regulator best of the ones I have used. The old delcos were mechanical and I will take solid state any day for long term reliability. I personally like having the regulator not integral with the alternator. That way if a regulator goes bad I don't have to replace the whole alternator.



I agree completely with cerberusiam's post.



BTW I don't see the 120A alternator causing a problem as the current does not go through the regulator, it is in parallel with the battery so it never sees current. (that is if all the wiring and insulation is stock. )

Ken

 

[cerberusiam]

I have found out that if the regulator under the hood has the company of one in the trunk it never fails.

Ken

Funny how that works ain't it??



Its like they just get so lonely they just burn themselves out and DIE! :-laf:-laf

 

[DPellegrin]

Moab4X4- Delco Remy did make electronic/semiconductor type voltage regulators (not mechanical). They were typically found on Class 8 trucks in the late 70's. They were thermally compensating, grounded field and adjustable with a small "allen" wrench.



About this time Delco went away from that type of charging system to the integral type alternator in several different current output ratings. While your assessment has some merit with regard to your concerns about not having to replace the whole alternator should just the internal regular go bad, my preference would be to eliminate as many of the wiring problems that always crop up especially as the vehicle gets older. This is why I recommended the adaptation of a integral type alternator.

 

[PGunther]

Maybe I should just mount the spare on the fire wall right next to the other one. Atleast than it would know it is not alone. And it would make it pretty easy to switch over when one burns out as well.



The new one I picked up was from Napa, that is where we get most of our parts for the shop... plus the business discount is nice sometimes. It is an Echlin part. I hope I don't need it. . but one never knows.



Now I have to get the truck running again. The kid that works with us took it home and let it sit out in the 0 degree weather last night and I think it geled up. I pulled it back to the shop and I am defrosting it until tomorrow night. I also changed the fuel filter while I had it in there again.

 

[mysteryman]

I don't think I was contradictory at all.

The regulators that we built were very reliable !!! We have the service records to prove it

Many of the aftermarket regulators were often unreliable due to their various different internal designs. . Notice I said many and did not say all. .



If you are blowing regulators often and are using good regulators...

The problem is in your wiring or alt. . Or you are overloading or putting too much of a load on the system... It is just that simple...



Good luck...

Mysteryman



Which did you mean, that you didn't think the regulators were notoriously unreliable or that aftermarket ones are not always that good? I couldn't tell for your shouting. Isn't your answer a bit self-contradictory?



If the factory model was all that more rugged, I wouldn't have had to replace it the first time. After the 2nd one, I figured that cheaper price was the way to go. As to my original statement, I stand by it.



**In the interests of full disclosure, I am not now, nor ever was an employee of Chrysler Corporation or any of it's subsidiaries and owe no allegiance to them. Therefore my personal accounts of actual events and experiences should be considered uneducated at best and downright stupid at worst. I am merely an owner and driver of 2 Dodge Cummins diesel trucks. **

 

[tugboatphil]

The problem is in your wiring or alt. . Or you are overloading or putting too much of a load on the system... It is just that simple...

Well that pretty much settles the issue. It is not possible at all that some voltage regulators are made with substandard materials or not within design specs.