Alternator not charging?

[slick]

So I've read the post about charging problems, but I'm still unable to figure out my problem. About a week ago driving to work with the lights on for the first time my truck started to crap out at about 2500 RPM. I pulled over and everything seemed to be fine. I started back out and before each shift it would start to miss bad. I fugured it to be the alternator going out causing the electronic ignition to not have enough juice. That's also when I realized the amp guage on the discharge side a little. I bought a new alternator and even had it tested and it's good. I've tried 3 different regulators including the blue Mopar one and another new one. When I pull the battery cable of it dies. Fuse is good. Drove it all week and it starts every time and runs great, even passed emissions today. Any ideas?

[Rusty_Quarters]

I'm not the most experienced but I know that sometimes (on dodge cars anyways) the gauge on the dash will go bad and it will still move some, but it won't work properly, and you can jumper or bypass it and that will fix the problem, you might check on Moparts website, I remember reading about having this problem quite a bit on cars, these guys here probably know more about it than I do, but, I have heard of this being a big problem before on Mopars.

[slick]

I was driving to the dump today and BAM the alternator started charging Don't know what the deal is, but as long as it keeps charging I'm cool with that!

[reallylongnickname]

I've got a similar Q. about charging. If the vehicle is running and u disconnect the battery cable, it should still keep running right? If it stalls, it means the alt is not charging. Am I right? w300 will stall if I disconnect the cable pos or neg. I took the Leece Neville alt off and had it tested. It is working fine.

[slick]

if the alternator is bad it will die..

[reallylongnickname]

That doesn't tell me anything though. There are other issues I have that can cause it to "die".

Does disconnecting the battery cable cause it to stall?

[MountainMoparRobin]

sounds like a connection has gone bad, yes if you disconect the pos and it stops that means alt isn't running the circuit, ie after motor is running the alternator supplies electricity to run the vehicle and recharges the battery, which means the alt could be good but, the circuit to run the vehicle from the alternator has something wrong trace the wires and connections and I'll bet you'll find something simple, Mopars charging systems have always been one of the best

[dodgegrrrrrrl]

A bad ground can cause that problem as can a bad regulator. The alt will test good but it still won't charge when in the vehicle
A corroded battery cable or connection to the post can do that also. It may look fine but not have continuity because of corrosion you can't see.
A dead or shorted cell in the battery or just worn out battery will also cause this as the alt. will only charge to the battery's voltage and ampacity.
Worn our alt. brushes can too, as they skip on the armature they will charge intermittently.


If you DC the battery with the engine running and the alt. is working the voltage can spike as high as 24-28 volts which makes short work of electricals and electronic ignitions, regulators, etc. I popped both headlights like a flashbulb doing just exactly that the other day. The old mechanical regulators wouldn't do that. I have taken my battery out of my scout and loaned it to somebody who was dead in the road and just kept the scout running til we got their dead meat off the road. The new electronic regulators won't hold the voltage like that though so as the field goes unregulated by the battery exciting things can happen. Good thing I had spare headlight bulbs.

[powerwagoncrazy]

Keep an eye on your firewall plugs- they can get corroded or the pin can break off, causing no charging or worst case a high resistence connection (ie wiring gets hot and you might experience an electrical fire...). Best to just eliminate that connection and run a solid wire through the firewall...

[MountainMoparRobin]

powerwagoncrazy
hit on a good point, thier is a main line at the fuse box, its the largest wire and it leads directly to the gauge, anyway I periodically have to clean that connection, it carries alot of voltage, its direct to the altenator then to gauge then to regulator, the fact slick that you all of a sudden seen the charge, could be the fact that their is corrosion thier, if you have the plastic plug on the fire wall its harder to clean, I cleared out this area years ago and put on another connection and left it open for easy access, it can be the culprit

[RussRoth]

You fellers that have trouble with electrical connections might try using di-electric grease on your connections after you clean them. Since I started using it my troubles have been nearly eliminated. I have a set of low voltage lights along my driveway (11 of them) that the previous owner had a lot of trouble with and I did too until I cleaned all the connections and used the grease. In the last 8 years they have not quit even once. All I have had to do is replace a couple of bulbs. And a light or two that someone backed over. I try to use the stuff any time I do any auto electrics. So far has eliminated the TC lock-up hunt on my '01 for a couple of years now. I used to have to fix that about every 3-4 months.

[MountainMoparRobin]

Good point Russ and for some reason I keep forgetting to buy it????????????