Need Help! Battery Charging/Alternator problem

[guava]

93 w250=



During my travels, My battery blew itself up by overheating. It only blew the cap off half the batter and I was able to continue driving for 200 miles but I was afraid to shut it off for fear of having no power to start. I pulled into a little town and the battery/voltage gauge dropped to nothing and in about 10 seconds, the truck died. Luckily, I was next to a farm store and buying a battery got me up and running for the last 76 miles. I got parked and took a look at the battery and sure enough, it was pretty warm.



While I haven't tested the alternator yet, I feel its probably sending out too much voltage to the battery. If I recall correctly, the voltage regulator is controlled or incorporated into the computer.....



Someone help me by guiding me to the solution or suggest the proper way to diagnose this. I've got about two days to fix this or I've got to buy a plane ticket and get home.....

 

[WJune]

Seems like I heard that some of these chain auto parts will test or diagnose for free ?

If not, they may recommend someone who knows what they are doing. Good luck.

 

[pepecat]

happened to me too. the truck smelled real bad!!! like sulfer! My father asked if I got a dose of High sulfer Diesel fuel??? But no it was the battery's Sulfuric acid! Replaced the voltage regulator, still charging at 19+V replaced the alternator to the tune of almost 200 clams and the prob was fixed. Now my engine compartment is acid stained.

 

[IRoss]

Having been down this road this summer, the advice I give to you is to ground the voltage regulator REALLY well, as in running an actual wire from the mounting bolt on the regulator straight to a battery ground. . it doesn't hurt to shine up the body grounds there as well... . i went through 3 voltage regulators, changed my alternator and replaced both my batteries before a dodge mechanic told me that the body grounds in this instance are commonly inadequate. Since running this ground I've had no more shaky needle syndrome, and my gauge shows 15 all the time. .

 

[guava]

Having been down this road this summer, the advice I give to you is to ground the voltage regulator REALLY well, as in running an actual wire from the mounting bolt on the regulator straight to a battery ground. . it doesn't hurt to shine up the body grounds there as well... . i went through 3 voltage regulators, changed my alternator and replaced both my batteries before a dodge mechanic told me that the body grounds in this instance are commonly inadequate. Since running this ground I've had no more shaky needle syndrome, and my gauge shows 15 all the time. .

OK, dumb question, which one is the voltage regulator and how do I find it?



does anyone know how to bypass the computer to use just a normal voltage regulator?????

 

[cerberusiam]

OK, dumb question, which one is the voltage regulator and how do I find it?



does anyone know how to bypass the computer to use just a normal voltage regulator?????

Voltage regulator is built in to the PCM. Check your battery cables real well and make sure they are good. Pay close attention to the power wires off the positive cable end and make sure they are in good shape. They can corrode inside and sap the charge into the battery causing over charge.



Have you checked the charging to make sure it is not over charging?

 

[guava]

Both the battery cables are new within the last 6 months. The secondary power leads from the positive are not new and I'll take a look at those tomorrow.



Its been suggested there is a way to bypass the regulator in the ecm but I haven't gotten a response on how yet. I'm sure its a case of over charging but I've not come up with the cause.



I'll be digging into all the grounds and make sure nothing is sapping it but I'm not real hopeful.

 

[Jgolden]

Did you check the alt output with a multimeter?

Also, an intermittent short or dragging (for example) fan motor can mess with a battery.

Don't know about your year, but on my 98 ram the PCM is pretty protective of the electrical system,and the alternator,(learned that after using the two screw driver circuit test) and expensive if you shock it.

 

[IRoss]

I was assuming that this is your 93 you were talking about, in which case the VR is mounted on the back firewall above the rear of the engine... . it will have a 2-prong plug into it... . I beleive it has two mounting bolts... they're cheap... .

 

[Philip]

The 93 has the voltage regulator built into the PCM. There is no external unless someone installed it.



Have you had the alt tested yet?

 

[guava]

I had the alternator test while it was out of the truck. It tested good. They did the test several times without a change in the results. Don't know how reliable it is and the local cummins shop was't offering to help me out. I'm going to put it back in and then take it to the shop for the quickie autozone charging system test. From there I'm going to run down to the auto electric shop and see if they can get some type of regulator working outside of the PCM.



Why can't I just drive a truck from the stone age and enjoy it? I'm getting closer to just starting it and pulling the alternator out of the equation so I can finish my trip and get home.

 

[MMeier]

g, where are you stuck at? sounds to me like you are going to need a new PCM. I did get my "new" W 250 last month BTW

 

[guava]

g, where are you stuck at? sounds to me like you are going to need a new PCM. I did get my "new" W 250 last month BTW

I'm stuck in Seattle. Trying to get back to Boise. I'm in the wrong city with the wrong truck. I was down your way recently for the big bike party. Was a fast trip, otherwise I would have looked ya up.



I'm working to cut out the pcm, not replace it. If I thought I could start it like a lawnmower, I'd take the whole damn battery out.

 

[WJune]

I have heard in some cases running without a battery to charge ruins the alternator ?

Just to get you home, perhaps by a 2nd cheap battery an swap them every 100 or so miles, whatever you feel comfortable with. Maybe run lights etc to ease the load on battery. Batteries are cheaper than these alternators.

 

[Moab4x4]

Hey Guava, Hope you got home. Quick and dirty way to get home if alternator is good, but overcharging the battery is this: There are two field posts on the alternator. The PCM on the 92-93 trucks controls the voltage across the field. Unhook the original wiring harness. Ground one post. Connect the other post to 12V and you get full charge. Unhook it and you have no charge. I made a trip home once hooking the post up whenever my voltage guage showed 11V or so and unhooking it after a while. I stopped from time to time and if the battery was warm, I unhooked my "charge" wire. The truck will run down to 7V or so keeping the fuel solenoid open.



The option you were looking for is to install the old standard Mopar voltage regulator. I just wired it like my 72 Dodge manual said to. One wire went to that field post and the other went to 12V? (been a while since I did mine) Case had to be well grounded. I installed mine on the passenger fender, but on the firewall would have been a little better protected.