Hey folks, 

It seems I’ve gotten myself into a situation. About 2 weeks ago my alternator started going out. It would charge fine for a while then drop voltage to 12.3-12.4 and sometimes completely off to around 11v. Monitoring with the gauge on my edge. When charging it would bounce from 13-14v. This started when I was about 300 miles from home. I limped the truck home without replacing it and noticed that on the back of the alternator the clip which secured the plug had broken and would not click and secure. Figured this was my problem and engineered a zip tie fix but didn’t drive the truck again until yesterday. On that drive the truck started giving me the 30 second dead pedal every mile or so and throwing a bunch of codes. No surging, coughing, breaking up, just dead pedal. A couple glow plug/heater grid faults which were present before, a companion module fault, and everyone’s favorite: P0216. I replaced the alternator and cleared the codes today hoping I didn’t procrastinate for too long. Well, my voltages are nice and steady but it gave me dead pedal 500 feet from my house so I assume I’ve fried either the Vp,ecm, or pcm because I didn’t immediately replace the alternator. I don’t trust driving it long enough for the codes to come back but I could if necessary. My VP only has 39k on it and has had 15-17psi from a FASS the whole time. Alternator is just a duralast but I did have them test it before I took it and it checked good twice. I should also note while unsure of its relation to this issue that my truck has a particular talent for corroding terminals heavily and often. Where do I start with this? 

As always, thank you guys for being the most helpful cummins forum out there.  

There are several things to address here - I would start with the basics first.  

 

The corrosion you mention should not be happening.  How old are your batteries.  Corrosion at the terminals usually means that the batteries are venting excessively.  Have you done the recommended WT-ground wiring modification?  You will need to check / clean / tighten all of the cable connections, including the condition of the crossover cable.  

 

There is a battery temperature sensor under the driver side battery.  This sensor provides information to the PCM so maximum voltage will be regulated in accordance with ambient temperature.   Example:  95° - probably around 13.7 volts,  40° - probably around 14.2 volts.

 

You will need to drive the truck again to see what codes are showing.  When the alternator failed, random codes may have been set while the electrical system was operating at low voltage.  You need to see what is real.

 

- John

 

 

Thanks for the reply @Tractorman,

My truck does not have the ground mod done yet, I’m going to go ahead and do that and take the truck up and down the back roads near my house until codes show up again and report back with what it’s giving me.

 

Edit: The batteries were replaced the week before I bought the truck so that would be Late December 2019.

I had a lot of corrosion issues till I replaced the batteries and I also replaced the cables/terminals with a set from Geno's.  Now my terminals are as clean today as the day installed the batteries/cables.  They are a bit pricey and I'm sure you can make them cheaper yourself but I paid for the easy route. 

https://www.genosgarage.com/product/dodge-ram-cummins-replacement-heavy-duty-battery-cable-kit-ddg25kit/battery-cable-and-components

Both my work truck and the rv truck get a couple drops of oil each year on the battery posts and cable lugs. It keeps them nice. MoparMan told us about this trick a few years back. I still brighten up the posts and clamps ea year too.

On 9/17/2022 at 9:16 PM, Reaper22 said:

my truck has a particular talent for corroding terminals heavily and often

I had this happening on only one battery. Eventually realized there must be a leak between the lead post and the plastic battery casing. That allowed the nasty gases to do their thing.

Now I'm beyond careful when removing terminals from the posts!

First let me ask a few dumb questions...

 

Q: What are the only two materials that sulfuric acid can be contained in?

 

1. Glass

2. Plastic

 

Q: What is plastic made from?

 

1. Oil

 

So if you keep the terminals wet with just engine oil the corrosion will never happen. To this day I still have my factory battery terminals and they are still in super good condition. I've never had to clean them (wire brush or chemical cleaners). Engine oil will leave just a thin oily film that battery acid will not eat through. It doesn't get on your clothes like the red spray coating that stain. Not like grease that you end up getting on your clothes too. 

Only thing I'll add for the oil hack (which works incredibly well) is to check the top of your battery every once in a while. The oil will spread incredibly far and cover the top of the battery. Don't know if it could make a difference, but if the top of the battery gets a film of oil from post to post, could it cause a problem?

I've put one drop of oil on each post and rubbed it around with my finger. Then a week or so later, I noticed an oil film spreading over the top of the battery and wiped it off. Don't know if it could cause any problems or not, but I wiped it clean just in case.

 

 

And I'll add that all my vehicles remain corrosion free.....for the first time in my life.

3 minutes ago, Max Tune said:

The oil will spread incredibly far and cover the top of the battery. Don't know if it could make a difference, but if the top of the battery gets a film of oil from post to post, could it cause a problem?

 

Nope. Never happened with me... I do wash off the batteries with a power washer and then reapply after the washing.

5 minutes ago, Mopar1973Man said:

 

Nope. Never happened with me... I do wash off the batteries with a power washer and then reapply after the washing.

No offense, but alot of things happen to others that you seem to be immune to 😂😂😂

 

Not saying you're wrong....just saying 

11 minutes ago, Max Tune said:

No offense, but alot of things happen to others that you seem to be immune to 😂😂😂

 

 Really? Hmmm... 451k miles later still going. The only battery issue I had was the old starter was having issues and acted like the batteries were dead but after installing the new rebuilt starter, which was my factory OEM starter it started once quick and strong, then the solenoid plunger stuck and wouldn't let go. I have to remove and free the solenoid plunger and been working since. No it didn't arc and stick but wedged the plunger pin inside. Here very soon with winter coming Beast will be my daily driver. It has to be top notch and operating perfectly. 

 

Both batteries as they are right now. Dirty as well. Looks like power washing and oiling needed just a small spot of oxidation.

When there's oil across the top it collects dirt and I have been able to detect a very mild amount of voltage drain in the dirt so I try to clean mine often.

4 hours ago, JAG1 said:

When there's oil across the top it collects dirt

 

Worthy of mentioning.  Dirt usually has a lot of conductive particles is in it and can cause a parasitic drain, especially if it is damp.  So, keeping the battery top clean is a good plan.

 

- John

Mike mentions how his factory battery cables are still like new. I am certain it is from a small amount of the added oil wicking up into the copper braid. My cables are still good also, thanks to Migel Mopie Man.

What @Mopar1973Mandoesn't tell you is that he has a permanent elaborate engine oil feed drip system installed over each battery terminal.  I saw it by accident in one of his videos.  He doesn't want anyone to know how focused he is on battery cables. 

 

Filtered oil is the secret ingredient.

 

- John

I thought everybody knew to oil the battery terminals. Ralph McBride taught me at 12 yrs old, back in metal oil can days, when changing or adding engine oil drip the cans on the terminals!  And on that hood latch & hinges. 
Now back to the alternator, please. 

1 hour ago, DeepEastTexas2Gen said:

I thought everybody knew to oil the battery terminals. Ralph McBride taught me at 12 yrs old, back in metal oil can days, when changing or adding engine oil drip the cans on the terminals!  And on that hood latch & hinges. 
Now back to the alternator, please. 

Okay, Sorry about that... I would like to know some ways that cause diodes to start burning out. I am assuming when one goes the others left have to work harder and get hotter. 

 

Also some reasons why an alternator can suddenly short out .

Ok the best I can say alternator wise have your alternator bench tested. If it doesn't pass then its time to replace. Now as for the voltage regulator its inside the PCM. You need to pull the field lead and start the truck. The blue lead should show +12V and then the green should show -12V (or ground). This should only be present when the PCM sees tach signal from the ECM. 

 

If there is still charging issues then your going to need to send the PCM to a rebuilder like @Auto Computer Specialist have them test and repair your PCM. 

 

I've also got to ask did you do a W-T ground wire mod yet? If not I highly suggest you get this done very soon. 

 

 

All so install a fuse in the blue lead between the PCM and the alternator. 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/alternator-and-pcm-protection-r617/

4 hours ago, Mopar1973Man said:

Ok the best I can say alternator wise have your alternator bench tested. If it doesn't pass then its time to replace. Now as for the voltage regulator its inside the PCM. You need to pull the field lead and start the truck. The blue lead should show +12V and then the green should show -12V (or ground). This should only be present when the PCM sees tach signal from the ECM. 

 

If there is still charging issues then your going to need to send the PCM to a rebuilder like @Auto Computer Specialist have them test and repair your PCM. 

 

I've also got to ask did you do a W-T ground wire mod yet? If not I highly suggest you get this done very soon. 

 

 

Almost done with the W-T ground mod now, got interrupted by rain on Sunday but should have time to finish today. I replaced the alternator and the truck is charging normally now and isn’t draining battery over a few days, however the dead pedal hasn’t gone away. What is the likelihood that something like this fried my VP? I replaced it once already and I’d much, much rather send my PCM for a couple hundred than do the $1200 VP again. 

If it's charging good now the PCM is likely good. Dead pedal is communications  issues between ECM on the motor and VP. Electrical noise from various sources corrupt the signals or faults in either module cause com loss. Tuners tap into the bus too so unplug any and check the three pin bus connector by the PS pump for damage or frayed wires. WT mod reduces noise.