judgester

Today I installed two new batteries and I noticed something was not right, the volt meter did not go above 10-12 on my drive to work, normally would run around 14+, also noticed my air dog was louder than normal. Got to work looked under the hood and the passenger battery blew up, acid all over the engine bay. Went and got a new battery and seems to be having the same symptoms, I unhooked the pass. side bat. and it runs just fine, airdog is quiet and volt meter is at 14+. What would be causing this, the alternator is getting hot when both batteries are hooked up, and yes I have positve and neg correct. Did not find any shorts or anything, what would suddenly be causing this as all I did is swap batteries? Thanks.

J BODY

clean clean clean your cable ends. Pay particular attention to where the cross cable attaches at the left battery.

Sur5er

Sounds like you're running the batteries in series or have the connections screwed up. Double check your wiring.

Totallyrad

Unhook the batteries and check out the one that seems to be OK. You could have gotten a bad one, possibly has a dead cell. It happens.

judgester

I am not sure what the problem is going to be, I thought it was a bad battery but after replacing the old one the new one is doing the exact same thing so I disconected it and its running fine. There has to be an issue with something else. Its like there is a short/resistance someplace, I need to check the cables again I guess, someone mentioned the ECM possibly? It has something to do with the passenger side battery as it works fine when it is not hooked up.

1-2-3

Do you have two different batteries? one with the P and N posts reversed? That'll make you hook them in series if you hook them up the same way.

patdaly

J-Body gave you your best clue, also do a search, I remember this from times past, if I remember correctly it was a corrosion problem somewhere in the cables..

judgester

Possibly just possibly found the issue here. I hooked up the Smarty to see if there were any codes, found P2509 code and cleared it out and hooked up the other battery and it seems to be back to normal, not sure if I trust that was the issue but seems to be charging normal, airdog is normal sounding, and terminals are not hot. The old batteries did die trying to start the truck, thats why I replaced them. Could this code actually have been my problem, code says ECM/PCM Power Signal Intermittent.

1-2-3

having a code won't make a battery pop.

judgester

Ya I am a little skeptical that was the issue. Having this code could it possibly have been affecting how the ecm/alternator are working. Like by clearing the code does that actually fix anything or is the code just there to tell you there has recently been an issue with something.

J BODY

Unfortunately the charging system is a big circle on the DR trucks as opposed to the superior design of the BR/BE platform...........but we'll touch on that another time. We'll start at the alt. There you will find a large wire that goes directly to the right batt. You'll then follow the cross cable over to the left (drivers) batt where it connects to the B+. From the B+ the cables go to the ECM eventually. Here's what happens, or what I've experienced more than a few times. Corrosion or poor connection. I've seen it at either battery, but more so at the left battery where the cross cable is bolted up. The ECM monitors battery voltage and if it falls below a certain threshold will full field the alternator to increase the charge. That creates a prob if the voltage drop is excessive from the alt all the way over to the ECM where B+ is monitored. The ecm will see a low voltage and bring the charging level up..... unfortunately this can hit the right battery with up to 16 volts. If anybody wants to play around with this grab your DVOM, unhook the cross cable at the left battery and start your truck up (safety glasses/face sheild highly recommended). You'll find excessive charging voltage at the right battery, but only stable battery voltage at the left. The ECM will only see the voltage of the left battery and ramp up the charging. If for some reason you're boiling batterys and the voltage is high at both batterys, you'll need to find where the high resistance is on the 12v feeds to the ecm.

Jeff in TD

^ Excellent explanation.

AlpineRAM

I would suggest that you get some baking soda, dilute it in water and wash your engine bay and all the places where the acid could possibly have gone-dripped etc.
Baking soda will neutralize the acid, and will spare you a lot of headaches with corroded cables, eaten hoses etc.

Just my 2c

AlpineRAM

papaduck

I agree with AlpineRAM that you shoud wash down the engine bay. Baking soda would be good to wash down the interier of the engine bay but I think that vinegar would be better. Vinegar can be washed off much easier and will not leave a powder mess and also vinegar will help to prevent rust. A trick that a body man taught me when I was stripping a car to be repainted.

judgester

Thanks for all the imput, I will check for corrosion again and clean the gounds up a little more. Still not sure if that P2509 code was effecting the ecm/alternator but after clearing it out the truck has been fine for 60+ start and stop miles. I did do the baking soda and water thing but it did leave a huge mess, the bad thing is acid sprayed on the fender and ate the paint right down to the metal. Gotta get that fixed for sure.