Hey guys, a couple of weeks ago I noticed the smell of battery acid and the battery seemed to be overcharging so I made the mistake of buying a new ecm, thinking that was the problem, I let the truck sit for a few days and when I went to start the truck it was stone dead jumped the battery and it ran, then I tested the battery and it was no good so I purchased a new battery and checked all my fusible links plus I cleaned the battery terminals.
I started it up and put my meter on the alt and it was putting out 13.93 and then I put the meter on the battery and it was at 13.89.
What do you guys think? maybee the last step would be the alt?

 

Sounds a little low, but still servicable. I wish I had only 13.9 volts going through my system.

 

That is only 0.09 volts drop in the charging wire from the alternator to the battery That is acceptable, remember the wire is only 6-gauge and they are trying to push 120-amps through it.

13.89 volts at your battery should keep it charged, if the battery was overcharging it could of had a shorted cell, the alternator would try to charge a now 10-volt battery and cause it to boil the electrolyte.

Overcharging can also be caused from loose grounds; usually an alternator will only produce the amount of current that it is told to through exciting the field windings through either the ECM or the voltage regulator.
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So what is the problem you are having now, is the battery still staying charged?

You could pull your alternator and have it bench tested at Auto Zone.
Jim

 

I think it was just a bad battery the whole time.

 

I think you are right.