Thread: Swapped battery, now starting issues.

Newbie here! I registered because I recently bought an 07 Grand Prix (V6 non-charged) and I know this forum can be a benefit. I don't know if I should post this question here, but I have a major issue. Two days ago I swapped the battery on my car becasue it was giving me issues starting in the mornings. Since it was late Sunday and my nearest Auto Zone was closed I decided to swap the battery from another car that is just sitting in my garage. I noticed the battery was larger and had more crancking than the original so I kinda rigged it by finding a new ground for it. Car started up and drove around with no problems. Well today the car suddenly died on me at a light without any warning. No power whatsoever. I messed with the battery cables which were a bit lose and coroded and heard power come on. The car started like nothing for a few seconds and died again without any power. Someone offered jumpercables but nothing. My question is, can this be my alternator issue? Doesn't the problem start with interior lights or headlights fading first? It's got to be electrical in my mind. I'm about to clean and retighten the posts. I will also check to see if the new ground is adequate or if any lose cables got crimped. If anyone has had this happen before please help. Sorry for the long post.
Thanks in advance!!

Well, let me just start by saying I agree with Matt.

Here is what I would do, first get yourself a new group 34 battery. Not some POS you have sitting around. I’d aim for a CCA of 600-700, any more is totally a waste unless your running huge amps/subs or something. You can save a few bucks and just get a normal flooded battery if you’re strapped for cash, the AGM battery’s are nice but you pay for them.

Now for the grounds, the factory grounds are adequate if they are clean and tight. If you routed a new ground cable I’d bet a twenty spot you bypasses the amp meter. Doing this will mess up the charging system, that amp meter keeps track of the battery state of charge. And when you bypass the amp meter you will have issues eventually.

Now that wiring job and old battery you put in there may have messed up the alternator as well. You shouldn’t put a discharged battery in a car, even if it is charged enough to start it. Recharging a deeply discharged battery is very hard on any cars alternator.

In short, replace the battery and return the wires to stock configuration. Then go from there.