Issues after battery died on 2013 LS3

[jethrobandit]

Thanks all for the info. So far, I'm nailing it on the Forza and am sending an email to see if he has any thoughts.

I got the battery tested and was anticipating getting a new one, but Autozone tester said it was in good shape!!?? So, I took it to O'reilly and they said the same thing. All the while, it's been driving and sounding just fine today. I'd left it on a trickle charge for 36 hours since my issues yesterday.

So, a little background, I've had this Forza controller on the car for almost 3 months now. I had the headers, cam, and tune done 8 weeks ago. Up until yesterday, everything has been fine. I just haven't been real happy with the tune. But, battery, et al have been operating normally. No slow cranks or anything. I've actually left it for a weekend without driving it on a couple of occasions without issue. So, just not starting it for 2 days shouldn't create a drain issue out of the ordinary.

However, the Forza is dead now. Won't turn on. I've pulled it from the fuze box and replaced. Pulled the ground and replaced and checked all the wire connections. So, it must have gone fritz and tried to take the battery with it??!!

[christianchevell]

My Forza could drain slowly, eventually the light went out but it worked, I disconnected it. Your just needing a new battery and a reset by completely unplugging the battery. Your going into limp mode like my car will if it cranks over way too slow form header heat stroke. Just unplug the battery and it should clear all the codes on restart with a good battery, batteries only live 1/2 their life with good CCA usually. Pull the fuse F the noise..LOL its music...... Make sure the lousy ground in the trunk is sanded down as its the crappiest ground of any vehicle I have ever owned and that's a lot.... its like a friggin 1/4 20 bolt though a threaded flat bar spot welded to the trunk and painted WTF were they thinking...and it holds down a harness also..... And check all engine grounds on the engine and the connections of all electrical when someone else has worked on your car I found my Fuel injector grounds loose from a real good pro... constant interuptions due to popularity lead to mistakes. BTW most auto parts store don't load test with their testers they are cheap...............

[bd2014rs/ss]

Mine went dead once after setting for a couple of weeks. Upon jumping it off another vehicles all my lights were flashing as well. And it was missing and backfiriing. I assume it still didnt have enough juice to control the ecm. Put my trickle charger on it. Fired it up later no problems. 10k miles ago. So i wouldnt be concerned on the miss problem. But i would have the battery checked. Harbour freight sells cheap load testers. They work actually pretty great.

[camarosspower]

Did they test just the battery or did they test the battery on the car and from the engine department? I had that happen to me. Battery tested good but when they tested it from the engine department it failed. Just something to think about

[Soybeanrice]

Originally Posted by Olddudesrule

RJ is right. Get an OBDII code reader, a manual, and I would add a voltmeter. Low voltage issues in modern cars can cause a number of seemingly unrelated issues. Coupled with the fact you have a non-OEM tune, and who knows at this point. Start with the simple stuff like what is your resting battery voltage. If it's below 12.2-12.3 (yes, even that low), have it tested under load and get rid of it if it's failing. Once you know you have a functional battery, check connections, specifically grounds and plug wires. Troubleshooting, even for a novice like me, is all about having a checklist of sorts and starting with the simple solutions first. Then I would have the tune checked by a professional. Don't chase parts......

This. Especially with your weird symptoms. Easiest one to check is on the front left (looking into engine bay) on the head.