SOS - Battery Disconnected - Low Idle, Stalling, Will not maintain Startup

Alright so this is my first call for help. Usually I can find the answer to any issues I run into on here, but it looks like my luck finally ran out. I've read others experiencing issues after disconnecting their battery, but most seem to be 1st Gens and there are dozens of restart procedures, "hacks", etc that get them on their way, but I had no luck w/ any. Apologies for the length.

I drive a 2013 5.7 CM with about 132,000 miles on her. I purchased this truck off of my dad after school a few years back and he is certain that it's still the factory battery in there (which blows my mind). Regardless if that's true, it's definitely due for a replacement in the near future. Neither of us have ever experienced these issues with this truck, but then again neither of us have every disconnected the battery.

I installed a new 40" RC light bar tonight (build thread was supposed to begin tonight but then this happened lol). Disconnected only the negative terminal, bc I was seeing tiny sparks when messing with the positive side and thought I'd avoid a surprise. Got the light wired to both terminals, and ended up mounting the resistor to the existing ground mounts for the wires coming from (I think) the fuse box on the right side of the battery. Light bar worked - and dang is it amazing, so I had to take a 5 minute drive to the darkest road in the area.

Starting the truck, I immediately noticed that the truck just sounded quieter. Headlights didnt loose any brightness either. Regular sounding startup, but would get very quiet almost like an electric car. Checked out the forum and saw many people talking about the ECU loosing its memory and it would take 20-100 miles for the truck to relearn the different driving parameters. I took it out anyways and on the way there, went to make the turn onto the road I was going to test, and as I flipped on the turning signal, suddenly all of the dash lights came on, I lost my powered steering, tires were slipping and off sync and nearly drove straight off the road into a creek lol.

Half on-half off the road, I couldn't get it to hold a start. It was a very weak sounding start, and if I either went to either turn the headlights on or off, take my foot off the brake, and do pretty much anything else the truck would turn back off. Throwing it into gear would make it jump a little then it would die again. Was finally able to get it started by having the lights on already, starting it while in neutral, and letting it run for a minute or two. Got half way home and the same thing happened. Had a very difficult time trying to get the truck to hold a start. Read about the throttle body sensor condition and restart, and tried every technique I could find - still no luck. I began to think it was because I mounted the resistor to those screws, so I took it off and just let it hang (seen below). The truck was able to start back up, but with the 4HI, Traction Control, & Check Engine Lights on and I managed to get it home.

I'm at a loss here and need the gang's opinion on how I should go about fixing this. Planning on looking up how and try and clean up the Throttle Body Sensor tomorrow. A new battery is on the list this month for sure, but am I going to see this same problem happen again when I get the new one? Should I just try to get it to AutoZone/Advanced to just get the replacement tomorrow and see if they've ever heard of it? Any input will be greatly appreciated!

 

There is quite a bit of corrosion on those battery terminals. I'd start with cleaning those and see what happens.

 

All of this. Those terminals are likely the problem, what you're describing is what happens during low voltage situations.

Get a terminal brush and clean them until they're shiny metal.

 

I think it’s time for a new battery

 

I agree with all 3 of you, and thanks for the insight!
I’ve cleaned off the existing battery and terminals a couple of times in the past, but a new battery is definitely on this weekends agenda. I’m going to look at some new terminals too.

 

Update: decided to drive the truck into work today to see if it would stall out again. Started up and sounded normally, but was showing the check engine and traction control lights, with the 4LO light blinking. It drove fine for the 6 miles to work.

I wanted to stop down at Advanced and autozone by the office to see what kind of batteries they had and if they ever heard of this issue.

As I left to head their way at lunch I noticed I had no lights at all and the truck was running completely normal. I mentioned the issue to both anyways (Neither had any ideas). Drove it back and then home later on and still no lights.

Definitely still getting a new battery and terminals. But thought it was weird how well it’s running now and wanted to share

 

The reason it is not idling is that the throttle body is gunked up due to high mileage. Once the battery is disconnected, the ECU looses the idle throttle position setting and it will not idle properly until it relearns. To fix the problem, take off the intake hose, soak a rag with brake cleaner or throttle body cleaner, prop the throttle plate open with your hand and wipe inside the bore real good. Wipe the edges of the throttle plate as well.

 

Awesome, thanks for the info man! Actually picked up a bottle of throttle body cleaner today and made sure it was safe for the O2 sensors. Was about to YouTube how to clean it and get to work when I saw your response.

 

This may sound silly, but what is the condition of the serpentine belt?

 

Hmm didn’t think about that but I’m not sure. It has a slight squeak to it sometimes on a cold start but haven’t taken a close look at it in a while. The squeak doesn’t last more than 20-30 seconds but I haven’t looked up any threads on that. Could the belt be throwing something off? What’re you thinking?

 

Endagon might be thinking loose/old belt on the alternator?

 

The truck has hydraulic power steering, not electric. When it fails, plus symptoms in other systems of low voltage, and the engine getting too quiet like it's missing a fan roar, I'd be looking to see if the belt is still in the truck because the one belt drives all of that.

Don't drive without it because it spins the water pump too