Dead battery; starts up in limp mode
 

Excuse me if I'm misinformed on what "limp mode" is exactly. I've seen it used, but never seen an exact definition of what it is.

This morning, my BRZ battery was to low to start the car after several days of sitting. The auto headlights were set to on, so the headlights were on when I got out of the car and opened up my other car's hood to jump. As I approached with the jumper cables, the driver's side headlight went out, but the passenger side stayed on. I hooked up the jumper cables, and the other light came back on. I jumped the BRZ, let it idle while I put away the cables, and then I backed out of the garage, noticing the idle was VERY rough. As I got out onto the street, I was really noticing the throttle response was terrible, and the idle was really bad. As I got going, it almost stalled, and as soon as the rpm's got up to about 2,300, it started bouncing like it was hitting a rev limiter. I pulled back around and went into my garage, thinking something major was wrong. I decided to kill it and re-start, thinking maybe the computer got screwy with the loss of power. It started up fine, and I drove it to work. Since then, it's been fine for three more startups and short drives. Is it normal for the computer to get screwy from a loss of power? I called my dealer, and they said it sounded plausible, but didn't say they'd ever had anyone else have this happen. Also, is what I experienced the limp mode?

Wouldn't surprise me if it took a little while for the alternator to charge your battery enough to get a solid voltage for some of your sensors which could cause the car to drive poorly. My advice is get a battery tender or figure out why your battery is going dead after "several days" of sitting.

Ok, now I know something is weird. I just went outside to roll my windows up, which were cracked to reduce heat. Five minutes later, I looked out, and my driver's side window was halfway down...

Get a battery charger and let it sit and re-charge before you jump to conclusions. Its possible the battery is also toast.

Sorry for necro this thread. Did it happened again!
The exact same thing happenned to me yesterday. It's -22 since couple day and didn't took the car for a complete day. Car didn't start and my neighbor used his battery pack and it didn't start either. We used cables and it started but very rough like a tractor and wanted to stall if i give it some gas and was unable to go past 2200 rpm exactly like you said. It was also boucing from 700 to 1000 every 5 sec when idleing. Let the car warm up but it was still bugged. It was ok when I restarted.

Well now, at those temperatures, all kinds of weird stuff can happen to an automobile.

It was most likely suffering from the cold, then the ECU thawed out.

I would suggest you invest in a battery tender ...... if you can reach a plug ..... or look into a newer, more powerful battery.

That reminds me of back-in-the-day when I was living in CT. One morning it was -18 degrees F (not wind chill) ...... just -18.

I had two newer vehicles in my garage and neither would start.

I also had a 1956 Ford step side pickup truck, with a 1957 Chevrolet 283 cu in V-8, parked outside. I'll be damn, it started right up.......:iono:

THE END


humfrz

Yeah sometimes when a car battery is really low (some manufacturer's are worse like this than others- Jeeps and Chryslers in general are bad, some Toyotas) when you jump it off it'll run like ass for a while but in time it'll come back around and be fine.

Don't sweat it. Just make sure youo know why the battery went dead and take care of that.

'Tis the season.



...in the Northern hemisphere.

What always makes me laugh- here in Florida when the temp gets into the 50's and someone calls for a jump they always say "must be the cold" LOL. People here don't know cold- any temp above the 20's has no effect on how many jump starts our company does. When I did this job in Maine, when the temp got into the teens- THEN batteries started going left and right. But 50's? That battery was going to die today no matter what buddy. But I think it's hilarious what people here call "cold"

The rough idle is probably normal, because if the battery is low enough, it's like unplugging the battery, and the ECU need to re-learn the idle.
The rev-limitter at 2300rpm is kinda strange.

I have let teh car heat for half an hour and it was still fuckeed
Up. When i restarted it it was ok. I know maybe i damaged my battery when i was in a 4 day festival and I found the car dead because the trunk was a little opened with the light on...

If I were you I'd just buy a new battery. In my experience, once you kill a car battery 2-3 times, it never recharges to full capacity. They don't like deep cycling until being completely dead.

I killed my battery to the point that my horn didn't work - it was never the same afterwards.

you might pick up a Subaru block heater and a battery warmer.


not a fan of 'jumping' or being 'jumped'. transients came make things go poof.