Disconnecting My Battery After Driving

NewToFord

Member
Oct 7, 2008
318
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CT
Some have you may have seen my other post about my surging idle. I have gone through the checklist. The idle is gets choppy sometimes but not other times. One minute its perfect, next time its all over the place. After I drive the car and I pull it in the garage I always disconnect the battery. Its a habit. I am scared the car may burn. I had another 93 fox, that started buring under the hood after the car was shut off. To this day I'm still not sure why. So my question is, when I disconnect the battery how long does it take the ecm to realearn everything? I will connect the battery, drive the car to work, leave it connected and drive home 9 hrs later. Has the ecm already relearned, or does it take so many heat cycles? The car has a sct base chip. It will be tuned in a few more hundred miles. Is there any chance of these cars burning while they sit with the battery disconnected and the key out?
 
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It takes 15-30 minutes of steady speed driving for the computer to relearn all the settings.


The fire was likely due to a bad power wire connector on the alternator or a shorted diode inside the alternator.

Instead of paranoia, spend some extra $$$ on agreed value insurance and leave the battery connected. Eventually, you'll mess up and short the battery or forget to connect it properly and then really have problems.
 
Invest in a fire extinguisher for your car and garage. When you turn a vehicle off after driving the engine actually heats up before cool down. Common thing that happens to them all. All their needs to be a fire is some sort of catalyst. If you want to continue with the battery thing, get a terminal disconnect. It's a knob that's on the terminal (negative) that you just twist. They sell them at most auto parts stores. Sorry to hear of your bad luck.
 
I do have a insurance policy for the car. I also have a fire extingusher too. I'm not sure why my other car burnt. It was right after I turned the car off. The fire was on the drivers side under the hood. I'm not sure if it started on the soleniod or the coil. I was able to put it out and eventually fix the car. I'm just glad it happened in a parking lot and not my garage. So now you can understand my parniod ways of thinking
 
I had a drain on my battery shortly after buying the car. Until I took the time to trace it out, I unhooked the battery every time I parked the car almost. I was also trying to get it to idle correctly. Did everything on the checklist and found an effed up air intake temp sensor. But even after all that it still stalled on start up and acted dumb. I finally got to the drain. Replaced the glove box light switch (source of the drain). After the battery was left hooked up for a few days the car ran perfect. The computer could never learn what was going on until I left the battery hooked up. I was chasing a ghost that I created.
 
I am sure with the SCT chip if you were to pull codes you would get a code 15 Keep Alive Memory. With that your ECU would have to re learn after each start anyway just as if you disconnected your battery each time if I am not mistaken.

I have a SCT 3 Bank Eliminator chip, with the chip installed I get a code 15. Plus I have the battery disconnect that darthcual mentioned on my Mustang because I don't drive mine that often and my battery will drain down after a few months of sitting. But mine will idle fine after start up when the battery has been disconnected.