For the past few months my car has felt a bit doggy and I chalked it up to high temps and humidity. Shifting felt a bit off and throttle response was laggy. My 6 y/o OEM battery had been showing signs of death for about 3 months as well (ie really hard and slow starts). I replaced the battery on Saturday and was shocked at how much more responsive the throttle and tranny were. There's no way a dying battery can affect a car while running, right? I use to laugh at people that reset their G and Z ecus every 2 months or so to restore response and power, but now I'm wondering if there is some truth to it.

 

my battery died when I was driving. Scary experience. So yes it can affect a car while its running.

 

My car battery died after not turning it on for a month. But it was the OEM battery and needed replacing anyways.

Is this normal? On a cold morning in California, it takes my car longer than usual to start the engine. Or could it be spark plugs...

 

If the battery dies while your driving the car should still be able to run. Now if ur alternator goes out at the same time then ur screwed

 

I just did my first ECU reset last week and did notice a small difference, but what are you thinking would be the benefit of resetting frequently? I dont reinstall Windows every couple of weeks on my computer, only when things start to slow down. Unless you are noticing a difference in performance or shifts, why reset?

 

Over time, the car "learns" fuel strategies. What is has is called "Short Term Fuel Trim" and "Long term fuel trim". If you have an OBD2 scanner with live data, you can see these numbers real time.

STFT takes the instantanous O2 sensor readings and adjusts A/F ratio. Usually it's within 10% of a specific known value. Overtime, if the computer noticed your STFT is lean or rich, it will adjust the LTFT to keep the average ratio within center range. In other words if it notices your short term mixture is rich, it will adjust your mixture for a leaner mixture over time.

Once dialed in, you get optimum fuel economy. When you reset, you wipe out everything your car has learned and start fresh, which sometimes results in a "peppier" feel until the car relearns fuel strategy over the next few weeks.

It also forces the car to relearn A/T shift strategy as well.

 

oh man, you people do anything to feel like you have more power!

 

^Though strictly speaking, A computer will run really good with a fresh install of windows every couple of weeks

 

I don't do it. I'd rather have the fuel economy.

 

It really has nothing to do with power, but there is no doubt the throttle and tranny is more responsive right after a reset. Power wise, I can't tell any difference. Throttle tip-in and shift firmness under part throttle shifts is much better. I've tried the reset twice over the past 3 weeks now. Same result. But like others have said, gas mpgs go in the tank. I loose about 15% mpg on the reset. I've know this for years. My old VQ30 did the same thing. Another problem is I drive pretty sedately 90% of the time so the ECU and TCM quickly learn my driving style within a week so the throttle response becomes a bit deadened and tranny shift firmness except at WOT is softened. It's not horrible by any means, but I'd much prefer the initial throttle and shift firmness feel all the time.

 

does clearing the ECU via scan tool work the same way as resetting via battery cables?

i do the ECU clearing when i get bored. I know by clearing it LTFT and STFT are reset. Tranny probably still remembers