Idle RPM issue after battery change

[googleman]

Has anyone experienced the following issue after a battery change? I changed the car battery and the air filters last week. Ever since, the idle RPMs are lower than usual. RPM is slightly above 600, while before the change it was between 800 - 1000. It is not low enough to cause stalling or vibration, but I am still curious why it might be. I also feel like even in the DS mode there is a subtle lag in responsiveness when I press the gas pedal, which didn't exist before.

The new battery could not be the issue, I checked the voltages, connectors etc and everything seems normal.

The new filters are not the issue either. I put back the old ones just to see but the RPM is still low.

Could this be some of the ECU settings being reset after the battery change and the car is relearning everything? It has been a week but there is no improvement.

[NJGuy]

My first guess would be that the ECU settings had been erased when the battery was disconnected.

AWDG8 put up this post about resetting the ECU, accelerator pedal position, and throttle valve closed position:
ex-shuts-down-at-higway-speeds-t577906.html#p6498503
Perhaps doing these might help.

If he doesn't chime in here, maybe you can ask him about this via PM.

[googleman]

My first guess would be that the ECU settings had been erased when the battery was disconnected.

AWDG8 put up this post about resetting the ECU, accelerator pedal position, and throttle valve closed position:
ex-shuts-down-at-higway-speeds-t577906.html#p6498503
Perhaps doing these might help.

If he doesn't chime in here, maybe you can ask him about this via PM.

Thanks for the feedback. Before attempting any of these. Do these steps have to be completed after every battery change? Does the dealer perform these when they change the battery? I was actually surprised that after I changed the battery most of my settings were still intact, like bluetooth pairing etc. I wonder why the ECU resets and not the others.

[NJGuy]

Thanks for the feedback. Before attempting any of these. Do these steps have to be completed after every battery change? Does the dealer perform these when they change the battery? I was actually surprised that after I changed the battery most of my settings were still intact, like bluetooth pairing etc. I wonder why the ECU resets and not the others.

I wish I could tell you, as I don't know the answers. Your guesses would be as good as mine.

If I were in your shoes, I think I'd just go ahead and try them. Other than a few minutes of your time, it doesn't seem like you have anything to lose here.

[XIS]

I would try that too. I would think there must be some relation there. Re-set the ECU and let us know if that helped.

[AWGD8]

Has anyone experienced the following issue after a battery change? I changed the car battery and the air filters last week. Ever since, the idle RPMs are lower than usual. RPM is slightly above 600, while before the change it was between 800 - 1000. It is not low enough to cause stalling or vibration, but I am still curious why it might be. I also feel like even in the DS mode there is a subtle lag in responsiveness when I press the gas pedal, which didn't exist before.

The new battery could not be the issue, I checked the voltages, connectors etc and everything seems normal.

The new filters are not the issue either. I put back the old ones just to see but the RPM is still low.

Could this be some of the ECU settings being reset after the battery change and the car is relearning everything? It has been a week but there is no improvement.

Our EX35 stock RPM at Idle (engine @ normal operating temp) is around 650 RPM. Since my car is tuned , I have an access to the ECU parameters. I noticed that our EX35 idle RPM varies at startup depending on the ambient temp, but it will settle down to 650 RPM after 5+ minutes. I can access that startup table RPM and take a screen shot if prefers. I was surpised how low our idle RPM is set. Currently, I adjusted mine to 775RPM idle. (Uprev Tuner software)

I am not sure if it was cold when you noticed that your idle RPM is at 800-1000RPM , but that should go back to 650RPM when the engine heats up.

BTW, I am not 100% sure, but I believe removing both battery cable might reset your fuel learning curve table. (Reason why DS mode is acting up, mostly its the fuel mixture issue probably and not DS mode) The Computer is relearning to readjust air/fuel mixture and will tend to set closer to Manuf. Fuel table setup in the ECU after driving it for a few days. I always feel that everytime I clear this fuel learning curve data using the Uprev tuner software, the car seems to have a better pickup or more responsive. Maybe it is a good idea to do the pedal dance once a month.
I forgot to mention, mine is 2008 model. I'm not sure if the newer models have higher idle RPM.

So there are 2 options to reset the ECU. Either you remove the battery cable for a while or do the pedal dance link below. ( obviously, you did the first one already ). Just drive it until the fuel curve is relearned (2+ weeks)
Pedal dance is the fastest way to reset the ECU with out getting your hands dirty

Here it is..

http://m.youtube.com/watch?v=95WszTnphP ... 5WszTnphPI

[googleman]

Thanks! I actually did the pedal release position and throttle valve learning procedures. Not absolutely sure if they did it or it is me driving the car more but responsiveness seemed to have improved the last two days. The funny thing is the lag issue was only with the DS mode; D mode has been more responsive than it was before the battery change.

Incidentally, I found instructions for "Infiniti EX Idle Air Volume Learning Procedure" from another forum but didn't attempt to do it as it looked trickier than the other two I did.