So I went to Canadian Tire to replace my car battery last week and haven't driven my car until today. I found that after I started up my car, my rpm would drop to less than 300 and sometimes the car shuts itself down OR ...if the rpm comes back up then everything'd be normal again...

I am kind of worried as this never happened to my car before I replaced my battery... so I brought her back to CT and the mechanic there told me that since they left my car in the shop overnight (without a battery) while waiting to order the correct battery to the store, the ecu was reset and therefore, it needs to re-learn the amount of fuel needed to be sent to the engine and my driving behavoiur.. meaning.. it's not that big of a deal as this symtpon will gradually disappear after i drive her for some times.....


being a relative car noob like myself.. i would like to get a second opinion from experts on this forum.....

is he telling me the truth?? does it make any sense to you guys?? if true, then how long does it usually take for ecu to learn the correct amount of fuel needed to be sent so i don't have to hit my pedal like a **** every time i am starting my car?? (i am not seeing any red warning lights on my panel at the moment so i suppose there is nothign wrong with my ecu ..)

Thanks in advance for all your help guys!!!


I hope I asked a legit question here. I have tried the search button but i wasn't able to locate a thread that has related issues.

oh... and I drive an 04 G35 Coupe 5AT if that's any useful information....


Robin

 

Yup, ECU needs to go through re-learning process. It'll be fine after you put a few more miles on her.

 

Very legit question, Robin.

I agree with Sponger: You should be fine Robin......ECU needs to relearn.

Let's hope for more springlike weather so that we may enjoy our rides again.

Colin.

 

It's the throttle position sensor going nuts trying to relearn... reset your ECU if you can't drive.

 

As others have said it should correct itself fairly quickly.

 

it would make sense that some throttle sensitivity would vary a bit when driving... but if the car is not idling properly, there's obviously something else wrong.

it almost sounds like your maf sensor might need a cleaning or something. i'm no expert on it... just remembering what other's have done on the boards when they had idling problems.

 

^ Same here... I don't recall idling issues with an ECU reset

 

sorry I dind't make it clear in my first post....

when the car is idling.. everything is okay just as before.. the rpm only drops to below 300 (for a split second) when I first started it up...and it doesn't happen as long as I press the gas pedal at the same timei I turn on the ignition (however.. it is still weird to me as I never had to press the gas pedal when I started my car before...)


I did somore search on google and here is a piece of article I found online:

Accelerator Pedal Release Position Learning
Operation Procedure

1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning
Operation Procedures

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning (Throttle Position Learning)

It is better to count the time accurately with a clock.

1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.



Now.. my question is.. do I MUST follow the steps above in order to have my ecu re-learned all the logic correctly or this is just somethign that will speed up the whole process but not mandatory to every G35 driver after the battery is reconnected?


Someone please educate me...


thanks in advance...

 

Altenator

 

I'm having a similar issue, but only occurs when the car is already warm. Some times the idle drops and hesitates or the engine shuts off. If I tap the gas after it's started it's okay. No issues when driving or from a cold start. The dealer and my mechanic said that I should get my injectors cleaned. Did that, but the problem still persists. Still don't know what could be the cause.

 

try cleaning the throttle body...many people have come across this problem when disconnecting the battery.

https://g35driver.com/forums/engine-...-start-up.html

and after doing that, if you have any rough idling...then try what you've posted, the throttle position learning procedure.

here's some DIY vids...

https://g35driver.com/forums/g35-sed...eo-series.html