smartidiot

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.

Jay'Z

iTrader: (118)

Nice SN..... He is prob right.. Just keep driving it.. It shouldnt take more than a few days.......

smartidiot

thanks JayZ..

does that mean what the mechanic told me is true?? how come the same thing didn't happen on my dad's Volvo S80 when he changed his battery..... (or mabye i just wasn't aware of it...)

Jay'Z

iTrader: (118)

Volvo isnt a 350z first off.. Secondly are you sure you bought the correct battery? Did you get an Optima R34?

maroli

shouldn't happen, I don't think. I had my car without a battery for a week and did not experience such a thing. The ECU FINE-TUNES itself to your style, does not throw the fuel metering out of wack. Try cleaning the battery poles and clamps

smartidiot

um.. i drive an 04 G35 Coupe ..brother of 350Z....


i simply went into the shop and asked the mechanic to find me the best compatbile battery...there is only one in their database.....

TreeFiddyZee

iTrader: (19)

Maybe you didn't need to replace the battery in the first place. Maybe your alternator is taking a dump.
Did you check the battery cables and make sure they are attached securely?

smartidiot

well. i was pretty sure my battery was dead because i wasn't able to start up my car after i filled the gat at a gas station.. all my lights went out and i wasn't able to move my automatic driver seat......i need to have someone give me a boost so i could drive to CT that day.....

TreeFiddyZee

iTrader: (19)

Kinda rules out the alternator I guess.

bizcotch

iTrader: (5)

Happened to my Z after disconnecting the battery for a while. Just do the "relearning procedure" and that should take care of it

smartidiot

there is such thing as learning procedure??

mind to elaborate?!?

michaeljr6

iTrader: (14)

just drive the car, you should be fine. that's the procedure.

bizcotch

iTrader: (5)

It's basically a series of steps you do to reset the computer and relearn its air/fuel mixture, intake etc.

I'll look for the steps and posted on here unless someone else beats me to it. You can also use the search feature

smartidiot

Thanks in advance for your help..so is it something that I "must" do?? Or the car will basically learn by itself after a while without me doing anything (other than driving, of course)....

bizcotch

iTrader: (5)

https://my350z.com/forum/maintenance...-required.html

bizcotch

iTrader: (5)

It's definitely something you can do to get rid of that annoying stalling. It may take several attempts, however, it does work. Keep in mind that the timing and order of each step is crucial . Good Luck!! and may the force be with you

350z-Jim

iTrader: (1)

The mechanic at CT was right. Just keep driving it, the problem will go away but it takes some time. This happened to another guy and it took 500km before it went normal on him. THe computer needs to re-learn the fuel adaptation based on our climate. Remember that the computer makes changes to the car based on Air Temp, Pressure etc.. When reset its gonna choke while it sorts that all out again. They are slow learners.

They way you can confirm this is if you go WIDE OPEN throttle the car should accelerate normally because in OPEN LOOP the ECU ignores most of those inputs from the various sensors. So if under hard acceleration the car is fine but putting around town it drives like a bag of crap, your fine. Just keep driving it and eventually it will be ok.

smartidiot

Thanks for your useful response Jim.

I did some more research on Google this morning (well it's Friday morning...) 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 driver after the battery is reconnected?


Thanks again

Jay'Z

iTrader: (118)

You smart idiot!! If you do another relearn procedure youll have to start all over relearning!!

edvy

it happened to one of my customer and my Z b4. i fixed the problem and it was really stupid. PM me if u need help

and it got nothing to do with relearning , if this is the same problem