ECU Relearn (warm start stalls)
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ECU Relearn (warm start stalls)
Recently I disconnected by neg battery terminal to store the car for 3 weeks. I just got back from vacation and noticed that the car will stall on warm starts. On cold starts in the morning the car idles fine, but if I start the car after it's warm, it will fire up and stall almost right away. Sometimes it works, but most time it stalls. If I give it an initial tiny bit of gas, it will idle fine on warm starts. I have read numerous posts about resetting the ECU through technosquare and tried it myself with no luck.
My question is will the ECU eventually relearn itself such as the proper idle rpm? If so, how long does this actually take? This never happened prior to disconnecting the battery.
PS: Car is a 2003 with about 70k miles. No engine mods at all.
Any help appreciated! Thanks!
My question is will the ECU eventually relearn itself such as the proper idle rpm? If so, how long does this actually take? This never happened prior to disconnecting the battery.
PS: Car is a 2003 with about 70k miles. No engine mods at all.
Any help appreciated! Thanks!
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Alright, it's been 3 days now and problem still occurs. Weird thing is sometimes it chokes and then magically revives itself and then idles normally... other times it just completely stalls out...
I'll keep monitoring it everyday.
I'll keep monitoring it everyday.
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ezatt1995 (10-06-2021)
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I'm hoping the ECU should eventually learn by itself.. it's kinda misleading if we had to reset the ECU and manually relearn all those throttle/pedal/idle settings described by others.. A battery swap should be fairly common, and I wouldn't expect Nissan to design something so complicated for the typical consumer to Know and HAVE to perform such a task....
Just doesn't make sense to me that a simple battery change would "require" a full ECU reflash just for the car to know how to idle properly...
Just doesn't make sense to me that a simple battery change would "require" a full ECU reflash just for the car to know how to idle properly...
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For a tuned/modified ECU.. I can see why a manual recalibration makes sense.
My comment is more referring to the average Z buyer who never modifies their car but has to change a dead battery over the years. It would be ridiculous if you had to manually reset the ECU/idle/throttle position just for changing a dead battery...
My comment is more referring to the average Z buyer who never modifies their car but has to change a dead battery over the years. It would be ridiculous if you had to manually reset the ECU/idle/throttle position just for changing a dead battery...
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For a tuned/modified ECU.. I can see why a manual recalibration makes sense.
My comment is more referring to the average Z buyer who never modifies their car but has to change a dead battery over the years. It would be ridiculous if you had to manually reset the ECU/idle/throttle position just for changing a dead battery...
My comment is more referring to the average Z buyer who never modifies their car but has to change a dead battery over the years. It would be ridiculous if you had to manually reset the ECU/idle/throttle position just for changing a dead battery...
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Same issue
Hey guys. I also have an 03 with 75k miles on it now. I recently purchased a new battery because my old one was dying. I've had the new battery now for two months with no issues. When I started the car while it was already warm today, it bogged down and stalled for the first time. On a cold start it's totally fine. Sometimes it will stall when it's warm, sometimes it will keep afloat but chokes. The car starts beautifully because of my Optima battery. Recently, I replaced my stock head unit and the Service Engine Soon light came on. I reset the ECU to get rid of it (there was nothing to service, my car has had its tranny fluid changed very recently, oil, air filter, coolant flush etc etc.... all the usual stuff). I did this about a week ago..... and so I'm guessing this has kinda screwed with the idle.
Do I also leave this alone???? Is the ecu recalibrating itself because I reset it a week ago? Clon, is yours still doing it? It was 100% fine before this afternoon so.....
Do I also leave this alone???? Is the ecu recalibrating itself because I reset it a week ago? Clon, is yours still doing it? It was 100% fine before this afternoon so.....
#15
I have the same exact problem as well I have 03 350z manual and I have disconnected the batteries because I was installing subs in it. It was working fine first times I disconnected the batteries but last time I had to disconnect it because I was fixing my sub box so I had to take everything out. The day after I already had connected the battery my car started to stall on hot starts I am not sure if disconnecting and connecting the battery so much that it causes this problem. It turns on normally on cold starts but on hot starts It dies unless I rev it up a little bit and it starts to idle fine. Anyone know how to fix this?
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Eventually it ECU will just calibrate itself. It takes anywhere between 2-4 weeks to be fully back to normal. I disconnect my battery as least once a year for vacations...
#18
So let me get it right... It is normal to have your 350z die on you only on hot start and start up find on cold start? and what you have to do is just wait for the ECU to recalibrate and it will start up correctly? correct me if im wrong thank you!
#20
ok sweet well im glad to know that Its not a serious problem and its a self fix haha.. do you know if theres anyway I could do to just fix it by hand or a way to do it quickly?