Did my tune get messed up sitting over the winter?
03-10-2020, 07:08 PM
#1
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Did my tune get messed up sitting over the winter? Like I said in the title, I don't know what could've happened but I went to start my car after sitting for a couple months and it ran like ****! Pig rich as in 9-10 afr and very bad fumes, misfires, etc. Then my CES came on and when I checked codes got these 3 codes. P0102,P0155,P0045? The one code for the 02 sensor heater could apply but the other 2 codes, 102 is for the maf sensor(I'm running SD now) and the 045 is for Supercharger/turbo boost? I have no idea where this one comes from. I re-flashed it with my tune and it ran fine after that but I was just curious what could cause this to happen? I've never heard of it.
Also when I went to flash it I got a message saying something about operating systems being different and I had to do the "special" flash that said might brick my PCM? Luckily it went fine and didn't brick it but what could be going on here?
Also when I went to flash it I got a message saying something about operating systems being different and I had to do the "special" flash that said might brick my PCM? Luckily it went fine and didn't brick it but what could be going on here?
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G Atsma (03-10-2020)
03-13-2020, 12:49 PM
#5
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03-13-2020, 01:19 PM
#6
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that an ECM would loose anything from the tune file.Perhaps sitting up too long without being started the fuel in the system went South, ethanol based fuels can certainly cause an issue if it sits up too long.
03-13-2020, 02:40 PM
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03-13-2020, 03:07 PM
#8
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Just spitballing, but anytime you reflash it immediately goes into learn mode. So maybe the gas went bad from sitting, and the ECU having been well adapted prior to last shutdown wasn't relearning fast enough to compensate. Then reflashing reset everything and it's giving the PCM time to readjust. Don't think that would explain the code though.
03-13-2020, 04:25 PM
#9
Just spitballing, but anytime you reflash it immediately goes into learn mode. So maybe the gas went bad from sitting, and the ECU having been well adapted prior to last shutdown wasn't relearning fast enough to compensate. Then reflashing reset everything and it's giving the PCM time to readjust. Don't think that would explain the code though.
03-14-2020, 01:43 PM
#11
The tune doesn't go bad. It's stored in flash memory that should never deteriorate (not within our lifetimes). If any bits actually did change, the PCM has checksum logic to detect it, and it won't run the engine or even let you reflash it - if the flash chip contents somehow got corrupted, then the flash chip can't be trusted and PCM pretty much bricks itself. Checksums aren't perfect, but it is highly unlikely that two bits flipped and they perfectly complemented each other so as not to break the checksum.
But reflashing does resets all of the learned parameters, so it's possible that the values your PCM learned the last time you drove were not suitable for something about the current situation. Maybe fuel, maybe temperature, maybe something else, I dunno.
I think it's more likely a problem with a sensor or wiring. If I'm right about that, the problem will come back after some driving. If not then I'm going back to the learning theory... and the problem will come back after another stint in storage.
But reflashing does resets all of the learned parameters, so it's possible that the values your PCM learned the last time you drove were not suitable for something about the current situation. Maybe fuel, maybe temperature, maybe something else, I dunno.
I think it's more likely a problem with a sensor or wiring. If I'm right about that, the problem will come back after some driving. If not then I'm going back to the learning theory... and the problem will come back after another stint in storage.
03-14-2020, 04:04 PM
#12
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03-14-2020, 04:11 PM
#13
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The tune doesn't go bad. It's stored in flash memory that should never deteriorate (not within our lifetimes). If any bits actually did change, the PCM has checksum logic to detect it, and it won't run the engine or even let you reflash it - if the flash chip contents somehow got corrupted, then the flash chip can't be trusted and PCM pretty much bricks itself. Checksums aren't perfect, but it is highly unlikely that two bits flipped and they perfectly complemented each other so as not to break the checksum.
But reflashing does resets all of the learned parameters, so it's possible that the values your PCM learned the last time you drove were not suitable for something about the current situation. Maybe fuel, maybe temperature, maybe something else, I dunno.
I think it's more likely a problem with a sensor or wiring. If I'm right about that, the problem will come back after some driving. If not then I'm going back to the learning theory... and the problem will come back after another stint in storage.
But reflashing does resets all of the learned parameters, so it's possible that the values your PCM learned the last time you drove were not suitable for something about the current situation. Maybe fuel, maybe temperature, maybe something else, I dunno.
I think it's more likely a problem with a sensor or wiring. If I'm right about that, the problem will come back after some driving. If not then I'm going back to the learning theory... and the problem will come back after another stint in storage.
Well, that doesn't make me feel better. lol The part also about when I tried to "write vehicle" and it wouldn't let me saying something about operation systems being different kinda freaked me out also, Only let me do a "write entire" and had the red brickable warning with it but luckily it went through. I'm gonna assume both these problems are connected somehow. Just gotta figure out why so it doesn't happen again.
03-14-2020, 05:46 PM
#16
Well, that doesn't make me feel better. lol The part also about when I tried to "write vehicle" and it wouldn't let me saying something about operation systems being different kinda freaked me out also, Only let me do a "write entire" and had the red brickable warning with it but luckily it went through. I'm gonna assume both these problems are connected somehow. Just gotta figure out why so it doesn't happen again.
I've been screwing with idle tuning on my car for a while, and it's pretty common to have a tune that barely idles or even doesn't idle after the flash, but then learns to idle OK after some driving. That's mostly just learning in action.
There's also a desired airflow (or base airflow) table that helps determine how much to open the throttle, based on coolant temperature, and it's possible to have that dialed in nicely for a warm engine but still way off for a cold engine, or vice versa. If the temperature changed a lot between when you last drove it before storage and when you took it out of storage, that could be a factor here.
03-14-2020, 05:57 PM
#17
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I wouldn't lose any sleep over the app forcing a "write entire." There are a bunch of different operating systems for Gen3 PCMs, and the one you had wasn't supported by (your version of) the app you were using. It's no big deal. The differences between them, as far as I know, are mostly pretty trivial. I'd just keep driving and see what happens.
I've been screwing with idle tuning on my car for a while, and it's pretty common to have a tune that barely idles or even doesn't idle after the flash, but then learns to idle OK after some driving. That's mostly just learning in action.
There's also a desired airflow (or base airflow) table that helps determine how much to open the throttle, based on coolant temperature, and it's possible to have that dialed in nicely for a warm engine but still way off for a cold engine, or vice versa. If the temperature changed a lot between when you last drove it before storage and when you took it out of storage, that could be a factor here.
I've been screwing with idle tuning on my car for a while, and it's pretty common to have a tune that barely idles or even doesn't idle after the flash, but then learns to idle OK after some driving. That's mostly just learning in action.
There's also a desired airflow (or base airflow) table that helps determine how much to open the throttle, based on coolant temperature, and it's possible to have that dialed in nicely for a warm engine but still way off for a cold engine, or vice versa. If the temperature changed a lot between when you last drove it before storage and when you took it out of storage, that could be a factor here.
Yeah, I know SD tunes aren't really good for cold weather. It is running good now though and it'll be coming out soon so I'll just drive it and see. I was just thinking the worst when I first started it, never ran so bad and I figured it was something serious. Thanks
03-14-2020, 08:38 PM
#19
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03-14-2020, 08:56 PM
#20
2. Speaking generally a stock PCM learns fuel trims and idle air trims, both have short terms and long terms
3. If the car has been tuned, you can disable the long terms and/or also the short terms.
4. You can tune it to run open loop completely, run closed looped, with STFT and or LTFT.
5. Regardless...a tune doesn't go bad...