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Old 01-14-2021, 10:01 AM   #1
sb04wrx
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Default Cold Idle issues after Pro-tune

My car was dyno tuned back in November by a fairly reputable shop. The car ran great and pulled hard but as mornings started to get colder the car has been having a rough time on first start. It sputters and coughs as if it caught the covid. As the car comes up to temp the idle issues subside and the car runs as expected. I've tried talking to the tuner and he seemed more than willing to help and asked for a few logs which I happily sent. 2 weeks later and I haven't heard anything. Before I call back and ask why my car runs like crap on cold idles I'd like to know if anyone here notices anything strange about any of the values on my log.

Here's the log for reference:
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Old 01-14-2021, 10:23 AM   #2
Zak6182
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Do you have TGV / air pump deletes?
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Old 01-14-2021, 10:34 AM   #3
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I do. IAG tgv deletes.

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Do you have TGV / air pump deletes?
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Old 01-14-2021, 11:13 AM   #4
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Quote:
Originally Posted by sb04wrx View Post
I do. IAG tgv deletes.
My car does this as well. I let it run for a few minutes before I pull away, same for when I stop at a store for a min. When I come back out to the car I let it idle for a min before I touch the gas and it clears itself up. This is worse in the cold but it also happens when warm. I'm assuming it's burning off excess fuel that pulled because of the tgv deletes.
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Old 01-14-2021, 11:30 AM   #5
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Mine does it too. Once it warms up it wont do it again until its cold. I've seen a few threads where it seems pretty common but can be tuned out. I worked with my tuner and we got it better but not 100% correct. When I start to feel it stumble I barely tap the gas a few times and it helps quite a bit.

If you watch your AF you can see it start to run rich and you'll know when its about to do it.
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Old 01-14-2021, 11:31 AM   #6
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Interesting. What I'd really like to know if this can be corrected by the tuner or if it's the nature of running tgv deletes. I don't know too much about tuning but if it's a matter of an over rich condition can't that be corrected by the tuner? Unless it's tuned as such to have adequate fueling in both hot and cold conditions.


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My car does this as well. I let it run for a few minutes before I pull away, same for when I stop at a store for a min. When I come back out to the car I let it idle for a min before I touch the gas and it clears itself up. This is worse in the cold but it also happens when warm. I'm assuming it's burning off excess fuel that pulled because of the tgv deletes.
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Old 01-14-2021, 11:43 AM   #7
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I'm not a tuner by any means but from my research it seems like the issue happens when its cold and going from open to closed loop. I think during that period the ECU is "hunting" for the right AF and it takes a second to find it due to TGV's not being there.

I recently read something on PhatBotti's website that it was normal and could be helped but not always completely corrected. I'll try to find it again.
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Old 01-14-2021, 11:55 AM   #8
sb04wrx
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Quote:
Originally Posted by Zak6182 View Post
I'm not a tuner by any means but from my research it seems like the issue happens when its cold and going from open to closed loop. I think during that period the ECU is "hunting" for the right AF and it takes a second to find it due to TGV's not being there.

I recently read something on PhatBotti's website that it was normal and could be helped but not always completely corrected. I'll try to find it again.
This makes sense. Thank you for the info. I was concerned at first the fuel pump was faulty or something else was at play.
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Old 01-14-2021, 03:13 PM   #9
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our built EJ207 with the original JDM STI intake (no tgv) does that when cold. we just let it warm up before driving out. But we always warm up all my cars before heading out. My built Evo 8 is even worse. cold or not, it wants to be warmed up.
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Old 01-14-2021, 04:12 PM   #10
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Quote:
Originally Posted by Whooopasss View Post
our built EJ207 with the original JDM STI intake (no tgv) does that when cold. we just let it warm up before driving out. But we always warm up all my cars before heading out. My built Evo 8 is even worse. cold or not, it wants to be warmed up.
I will warm my car up when time allows and if the gf is already awake, but I feel bad for letting the car idle for an extended period of time in the garage. Garage also happens to be right below our bedroom so... she ain't a fan. I'll just learn to live with the sputtering now that I know it's somewhat normal. Thanks for your response.
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Old 01-15-2021, 04:44 PM   #11
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Step zero is for you to do this:

https://forums.nasioc.com/forums/sho...d.php?t=781242

Once this is done, then and only then will you have removed the #1 cause of wonky idle from the equation.
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Old 01-20-2021, 11:58 AM   #12
sb04wrx
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Quote:
Originally Posted by Unabomber View Post
Step zero is for you to do this:

https://forums.nasioc.com/forums/sho...d.php?t=781242

Once this is done, then and only then will you have removed the #1 cause of wonky idle from the equation.
Will look into this this weekend. Thank you.
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