Cold Idle issues after Pro-tune

sb04wrx · 01-14-2021, 11:01 AM

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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Zak6182 · 01-14-2021, 11:23 AM

Do you have TGV / air pump deletes?

sb04wrx · 01-14-2021, 11:34 AM

I do. IAG tgv deletes.

Quote:

Originally Posted by Zak6182

Do you have TGV / air pump deletes?

pickleSlapOG · 01-14-2021, 12:13 PM

Quote:

Originally Posted by sb04wrx

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.

Zak6182 · 01-14-2021, 12:30 PM

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.

sb04wrx · 01-14-2021, 12:31 PM

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.

Quote:

Originally Posted by pickleSlapOG

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.

Zak6182 · 01-14-2021, 12:43 PM

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.

sb04wrx · 01-14-2021, 12:55 PM

Quote:

Originally Posted by Zak6182

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.

Whooopasss · 01-14-2021, 04:13 PM

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.

sb04wrx · 01-14-2021, 05:12 PM

Quote:

Originally Posted by Whooopasss

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.

Unabomber · 01-15-2021, 05:44 PM

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.

sb04wrx · 01-20-2021, 12:58 PM

Quote:

Originally Posted by Unabomber

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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01-14-2021, 11:01 AM	#1
sb04wrx Scooby Specialist Member#: 204541 Join Date: Mar 2009 Chapter/Region: Tri-State Location: Collegeville, PA Vehicle: 2004 VF48 WRX Wagon Java Black Pearl	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: * Registered users of the site do not see these ads.

01-14-2021, 11:23 AM	#2
Zak6182 Scooby Newbie Member#: 481754 Join Date: Feb 2018 Location: Beaufort, SC Vehicle: 2017 STi Base Black	Do you have TGV / air pump deletes?

01-14-2021, 12:30 PM	#5
Zak6182 Scooby Newbie Member#: 481754 Join Date: Feb 2018 Location: Beaufort, SC Vehicle: 2017 STi Base Black	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.

01-14-2021, 12:43 PM	#7
Zak6182 Scooby Newbie Member#: 481754 Join Date: Feb 2018 Location: Beaufort, SC Vehicle: 2017 STi Base Black	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.

01-14-2021, 04:13 PM	#9
Whooopasss Scooby Newbie Member#: 82677 Join Date: Mar 2005	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.

01-15-2021, 05:44 PM	#11
Unabomber 👏 Big Ron 👏 Moderator Member#: 18062 Join Date: Apr 2002 Chapter/Region: MAIC Location: I can save you a ton of cash Vehicle: on car parts so PM me b4 j00 buy	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.