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Old 10-18-2017, 07:59 AM   #1
Co1lt45magnus
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Default AF Learning 1 - Cold weather and you

Recently I had a bit of a freak out in one of the COBB threads due to having a pretty decent amount of knock regularly. As it turned out, even though I was using Shell 93.. the Shell station I was using is garbage. As soon as I was on empty I filled at a completely different, more popular Shell station, and haven't seen ANY knock whatsoever since.

But this morning as I pulled in to park at my job, I notice as soon as I was idleing my AF Learning 1 had dropped to about -17... now it's normal for me to see anywhere from -5 to -14 at idle on the MAP 93 octane tune im running, but I don't think I've ever seen it go as low as -17, this would normally make me think there's a leak somewhere, however, I just took my car to the dealership recently and they did a smoke test through everything while I was there. No leaks found of course, but I did a fair bit of reseating and tightening when the knock was present prior to them checking. Before anyone asks the MAF is clean as a whistle (but I wouldn't put my mouth on it) and I got a brand new air filter from dealership. I also just did spark plugs about 500 miles ago. So nothing should be wrong, right?

Im not sure if this has relevance to the numbers I'm seeing, but this morning is one of the first days it's been cold here (like 38 degrees F outside temp) so I am just curious, can the cold temperature effect fuel trims THAT significantly? I always knew peak boost is lower in cooler temps due to denser air, but did not learn how this could effect AFRs...

Mind you, my wideband is still dead nuts at 14.7 and hardly ever moves while idleing. Yesterday it was even colder at like 35 degrees F, but I never saw AF Learning 1 drop lower than -11.... so I'm just asking in general to the tuners out there and to the people regularly monitoring their AF Learning 1... is this normal for the FA and has anyone else experienced a low figure like I have?
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Old 10-18-2017, 10:13 AM   #2
ericdet
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Quote:
Originally Posted by Co1lt45magnus View Post
Recently I had a bit of a freak out in one of the COBB threads due to having a pretty decent amount of knock regularly. As it turned out, even though I was using Shell 93.. the Shell station I was using is garbage. As soon as I was on empty I filled at a completely different, more popular Shell station, and haven't seen ANY knock whatsoever since.

But this morning as I pulled in to park at my job, I notice as soon as I was idleing my AF Learning 1 had dropped to about -17... now it's normal for me to see anywhere from -5 to -14 at idle on the MAP 93 octane tune im running, but I don't think I've ever seen it go as low as -17, this would normally make me think there's a leak somewhere, however, I just took my car to the dealership recently and they did a smoke test through everything while I was there. No leaks found of course, but I did a fair bit of reseating and tightening when the knock was present prior to them checking. Before anyone asks the MAF is clean as a whistle (but I wouldn't put my mouth on it) and I got a brand new air filter from dealership. I also just did spark plugs about 500 miles ago. So nothing should be wrong, right?

Im not sure if this has relevance to the numbers I'm seeing, but this morning is one of the first days it's been cold here (like 38 degrees F outside temp) so I am just curious, can the cold temperature effect fuel trims THAT significantly? I always knew peak boost is lower in cooler temps due to denser air, but did not learn how this could effect AFRs...

Mind you, my wideband is still dead nuts at 14.7 and hardly ever moves while idleing. Yesterday it was even colder at like 35 degrees F, but I never saw AF Learning 1 drop lower than -11.... so I'm just asking in general to the tuners out there and to the people regularly monitoring their AF Learning 1... is this normal for the FA and has anyone else experienced a low figure like I have?
Relevant info....

https://forums.nasioc.com/forums/sho....php?t=2700738

Check/log all windows of A/F Learning and see if the problem is only at idle or if it persists.
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Old 10-18-2017, 11:14 AM   #3
Co1lt45magnus
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Originally Posted by ericdet View Post
Relevant info....

https://forums.nasioc.com/forums/sho....php?t=2700738

Check/log all windows of A/F Learning and see if the problem is only at idle or if it persists.
Thanks, I did read through that whole thread this morning, strange that no solution or 100% conclusion of whether it was normal or not was ever made. The thread just died and no one ever continued it.

It seems from what most people were posting in there, that most of them are Stage 2 or have an aftermarket intake or they're modded in some way or another. For myself personally, I just have a stage 1 tune and muffler delete, nothing else.

I was just wondering if in the cold weather I should be seeing these changes, as I've only ever monitored these parameters in the warm weather. I purchased my AP in April I believe, so I've never seen my figures in a colder climate. Thought maybe it'd be nice to get a lot of people to chime in, start a discussion since these engines have been around a little longer now in the "tuning world" someone should be able to say with certainty that the DI engines are supposed to have pretty negative fuel trims at idle.
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Old 10-18-2017, 11:19 AM   #4
ericdet
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Quote:
Originally Posted by Co1lt45magnus View Post
Thanks, I did read through that whole thread this morning, strange that no solution or 100% conclusion of whether it was normal or not was ever made. The thread just died and no one ever continued it.

It seems from what most people were posting in there, that most of them are Stage 2 or have an aftermarket intake or they're modded in some way or another. For myself personally, I just have a stage 1 tune and muffler delete, nothing else.

I was just wondering if in the cold weather I should be seeing these changes, as I've only ever monitored these parameters in the warm weather. I purchased my AP in April I believe, so I've never seen my figures in a colder climate. Thought maybe it'd be nice to get a lot of people to chime in, start a discussion since these engines have been around a little longer now in the "tuning world" someone should be able to say with certainty that the DI engines are supposed to have pretty negative fuel trims at idle.
Weather shouldn't matter. IAT goes along with it in determining air mass. I've never ran an OTS map so I can't tell you what my car did. I've never seen an A/F Learn greater than -5.47/5.47 on my car through 3 different tuners.
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Old 10-18-2017, 11:49 AM   #5
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Every OTS map I've run has a wide variance, lowest I've ever seen is -13 at idle.

Both COBB and MAP OTS files give me a -5 to -10 AF learn at idle but its always pretty close to 0 once crusing.

A protune will probably sort it out.
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Old 10-18-2017, 02:31 PM   #6
Co1lt45magnus
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Default

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Originally Posted by gn4rwhals View Post
Every OTS map I've run has a wide variance, lowest I've ever seen is -13 at idle.

Both COBB and MAP OTS files give me a -5 to -10 AF learn at idle but its always pretty close to 0 once crusing.

A protune will probably sort it out.
Yeah while cruising it's always much better, had cruise control set to 70 early today and it was sitting right around a range of -0.78 to -3

It only goes extremely negative when coming to stop and idling
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Old 10-18-2017, 03:10 PM   #7
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Need context. Without an af correction at the same time it is almost irrelevant info
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Old 10-18-2017, 04:33 PM   #8
gn4rwhals
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Originally Posted by simpleJ View Post
Need context. Without an af correction at the same time it is almost irrelevant info
I'll see if I can pull an idle log later, I think I have AF correction logged.
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Old 10-21-2017, 12:20 AM   #9
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I have been running the same tune for about a year now. AF learning is always really negative at idle for me. -7 to -15 or so. However, when im driving it levels out to within a few percent and af correction is usually also within the normal variance. The only thing I notice with the MAP tune that i find odd is that every once in while while cruising, af correction will either shoot threw the roof or pull tons of timing up to +/- 25% which i don't understand but it only last a few seconds and regulates back. I noticed that this happened on the COBB tune as well so I chalk it up as normal. I am looking to get an Etune in the spring though.
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Old 10-21-2017, 01:20 AM   #10
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Quote:
Originally Posted by moarboost16 View Post
I have been running the same tune for about a year now. AF learning is always really negative at idle for me. -7 to -15 or so. However, when im driving it levels out to within a few percent and af correction is usually also within the normal variance. The only thing I notice with the MAP tune that i find odd is that every once in while while cruising, af correction will either shoot threw the roof or pull tons of timing up to +/- 25% which i don't understand but it only last a few seconds and regulates back. I noticed that this happened on the COBB tune as well so I chalk it up as normal. I am looking to get an Etune in the spring though.
Your car is removing fuel not timing, there is a big difference. Just AF Correction by itself isn't particularly useful. Correction and Learning are used in tandem, Learning is a long term correction while Correction is immediate short term corrections, also known as "fuel trims". You put both Learning and Correction together to get the correct percentage. So if you car is at -10 AF Learning and +11 AF Correction your overall correction is +1%. It's very, very easy to get a quick 20% correction with a quick blip or release of the throttle. When your car reads 14.7 and you just stepped on the gas and added 10 PSI your car goes oh **** and starts adding fuel like crazy until it can get the proper fuel tables in order. There's nothing wrong with that, it's how the car is supposed to operate.
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Old 10-21-2017, 09:08 PM   #11
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Honest mistake using the word timing instead of fuel. I did indeed mean fuel my mistake. I don’t usually see the corrections I’m talking about during quick blips or something like that. It’s usually during light throttle period usually during warm up. Afrs will easily go into the 16’s and 17’s while cruising at 50 to 60. That’s when I see the crazy high corrections and can feel significant hesitation from the engine. If I apply quite a bit of throttle it will snap out of it and regulate but go right back to the corrections until something changes and it goes back to normal operation.
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