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Discussion Starter #3
It does both, sometimes about +32 and about -29 and it seems to be happening as soon as the clutch goes in under light to medium acceleration it just kind of hops up and comes down very quickly
 

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Looks like you are describing short term fuel trim. How does the long term fuel trim look?

My LTFT shot up to +25 at idle and low load when the fuel pressure regulator vacuum hose popped off.
 

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Discussion Starter #5 (Edited)
Looks like you are describing short term fuel trim. How does the long term fuel trim look?

My LTFT shot up to +25 at idle and low load when the fuel pressure regulator vacuum hose popped off.
How would i go about looking at LTFT? Would that be af learn 1? If so that stays at 2.34 on idle and 0 at wot
 

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LTFT is AF Learning, STFT is AF Correction.

AF Learning is what you want to keep an eye on. It should ideally be in the +/-5% range.

Your AF Learn 1 looks good.
 

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Discussion Starter #8
So if my af learn 1 is good, and my af correction 1 is bad, should i continue to be concerned? I will be replacing the front o2 sensor in an attempt to fix the issue. And might have to replace the rear o2 sensor because it was white from running lean when i had a leak.
 

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Discussion Starter #9 (Edited)
Replaced front o2 sensor still causing issue. Any ideas? I think when it jumps past positive and negative 25 its between shifts mostly first to second and it under light acceleration

@2bfi yes my car is doing that as well but my fuel pressure regulator line is connected. Would it maybe be my fuel pump?
 

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I just checked my A/F Correction it ranges from +/-16.

I think your readings are fine as long as A/F Learning is good. Keep an eye too on FBKC & FLKC to be sure.
 

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Discussion Starter #11 (Edited)
My af learn is at 2.34 and at 0.00 at wot, and my feedback knock rarely has a value and if so it?s like -1.40. My fineknock is usually the same.

I?m probably going to be going to RevWorks(local Subaru shop) to get a smoke test just to be sure.
 

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Discussion Starter #12
Smoke test came out good. Drove Mikey botti my tuner to the airport and he said that their is a fuel pump issue. I have an AEM 320, do they always go out quickly? Ive only had it for maybe 6000 miles..
 

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It is completely normal for Correction to swing +-25.

It is AF Learn (Long term fuel trims) that you should be looking at!

THere is nothing wrong with your car.
 

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back from the dead, sorry to threadjack not really but to add on.
OP, you probably haven't logged on since...but did you ever replace the pump? And so, did it better your readings?

This threads has the same questions, concerns and trail i have, but cant find a definitive answer.

Did a few serious of pulls, popped a CEL. p0171, p2196 (Extreme lean conditions/front o2 error)

Now the wideband at cruise sits between low 10s.
Before typically when cruising, it sits at 15.
When at WOT is should be at 11s

AF Correction 1 is off the charts.
Now at cruise sits only at 25, letting go the gas then it drops 0, as theres no in between, either 0 or 25
Before it would sit close to the zero range and when it does the wideband would read 15 at cruise

AF Sense 1
Now at cruise sits high at 20s
Before it would be around the 14s at cruise

AF Learn 1
It was reading upwards of 10s when i was cruising, but after i reflashed the map again it now sits at 2.34 at cruise but 5s at idle.

AF Learn A -D were either 0-8

Feedback Knock, Learn Knock, DAM are normal the first time around.

So it looks like when "now" the wideband reads rich(10s) then the AF corr 1 reads 25 and AF sens 1 reads 20
As in before wideband reads 15, AF Corr 1 reads close to 0s, AF sens 1 reads <14s

Checked all lines, and hoses as no leaks. I replaced the front o2, which was pure faded white, almost seemed like it had a crack but wiped it and just smoothed out. Fixed the CELs and the readings went back to how it was "before"

Next day i WOT a few times and noticed my readings are how the "Now" reads. I have a feeling if i were to WOT a few more times at this rate then the holy CEL will appear.

DAM dropped to .85, i decided to flash the same back back on just as a t/sing method. Had the batter out for a few hours and for some reason i just wanted to make sure the ECU didnt reset itself completely..Though i think it shouldn't reflash back to stock without the AP.

I too also have a AEM 320lph w/5k miles which is the ironic part with OP.

Could it be possibly that my front o2 cant handle my build?
Is the tune it self causing this issue?
Should i try to WOT and see if it holds peak and anticipate a CEL?
Am i running rich/lean? My wideband is reading rich vs the CEL before claims extreme lean?
I'm honestly was hoping to see the learn hit 14 so i know theres a vacuum leak somewhere but other then that, i'm out of ideas other then taking a look at the o2 again?

I emailed the shop but didn't get the answers i was really looking for.
Tried calling them but left a voicemail, i feel like since i'm out of their hands they almost just don't care. Or they're just really busy...took them 3 emails before getting a reply.

My commute to work is about an hour one way, just worried if im really running "Extreme lean" that its going to cause damage


thanks in advance
 

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AF Sense 1
Now at cruise sits high at 20s
Before it would be around the 14s at cruise . .


My commute to work is about an hour one way, just worried if im really running "Extreme lean" that its going to cause damage
I would not drive it.

I'd replace the MAF - and check fuel pressure - and then be partially stumped . . .
 

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I would not drive it.



I'd replace the MAF - and check fuel pressure - and then be partially stumped . . .

Also forgot to mention, if it matters I’m running a speed density tune. Full bolt ons, upgraded piping etc.

so this morning while cruising home from work, the readings were normal. I decided to data log and hit WOT then bam. The 0171 and 2196 appeared. Then the weird readings went again. As stupid as this sounds, I gave it hard throttle and the readings were normal again. Intermittently the readings would go weird. I throttle it again then the readings go normal.

The CEL reads extreme lean but the wideband and correction read rich. I don’t know what to believe..did tons of research to determine but everyone says not to worry about correction but just the learning, but the correction is off...must mean something.

I recall the tuner had issues with the MAF, I think replaced it? Can’t remember but end up doing a SD tune..

Going to tighten all the hoses, lines, grounds just to double check. I have a AEM Fuel pressure regulator with a gauge so I’ll take a look at that? ( if that’s what you’re referencing to?) just gotta figure out what’s a normal reading lol.

So I have two logs, one before the CEL that has triggered it. Then one when the readings seemed normal with the CEL

Readings below as reference to normal vs weird.
So normal.
Wideband cruise. 15
Wideband WOT. 11
AF Correction 1. Cruise. Close to 0
AF Sense 1. Cruise 14.

Weird.
Wideband cruise. 10
Wideband WOT. 11
AF Correction 1 cruise. 25
AF Sense 1. Cruise 20


Sent from my iPhone using Tapatalk
 

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Don't do a wide open pull if it's "extreme lean" that's a recipe for bad news.
I pulled extreme lean codes and had a dirty MAF to blame. Since your dam dropped and you're getting more issues I'd r2 the MAF sensor like the previous poster suggested


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Also forgot to mention, if it matters I’m running a speed density tune. Full bolt ons, upgraded piping etc.

I recall the tuner had issues with the MAF, I think replaced it? Can’t remember but end up doing a SD tune..
SD only or Hybrid? If SD only then MAF not used, perhaps not present. Hybrid? I'd replace MAF. It's active at cruise.

Going to tighten all the hoses, lines, grounds just to double check. I have a AEM Fuel pressure regulator with a gauge so I’ll take a look at that? ( if that’s what you’re referencing to?) just gotta figure out what’s a normal reading lol.
Yes but what matters is that it is set correctly (normally at 43.5) with no vacuum and tracks manifold pressure.
 

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Yes, hybrid so still running the MAF

Does any brand matter? Like Denso from a local auto parts shop? Or stick to OEM from the dealer?


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