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Discussion Starter #1
Hi! New to this place so I'm not sure what forum to put it under.

Okay so, I Data logged my RS using an SCT X4 and LIVELINK because I was getting a DTS code saying I'm too lean (and also a couple codes regarding my catalyst). I can also smell it running lean sometimes. Now I can't compare the data cause I can't find anywhere that tells me what my AFR should look like under WOT.

  1. Now my car's AFR (under WOT) stays at the Stochio level (high 14 AFR) all the way up untill 5000k rpm/ 390 Absolute Load/ 10psi Boost; where it then drops down to 10.9ish AFR.
Now I can actually feel that change. Specifically when going WOT in 1st gear. It always scared me and I would immediately let off the throttle. I've also found people on this site to also experience the same sort of thing at the same rev range as I do. So is there a correlation there?

Anyways, I would've thought there would atleast be some change in AFR before near topping out but I'm definetly not sure.

So, is that how it's supposed to be? Any info or graph of your own AFR/RPM would be great, thanks!
 

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You don’t need to know the AFR. You need to find the air leak and fix it. The LTFT is what you need to log. The ECU is saying it’s lean because the LTFT is too high.
 

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AFR in 14s at WOT is super lean.

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Discussion Starter #4
You don’t need to know the AFR. You need to find the air leak and fix it. The LTFT is what you need to log. The ECU is saying it’s lean because the LTFT is too high.
Holy ****! Yeah I double checked my LTFT logs and it was using some weird Unit. So it looked completely normal with a first glance. So I just went out and did another log with a LTFT with an actual percentage unit and Holy **** I was getting damn near +30% trim.

I just glossed it over and there is no apparent leak, I'll be extensively looking for one comes tomorrow. Thanks so much for the help dude! You saved me so much time.
 

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It might help to share what mods you have, especially if this started after you did some mod dealing with the exhaust side of things.

There are a few people on here who have had to replace O2 sensors and the high pressure fuel pressure sensor to fix similar problems. Search on here for their experiences, see if your issues match theirs.
 

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Discussion Starter #6
It might help to share what mods you have, especially if this started after you did some mod dealing with the exhaust side of things.

There are a few people on here who have had to replace O2 sensors and the high pressure fuel pressure sensor to fix similar problems. Search on here for their experiences, see if your issues match theirs.
Hmm well I bought it from the dealer and it did have mods. There's the MBRP Exhaust, an aftermarket air filter, and an ETS intercooler. That's all that I can see. I don't think it was tuned. And if it was, it was probably reset at the dealer. I was already thinking of replacing the O2 sensors when I initially started having problems.

Anyways, I will scour around this site for more info. And again, thanks so much.
 

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For gasoline, you'll prob see numbers like 10-11 under WOT with a conservative tune. Higher hp tunes, I'm guessing 12.5-13.5
 

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Hi! New to this place so I'm not sure what forum to put it under.

Okay so, I Data logged my RS using an SCT X4 and LIVELINK because I was getting a DTS code saying I'm too lean (and also a couple codes regarding my catalyst). I can also smell it running lean sometimes. Now I can't compare the data cause I can't find anywhere that tells me what my AFR should look like under WOT.

  1. Now my car's AFR (under WOT) stays at the Stochio level (high 14 AFR) all the way up untill 5000k rpm/ 390 Absolute Load/ 10psi Boost; where it then drops down to 10.9ish AFR.
Now I can actually feel that change. Specifically when going WOT in 1st gear. It always scared me and I would immediately let off the throttle. I've also found people on this site to also experience the same sort of thing at the same rev range as I do. So is there a correlation there?

Anyways, I would've thought there would atleast be some change in AFR before near topping out but I'm definetly not sure.

So, is that how it's supposed to be? Any info or graph of your own AFR/RPM would be great, thanks!
Happy to post up a datalog for a 3rd gear WOT pull of a healthy tune if you like.


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