Fuel trim concern with new intake

[503Si]

I recently got a new intake on my si (major, reputable brand, not injen) and have been having crazy fuel trim issues. Im on ktuner basemap 19.5/23psi tune. No changes to the maf scale have been done and between shifts my stft1 pops up to -25%. At idle it varies from - 7 to - 15% and my long terms are always at - 10% to now up to - 18%. AFRs seem fine but i just have to fix this running rich issue. Does anybody know how to adjust the maf scale to help me fix this? Id really appreciate it.

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[LightX]

27Won has a blog about it. I would change the intake back to stock to see if it runs normal to scale down what's causing the issues.
https://www.27won.com/blog/yeah-but-what-are-your-fuel-trims

• Leaking fuel injector
• restricted air flow via dirty filter or collapsed intake tract
• excessive fuel pressure
• EVAP system fault
• false reading from bad sensors (MAF/O2)

 

[503Si]

27Won has a blog about it. I would change the intake back to stock to see if it runs normal to scale down what's causing the issues.
https://www.27won.com/blog/yeah-but-what-are-your-fuel-trims

• Leaking fuel injector
• restricted air flow via dirty filter or collapsed intake tract
• excessive fuel pressure
• EVAP system fault
• false reading from bad sensors (MAF/O2)

Right i know that all those things can cause you to run rich but, but all things were perfect before the intake install so narrowing down the issue and having it be a new car so too early for most of these things to apply, it has to be the intake housing being slightly smaller than stock which ive read on here after posting. This is most likely the culprit. Thank you for the reply, but itlooks like tuning is the only way to fix these fuel trims unfortunately.

 

[Acraig3]

Right i know that all those things can cause you to run rich but, but all things were perfect before the intake install so narrowing down the issue and having it be a new car so too early for most of these things to apply, it has to be the intake housing being slightly smaller than stock which ive read on here after posting. This is most likely the culprit. Thank you for the reply, but itlooks like tuning is the only way to fix these fuel trims unfortunately.

I bought a no name intake and had trims like this (granted I am on e85 with no flex fuel sensor). I took my car to PFI in Colorado to have them tune it for the intake. We were talking and there are a lot of characteristics that change with a new intake.

-Flow
- turbulence
-Piping length
-Filter size
-Maf housing

The list goes on. It is best to either learn how to tune your MAF sensor properly or to get it tuned from a reputable tuner.

My MAF scaling looks much different then stock now that it has been tuned for the intake.

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