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Old 11-20-2020, 04:21 PM   #1
Scooby Newbie
Member#: 519178
Join Date: Oct 2020
Unhappy Reverted to stock airbox and AFR's are trash

2003 usdm wrx 5mt hatchback. It was running a garbage plastic k&n air intake with no tune when I bought it so I went back to stock airbox so my AFR's would go back to normal but this was not the case.

My only MOD is a grimmspeed decatted uppipe. Got a smoke test no vacuum leaks nor exhaust leaks nor CEL's. I have 2 logs one of me chilling under 3k rpms and one of me flooring it in 2nd gear. People tell me you can have a decatted uppipe with no tune so I do not understand what is going on.

I have recently changed oil, replaced AFR sensor in the exhaust manifold, cleaned my MAF, replaced both front cv's and it was recent adding the grimmspeed uppipe.

Do I need to tune it? If so what would you recommend? There is less backpressure so that would make me run rich anyway right? But my AFR correction is positive 25 meaning its running lean so I am confused. Also I do NOT have a wideband is that a necessity when looking at AFR's even with a mostly stock car.

Logs: https://drive.google.com/file/d/1nA8...ew?usp=sharing -cruisin
https://drive.google.com/file/d/1Va2...ew?usp=sharing - WOT

Also I am a noob so feel free to correct me on anything I assumed here

Last edited by Conster102; 11-20-2020 at 04:27 PM. Reason: I don't have a wideband
Conster102 is offline   Reply With Quote

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