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Thread: Lean Surge During 2200-3000 RPM Cruise

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    Default Lean Surge During 2200-3000 RPM Cruise

    Can't seem to quite figure this out. Been an issue since fire on the Terminator X. Figuring it's some sort of cam surge, but cannot quiet nail it. I have a huge spike in my Learn Table. Around 40% every time I check the learn.
    2004 5.3L
    Summit Stage 2 Turbo Cam
    True Bosch 210s using FIC2150 data, also tried 2000cc ID data which is very similar.
    Victor jr intake (I drilled a hole at the top of the elbow and solid mounted the GM 2.5 bar MAP there.)
    Single turbo on the Hooker turbo setup.
    Wideband around 12" post turbo.
    6 speed, 3.50 gears, 26" tire.

    At first I assumed it was due to deceleration being super lean, but it seems to follow if I'm cruising at 32-39 kPa it will surge from 14 AFR to 17 AFR. Tried timing in the areas of 26°, 30°, 32° etc. All the same results. Tried shutting off learning in those cells, same results. Other than these issues it runs amazing, minus the super lean decel making it very raspy. I have reset the IAC, reads around 4% hot idle. Looked through the datalogs, don't seem to see misfires or any sensor related issues, just AFR surging. They only thing it seems to follow is due to having a 1:1 regular it happens when my fuel pressure is at around 34 psi. (Base is tuned and set to 43 psi.) Next ideas I'm thinking is remove and plug the vacuum line on the regulator, and possibly try running Open Loop only. Jay

    Click image for larger version. 

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    Last edited by jay_rich; 06-07-2019 at 09:44 PM.

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