Lean after changing injectors

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Aug 14, 2019 | 11:29 PM

chronos

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Joined: Sep 2015

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From: Abbotsford

Lean after changing injectors

I installed a set of Bosch 24# injectors from FIC and my LT1 feels way better! The 'lazy' feeling it had before is gone and the throttle response is instant. Right now I am running a stock tune as my motor is stock except for 1.6 rockers and a cat-back. However, datalogging shows that now it's running lean almost all the time whereas before my BLMs were at 128.
I tried increasing the injector offset but have no idea what the proper values should be, I finally found some reasonable looking ones on TGO and that helped get the BLMs mostly to 128 but at idle/decel it was super rich as BLMs were at 106-110. I emailed FIC asking about changing the injector offsets and they say it's not needed.

So now I'm confused how to proceed. Should I adjust the injector offset again, maybe start adding like 10% and see if I can find a sweet spot? Or should I leave the injectors alone and start increasing the VE and MAF tables.
Since the only thing that changed is the injectors, it seems logical that is what needs adjusting. Does anyone have an offset table to share?

I have attached datalogs from $EEHack and screenshots from Trimalyzer.

Thanks for any pointers!

Attached Files

Datalogs.zip (1.65 MB, 2 views)

Aug 15, 2019 | 07:30 AM

moehorsepower

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From: Texas

Change your IFE to 22 lb and see how it does, Ive had to do this sometimes, probably due to mass production and tolerances of the injectors.

Aug 17, 2019 | 08:53 PM

chronos

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Joined: Sep 2015

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From: Abbotsford

So I did a combination of increasing the injector offset 25% across the board and changing the flow rate from 24 to 23. Now it seems about close, just a bit rich. Going to play around with it a bit more.
I've also noticed that I sometimes get knock when letting off the throttle, for example at 4800 rpm, going from 100% TPS, 96.7 MAP, 30o timing (7o KR), to 0% TPS, 15.5 MAP, and 40o timing (0o KR), produces 800 knock counts. Is this normal or is there something I should adjust? I'm not sure where it's getting 40o timing from when I don't see that in my main spark tables or closed TPS spark table.

Nov 11, 2019 | 12:33 AM

chronos

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Staging Lane

Joined: Sep 2015

Posts: 59

Likes: 3

From: Abbotsford

Thanks for the tips. After a lot of tinkering and running through Trim Analyzer, I've almost got the SD portion perfect! I just uploaded an updated tune tonight and that should get it really close to 0.
I've noticed that the car feels a lot better once I disconnected the MAF, which is weird because with the MAF connected the BLMs weren't that far off. I'm thinking my MAF might be dirty and need cleaning or something.

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