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Duramax low boost fueling

Practical Diesel Tuning

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Hello! I have been playing with low boost fueling for quite a bit now on my LBZ Duramax. I am working on making a 5 stage tune, currently trying to make the "hot" tune. I basically just slightly arched/ opening parentheses "(" shaped the torque based fuel table. When the engine was warm earlier, I do not know what to call the event, but it knocked/jumped for a couple seconds then went away, and it drove actually pretty well. The throttle was light, which is what I was trying to achieve. However, on cold starts, the truck, jumps/hard knocks a lot more than I would like. I am trying to achieve a sporty weekend throttle. Adjustments I have made are raise the torque based fueling, then trimmed the pedal to desired torque table a miniscule amount as an attempt to smooth the throttle. May I have the run down on low boost fueling, and what pointers can I be given, as well as do's and dont's? And what can I do to mitigate the cold start shenanigans and achieve the most comfortable experience as possible?

On an LBZ the fuel rate is limited with regard to airflow by the mixture limit table (lambda limit) via airflow rated reported from the MAF. Boost doesn't directly play into the calculation.

Base on what you've told me and without seeing the tune it sounds like you may have populated fuel or torque into a zero TPS row or a zero torque row or possibly ramped fuel/torque in too quickly off idle. I would shift your adjustment one or two rows down the table and see if it clears up.

Hope this helps,

Nick

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