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Does a lean spike after shift hurt my engine?

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Old 10-10-2021 | 02:19 PM
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denElias's Avatar
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Default Does a lean spike after shift hurt my engine?

Hi guys,
I have a 1.6 turbo enige. When doing a pull, the log shows a lean spike after shifting (and resuming throttle).
Can this hurt my engine? should I try to tune this out? (by adjusting AE probably)
Maybe I have too much AE and get a missfire?

In the car I dont feel any hesitation of the engine.

Thank you in advance,

Old 10-12-2021 | 08:31 AM
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Unless you take active measures to tune this out (using AE, or EAE) you will experience this kind of spike. Just think, you snap open the throttle plate and the engine takes a big gulp of air without a corresponding big gulp of fuel - there's your lean spike until the injectors catch up. Will it hurt your engine? Probably not IMO. The duration of that spike is very short (i.e. it's a spike).

Some advice; AE by itself probably won't get rid of the spike all by itself. You might have to resort to EAE to get it under control. For me, EAE was a deep, deep rabbit hole so be prepared. I was never able to tune out lean spikes on accel (nor rich spikes on decel). I got close, but they never went completely away. If you're a perfectionist, you will pull your hair out trying to get that last little wiggle out. I've learned that sometimes "good enough" is good enough.
Old 10-12-2021 | 08:45 AM
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Thank you very much for the input.
I'm gonna try to perfect my accel pump AE settings and see where we end
Old 10-06-2022 | 08:44 AM
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Originally Posted by rwyatt365
Unless you take active measures to tune this out (using AE, or EAE) you will experience this kind of spike. Just think, you snap open the throttle plate and the engine takes a big gulp of air without a corresponding big gulp of fuel - there's your lean spike until the injectors catch up. Will it hurt your engine? Probably not IMO. The duration of that spike is very short (i.e. it's a spike).

Some advice; AE by itself probably won't get rid of the spike all by itself. You might have to resort to EAE to get it under control. For me, EAE was a deep, deep rabbit hole so be prepared. I was never able to tune out lean spikes on accel (nor rich spikes on decel). I got close, but they never went completely away. If you're a perfectionist, you will pull your hair out trying to get that last little wiggle out. I've learned that sometimes "good enough" is good enough.
@rwyatt365 I just got done reading your thread on your journey of EAE and I can only say wow. It was an exhausting read but a good read. Props to you for your determination and experiments. If I ever do decide to get involved with EAE that thread will be something I will revisit and a couple others.
Old 10-06-2022 | 11:02 AM
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Originally Posted by Hernj65
@rwyatt365 I just got done reading your thread on your journey of EAE and I can only say wow. It was an exhausting read but a good read. Props to you for your determination and experiments. If I ever do decide to get involved with EAE that thread will be something I will revisit and a couple others.
EAE is both a blessing and a curse. When/If you get it right, you are a hero. Right now, I've probably forgotten my journey to get to where I am. Glad to be of some help with this.
Old 10-06-2022 | 02:31 PM
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It is a very cluttered pic of the log. By adjusting the view and limiting the information to what pertains to what your tuning will help you when tuning one specific characteristic. The AE response to a 313.2 TPSdot is only 112 which seems a bit low. If the AFR/VE map is not well tuned, fueled a bit lean for the requirement, it can require more AE. Also the transition on the map can be a factor. In this case your most likely transitioning from the lean cruise part of the map to the in boost power area. The TPSdot is not always intuitive because it is representing something that is a squared factor. The relationship between the steady state tuning and the accel requirement is a challenge for most. Certain areas of the map can be tuned more for accel because they are never used for a fixed speed or steady state operation. .

Last edited by LeoNA; 10-07-2022 at 01:56 PM.
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