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Navigation: MTune Settings > Limits

Lean power cut

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Lean power cut


Lean power cut enable

Built in safety function to prevent engine from running lean.

RPM, boost pressure (MAP), TPS and lambda values can be changed to achieve the desired effect on cut level.

Use this function with precautions as it might be difficult for a driver to handle loss of power during high speed racing.


Note: Requires a wide band sensor connected to MaxxECU



Activation conditions



Specifies the MAP value engine must exceed in order to activate this function.



Specifies the minimum RPM to activate this function.



Specifies the minimum TPS to activate this function.


lambda threshold


Threshold source

Fixed value - A fixed value (max lambda) which specifies the highest lambda, does not pay attention to the lambda target table at all.

Lambda table - The cut threshold (max lambda deviation) from the lambda target table + this value. (if the lambda is to far away from the lambda target table, cut the engine to prevent damage).

Note: Lambda target table+deviation = cut threshold.



soft cut(misfire)


Soft cut enable

Enable or disable the soft cut function.

When enabled MaxxECU will "soft cut" (misfire) before completely shut down the engine.


Time before soft cut

Time before soft cut is enabled.

Should be lower than Time before cut below because lambda value needs time to stabilize.

Recommended value is 0.5 sec.



Total power cut


Time before cut

Specifies the time frame before MaxxECU will cut the engine completely.

Do not use to low values because lambda needs time to stabilize.

Recommended values: 0.5 - 1.0 sec.





Reactivation mode

Below fixed TPS

Below fixed TPS or throttle change %


reactivate below TPS

Specifies the TPS opening to reactivate this safety function.


reactivate TPS delta

% change in TPS (from where the error occurred) to reactivate this function.





Lean power cut with a fixed value


In the above example the lean power function will start to misfire after 0.4 seconds when boost is more than 0.8bar (180kPa), engine rpm is more than 4000 RPM, Throttle position is over 80% and the lambda value is leaner than lambda 0.92. If driver has not released throttle after 1 second, total power cut occurs.



Lean power cut using the lambda target table (preferable use this)


1. Set up your target lambda in tuning --> lambda table. (The marked area where we are about to pay some attention in this example).




2. Head over to Limits --> Lean power cut. Enable the function and set your activation conditions to suit your need.



3. Change the threshold source to lambda table and enter a max lambda deviation value to suit your need.

In the above example, our lambda target (marked cells in step 1 is lambda 0.84). The lean power cut function will activate when the lambda reads higher than 0.88 in this example.