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Autronic Charge temp tuning

Heat soak is one of the typical problems with ECU’s and correcting the mixture based on intake and water temperatures is not easy.
To combat this problem, Autronic has a feature called Charge Temp table and is used to correct the mixture based on the intake air and water temperatures.
Table axis can be defined as in the setup and my table is below:

Below is an explanation of the method I used to tune the charge temp table. This method applies to water-cooled engines.
Goal is to keep AFR steady while intake air or coolant temperature changes by altering the charge temp value.
- Turn off any fuel correction methods like CLC, make sure additional fuel correction tables are not in use (Values should be 1 in the tables)
- Tune the mixture to your target, let’s say 14.7 at idle. Coolant 90C, IAT 20C.
- Start logging, log at minimum: IAT, water temp, charge temp, AFR
- Let the car idle to heat up the engine compartment and intake air.
- After Intake air has increased, check the log and note if the AFR got lean when IAT increased. Example log is shown below and shows how AFR goes lean when intake temp increases. Note the yellow line:

- If AFR increased, increase the value in Charge temp table and tune your fuel table again before making a new test.
- Repeat the test until AFR stays steady at your target AFR even when IAT temp increases.

Here is the finished tune, note how AFR stays at 14.7:

:

NOTE: If you are using LOAD as your fuel and ignition table axis, you can use charge temp assist feature to calculate new values to your fuel table.  If you are using throttle as axes, charge temp assist isn’t available.