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Injector outputs (INJ)

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Note: Injectors are not polarity sensitive, but direct them all the the same way.





Injectors over 8ohm = no resistor needed.

Injector + external resistor = ~10 ohm.

A ~4.7 ohm in series with a low impedance injector is generally a good choice.





Note: The below is only for the below peak/hold enabled ECUs.



Depending on hardware revision, max current (A) values might differ, check MTune software when online.


From the injector dropdown list, select User defined and enable peak-hold drivers, Peak and hold current is now visible.


MaxxECUs with built in peak-n-hold drivers uses a current feedback PWM system with a controlled fly back voltage for optimum dynamic control of the injector(s).

The peak-current is the current used to open the injector, after this, the hold-current is used to keep the injector open with minimal heat dissipation.


Generally 3-4A (3000-4000mA) peak and 1A (1000mA) hold current is sufficient for most injectors.

Higher values are NOT always better and to high settings can damage the injectors.

Very high flow injectors and/or fuel systems with higher fuel pressures than normal will need higher currents. Up to 5A peak and 1.5A hold can be used with for example 2430cc Siemens Deka injectors.


When using the setting "Multiple injectors per output" the current will be internally multiplied by the number of used injectors. Any number of injectors can be used per output, as long as the overall currents do not exceed 10A peak/3,5A hold.


When the Injector outputs are used for other loads than injectors the PWM current control is not used. The outputs can handle up to 10A peak/5A continuously.



Example of injector currents and voltages at 13000rpm.


(the missing events are a 2 cycle long shiftcut triggered by the blue input signal).