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Navigation: MTune Settings > Fuel

Fuel inj general

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General fuel injection settings

 

Injection method

Specifies injection mode.

Sequential is always preferable, but requires a fitted cam trigger sensor.

Simultaneous - All injectors are opened at the same time once every 720 degree.

Group - Injectors are opened every 360degrees, but only half of them.

Sequential 360 (4-stroke) - Injectors are opened individually on each cylinder every 360 degrees. 50% fuel load each injection event.

Sequential 360 (2-stroke/wankel) - Injectors are opened individually on each cylinder every 180 degrees. Full fuel load each injection event.

Sequential 720 - Injectors are opened individually on each cylinder once per engine revolution. If injection/ignition is in the wrong engine cycle, change Cam signal position in Inputs --> Trigger, Trigger decoder.

Sequential 720 without sYNC - Injects fuel every 2 crankshaft revolutions. Used with trigger systems without cam sync. As the ECU doesn't know if the cylinder is in the intake or exhaust cycle the fuel may be injected during either one. This is determined each time the engine is started, and will always be the same when engine is running.

Manual injection distribution (advanced) - See manual injection distribution, output entry method below.

 

Fuel stoich AFR

Specifies fuel type used on engine.

Note: Can be set to Custom setting, see example below.

 

Multiply lambda

Specifies if VE should be calculated by using the  Lambda target table.

Note: For MaxxECU to present "real" VE values, this must be checked.

 

Use MAP-sensor

Specifies if MAP sensor should be used for fuel calculations. <-- recommended.

Disable where TPS is selected as main load axis and MAP readings are unstable because of wild cams and/or intakes.

Note: Regardless of your axis source, values in ex the main VE table, the MAP-sensor data is used in the VE calculations when use map-sensor = enabled.

 

Staged injection

Enable/disable the use of staged injection functionality.

 

 

Injector settings

 

Injector

Specifies installed injector type.

Note: If your injector is missing, please use "User defined" and enter correct values.

 

Peak-Hold drivers

Peak and Hold drivers MUST be enabled for low impedance(below 8 ohms) injectors, and disabled with high impedance injectors (saturated).

 

Peak current

Specifies "peak" current which opens the injector.

3000mA = 3A which is default and used by most injectors.

Current above 5A per output is only allowed with 2 injectors per output.

Note: MaxxECU rev6+ and higher supports higher peak current, up to 8A.

 

Hold current

Specifies hold-current for injector.

1000mA = 1A works for most injectors.

 

Injectors per output

Adjusts the injector drivers for the load.

MaxxECU PRO, RACE and V1 (rev7+) can use max 2 Peak-and-Hold injectors per output.

All MaxxECUs can use max 3 high resistance injectors per output.

 

Injectors per cylinder

Adjusts the fuel calculations to account for the fuel flow per cylinder.

 

 

Injector flow settings

 

injector flow tracking

Specifies how MaxxECU "tracks" the fuel flow at different pressures.

Fixed flow with default pressure compensation - The fuel flow at different pressures is calculated using a default pressure compensation.

flow/pressure list - The fuel flow at different pressures is using the injector flow table.

 

Injector flow

Specifies injector flow in cc/min at 3bar fuel pressure.

 

Fuel pressure tracking

Fixed value - Specifies base fuel pressure. Used to adjust pre-defined injector flow based on a theoretical curve. 3 bar is a recommended value to use since this is default for most injectors when flow tested from manufacturer.

fuel pressure sensor 1/2 tracking - Use a fuel pressure sensor to be used for flow calculations. RealTime Data values are also visible which can be used in the warning system,

Note: fuel pressure deviation tracking can be done without this enabled here.

 

Fuel pressure

The specified fuel pressure when the above fuel pressure tracking is set to fixed value.

 

 

Injector dead time settings

 

Dead time entry method

Specifies the dead time entry method, List for simple mode and Table for the advanced users.

list (voltage dependant) - Simple mode using a list with the battery voltage as axis.

table (voltage + fuel pressure dependant) - Uses a table for the dead times.

 

Injector dead time

Injector dead time at different voltages. "Dead time" is the amount of time it takes for the injector to transition from closed to open.

 

Pulsewidth adder

Injectors become Non-Linear at very low pulsewidth. This table allows you to compensate for this. These values can be supplied by the injector manufacturer.

 

 

Injection even angle

 

angle reference

The injection angle can refer to degrees before TDC of the ignition phase or degrees after TDC  of the ignition phase.

 

event edge

The point on the injection event the injection angle refers to.

 

Injection angle table

Specifies the injection angle for each cylinder. Affects mostly idle and the low RPM band.

 

 

 

Examples

 

Custom fuel stoich AFR

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You can even create your own custom stoichiometric ratio based on any X or Y axis, in the above example we have configured a switch wired to the digital input 1, which can be used to switch between petrol or E85 VE calculations.