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M1 fuel composition input

MoTeC M1 Software Tutorial

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Hi guys, I want to use Fuel Composition to control boost, timing, injector duty, etc when my input is put to ground or 12V (would prefer GND), since this input already activate a secondary fuel pump only for Ethanol on a secondary fuel rail

on the package used i'm not use which input I should use for this

thanks for all inputs :)



Are you trying to use a fuel composition sensor (ie, one that reports the alcohol content %), to allow flex fuel operation, or are you using a switch to allow switching between two different fuels, so say gasoline and methanol?

I use a switch to say the ECU that I change fuel

An Analog Temp input (such as 5 or 6 shown above) is a good input for a switch to ground.

The way Secondary Fuel is used with the standard GPxx packages is the Secondary Injectors are assumed to run on the secondary fuel, and the Fuel Injection Secondary Contribution Main table is used to control how much primary fuel and secondary fuel are used at any given RPM and Manifold Pressure.

In order to have a manual switch modify the Fuel Injection Secondary Contribution Table (ie, add an axis for a "Fuel Selection Switch"), you would need to have a custom package developed using M1 Build. It would probably be best to have MoTeC do this for you since they could start with the latest project sources. If you are using the same injector for both fuels, you will probably need to wire each injector to two outputs, one configured as primary and one as secondary.

Direct Injection is pump gaz (stock fuel tank)

Port injection is Ethanol (secondary fuel cel)

So yes the Fuel injection secondary contribution Main table is used already ajusted for both injectors sets. I adjust them already.

I want The manual switch will only activate Flex fuel (Alternative fuel). With that when the input is ON, the Alternative fuel will know that we allow boost increase (Alternative fuel already control the secondary fuel pump, and work actually like that)

Once flex fuel (Alternative fuel) is ON, the Flex fuel allow boost limit, timing, fuel ajustements.


The Alternative Fuel Mode is either "Flex Fuel" or "Secondary Fuel". You don't get to change this dynamically.

However, it seems like you should just configure a driver switch and use that for the "Engine Boost Limit Switch", "Fuel Mixture Aim Main Switch" or "Fuel Mixture Aim Trim", "Ignition Timing Main".

I think you are making a mistake trying to configure a switch to provide the Fuel Composition Sensor value, since this won't be used correctly unless the Alternative Fuel Mode is Flex Fuel. Your setup above since you just have a switch, I would not try to use the digital decode, just the manual calibration.

Yes Flex fuel mode allow more flexibility, this is what I have in mind to use.

a single switch without Flex fuel don't seem to allow me to control the secondary fuel pump.

yes the goal is to use Flex Fuel but with only 2 values

-when input is ground is 100% ethanol, so allow more than 200kpa so the Fuel secondary contribution will drive the Direct and Port injection.

-when input is not ground it keep Boost bellow 200kpa, so Secondary Fuel secondary contribution keep only Direct Injection in operation.

So this could work, I just need to find where to configure pin control treshhold, etc

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You don't set a threshold voltage, you use the voltage in the Translation table. Make anything 0 - 0.5v be 85% alcohol, and anything 0.6v and greater to be your normal fuel alcohol content (0-10% typically).