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Main Fuel map Tuning in MilliSeconds

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Hi Andre,

I need your help please regarding tuning the main fuel map in millisecond.

This might be a stupid question but in fact I am going over the road tuning course again and you mentioned something about main fuel map tuning in millisecond that it depends on the injector's size, base injector pulse width and VE of the engine. Does this mean that I will need to go back to the fundamentals course for equations or is there another easier way for tuning while on road?

Can you please guide me if you mentioned this in any other course as all I remember from the dyno and road tuning courses is that you used the VE table for tuning the main fuel map.

I attached a sample of the main fuel map that came with the DTA 100S ECU.The setting doesn't change to VE table and I am stuck and need your help and advice.

Thank you

Attached Files

Hi Andre,

Just a note that this map is defaulted in the DTA S100 and it is not for our application (M54b25). It is for another M3 vehicle.

I need your guidance on how to tune this.


Tuning in VE or millisecond work exactly the same way. Increase the value to go richer and decrease it to go leaner.

It's just two different way to display the same thing, at the end the ECU always control the injectors with a pulse with in milliseconds, the VE fuel map just do the math for you based on the injectors setup.

(With a millisecond based fuel map, if you change the injectors you will have to change all the values in the map. In the VE you only change the injector setup in the ECU)

Thanks for the reply. I thought of trying to increase or decrease the number according to the target AFR table but I though t there might be something different to calculate.

Appreciated :)

Hi mn_600, Ludo86 is right - It doesn't really matter if the fuel table is in milliseconds or VE values. All of the same principles apply and you can calculate a correction factor to apply to the current ms pulse width using the calculation:

Measured AFR / Desired AFR = Correction factor.

Multiply your current ms pulse width by the correction factor and you should quickly achieve your target.

The actual ms pusle width you require will depend on the size of the injector and the engine's fuel requirements.

We usually reply within 12hrs (often sooner)

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