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The MS1-Extra and MS2-Extra ECUs can read from either a narrow band lambda (0-1V usually) or from the controller of a wideband lambda (0-5V usually) A wideband lambda sensor needs a controller to drive the sensor and to give an output that's suitable for the MS ECU. Most sensors are narrow band and they only tell the ECU that the mixture is rich or lean of stoichiometric (14.7 Air:Fuel Ratio). If you have bought a wideband lambda then the controller tells the ECU the whole range of AFR, so it is by far a more accurate way of tuning, especially for power.In MegaTune go to Exhaust Gas Settings or EGO Control:
Ignition Events per Step: set this to a value that would switch about 4x a second at your average cruising speed.
4 cylinder assume 3500rpm cruise set Ignition Events per Step to : 29
6 cylinder assume 2500rpm cruise set Ignition Events per Step to : 31
8 cylinder assume 2000rpm cruise set Ignition Events per Step to : 33
You can calculate your:
O2 adjustments per second = ((rpm/120) * cylinders) / ignition events per step
Please Note:
If you decide to run without a lambda sensor (either you remove it after tuning or your tuning on a rolling road without a sensor) then set the Controller Step Size to ZERO!!If using a Narrow Band sensor, these usually have 1-4 wires, the heated versions are the better ones to use. A narrow band sensor will give an output of 0.5V when the mixture is at stoichiometric (14.7AFR), this is the most efficient mixture for cruising so should be used as the EGO Switch Point in the Exhaust Gas Settings.
If you're using a Wide Band lambda sensor and controller then the ECU can correct the mixture at various loads using an AFR Target Table. These tables can be set for use in Lambda AFR Settings for MS1-Extra, in MS2-Extra they are automatically used when you tell it you have a WideBand lambda, so ensure you set the table up.
If you chose not to use the AFR table with a Wideband in MS1-Extra, then simply find out the sensors output at stoichiometric (14.7) and put this in the EGO Switch Point and ensure you select Wide Band rather than Narrow Band!!!
If your wideband sensor is programmable, e.g. the Innovates LC-1, then I recommend setting the output so it is 0-5V = 10-20AFR, this gives a good resolution over the area of the mixture you will be tuning. This is done easily in the Log Programming software of Innovates when using an LC-1. The yellow wire from the controller is output 1, so use that wire into the MS ECU and set Output1: 0V = 10AFR 5V = 20AFR
If using MS1 then set the Lambda Sensor up in the Configurator as INNOVATES_0_5_Linear -- Innovates, PLX 0-5V 10-20:1 AFR (see below for more details) this can be set for any sensor your using that has an output programmed as a linear 0-5V = 10-20AFR.
If using MS2 then select Generic Linear WB from the list and set the table Point1 0V = 10AFR and Point2 5V = 20AFR (see below for more details)
MegaTune Settings
You must change a few settings in order for the MegaTune software to be able to distinguish between what wideband sensor you are using, and therefore tell what the output voltage means. To do this use the MegaTune installer on the CD I provide or the installer on my downaloads page. You can select either a LC-1 or Techedge wideband during the install, but if your using another type of sensor or you didn't use the installer then you'll need to use the Configurator within MegaTune. To do this run MegaTune and select:
File - Configurator
Then select
Car1 - Settings.ini - Settings - Lambda Sensor
Now select your WideBand Lambda sensor from the list highlighted in RED here. Save and exit the program. The next time MegaTune is opened it will work for your lambda sensor
If you are using a wideband lambda sensor in MS2-Extra then you'll need to set the ECU up for that sensor. this is easilly done by going into MegaTune and selecting Tools - Calibrate AFR Table. With the MS ECU powered up and on-line select your wideband sensor from the list and click OK
