If you plan to run a turbo/supercharger, or if you are using a stock plenum, then it would be wise to use MAP (Manifold Absolute Pressure) for primary load (in the Injection Driver settings before), and as a result, it is important to install and calibrate a MAP sensor. This is known as 'Speed Density' tuning.


For naturally aspirated set-ups, such as throttle bodies, you may wish to use TPS for load (a system called ‘Alpha-N’ fuelling) and as a result you may not want to even install a MAP sensor. In this case, it is important to set the MAP HRT to always read 100KPa - as shown in the above image, by setting the entire tables ‘MAP’ column to 100. This means the fuelling algorithm will not be affected by MAP readings.


If you're using a MAP sensor, then it should be calibrated. Most MAP sensors include a data sheet, that illustrate their voltage output based on the pressure they are exposed to. Below is an excerpt from a MAP sensors datasheet from the web - note these numbers will vary dependant on the sensor, and that they usually specify the pressures in ABSOLUTE terms, that is, 0 being a perfect vacuum, approx 100KPa being atmospheric air pressure at seal level (or 1 Bar), 200Kpa representing 1 Bar of Boost (i.e 1 Bar above atmospheric), and so on.



We can see from the table that the the low pressure (40 kPa) Vout “Average” is 0.631v, and the highest pressure (304 kPa) Vout is 4.914v. We could also work out the other rows, but as most sensors are linear, there really is not much need to.


First, we assume you have selected the correct Analog input channel that you have wired the MAP Sensors signal wire into, and set it to "MAP Raw" in the Analog Input settings driver.


If you bring up MAP Raw DRO in MEITE on any tab, you should see the voltage read from the MAP sensor. By sucking or blowing into the MAP sensors vacuum port, you should see the MAP Raw DRO voltage change in MEITE. If it does not, you either have either an assignment issue or a wiring issue. The DROs and HRTs are already set in the default tab named "Sensor Cals."


Be SURE you have first set MEITE units to work and display in VOLTS. (This is the default).


The next step is to enter this data into the MAP HRT table via the following process: (open it from the tree view under HRTs if needed).


  1. In the Top Left box of the MAP HRT table, double click it, and type 0.631, press enter.
  2. In the Top RIGHT box of the MAP HRT table, enter 40, press enter.
  3. In the second row, on the left, enter 4.914, press enter.
  4. In the second row, on the right, enter 304, press enter
  5. We don't want the rest of the table to be used, so in all other boxes on the left, enter 5, and in all other boxes on the right, enter the highest number the map sensor can read, which is 304. That means even if the sensors voltage somehow goes over its maximum, it will still read 304 kPa.
  6. Click the red ‘Save’ icon in the top right of the MAP HRT window. The window will have a green border to signify the data has been sent to the ECU and stored.


The MAP HRT table will now look like this:


You should see approximately 98-101 kPa with the sensor reading atmospheric pressure at sea level, decreasing as you go up in altitude (most of the UK for example shows approx 98 kPa), Colorado in the US shows 90 kPa, and so on. You can also test by blowing into the MAP sensor, and watching the yellow cross-hairs moving, showing you the RAW input, and the resultant pressure output.


Note that Plug-In variants of our ECUs will typically use an on-board 250 or 400 kPa sensor, and the base-maps already have this configured correctly.