Originally Posted by drunkmunky
so these are settings for the tunerpro application???
No, the values refers to a function called Map Trace in the Nissan Datascan (Nissan Data Scan ver. 1.5
) application. In actuality, any application that performs map tracing can use those values.
This is the basis of how it works,
- The ECU reads the engine rpm via the distributor camshaft sensor. It stores this value in RAM locations 3472 and 3473.
- The ECU takes the MAF air coming in, calculates an engine load (TP) value, and stores this value in RAM locations 31B1.
- The ECU then looks up a map table stored in ROM. For example, the fuel map or ignition map table.
- It locates the row in this ROM table where the value equals the rpm value in 3472 and 3473.
- It locates the column across this ROM table to locate the previously calculated TP value in 31B1.
- The point of intersection between the TP and RPM will contain a value to use for the fuel injection; and even for the ignition timing.
- If the values for the rpm and TP does not fall squarely within the map ROM cell, then the ECU will use an interpolation routine to calculate a value that is the closest value possible.
The art of ECU tuning takes these stored ROM values inside the ECU and optimizes them for a particular engine. The default values stored in there were a trade-off for the engine requirements in terms of performance, fuel economy, and emissions.