Tuning an Engine
This is best done using an engine or chassis dyno. It is not good practice to try and tune an engine while driving on the road. This would be dangerous to yourself and others.
Tuning Fuel and Ignition Maps
You can tune an engine by using the built-in MAP sensor, a Throttle position sensor or one of the Analog inputs as a primary load source. The tuning processes for each method will be the same. Using the internal MAP sensor to read engine load The internal Manifold Absolute Pressure sensor is a 5 bar sensor that can read pressures from –100 Kpa (full vacuum) to 200 Kpa (30 Psi). The tuning grids have a possible 40 user definable R.P.M columns and 21 user definable load rows which give the tuner 3072 individual load points. The ECU comes with pre-programmed fuel map settings at 500 R.P.M increment. These are only a starting point and can easily be changed. If this is the first time you have set-up a particular engine you should use the Fuel Trim function in the Trims section of the tuning screen to help get the engine started. Using a Throttle Position Sensor (TPS) to read engine load A throttle position sensor can be used to read engine load by detecting the position of the throttle from fully closed to fully open. This is represented as a percentage from 0 to 100 percent. The tuning grids have a possible 40 user definable R.P.M columns and 21 user definable position percentage (load) rows.
It is extremely important that a good quality TPS be used when tuning using TPS load sensing. Make sure that the TPS is a variable resistance (potentiometer) type and that it is properly calibrated (see Throttle Position Sensor Calibration for details). Ensure that the sensor reading is repeatable after calibrating.
Watch the TPS gauge on the tuning screen and make sure that the reading follows your foot movement and reaches 100% when fully pressed, and then returns back to
%. Do this a number of times to ensure that the reading returns to 0% every time.
This load source selection relies heavily on the TPS sensor, so ensure it is operating before commencing to tune.
Using fuel trims for first time engine start up It is much easier to get the engine running for the first time by using the fuel trim adjustment. This adjustment is found in the trims section of the tuning screen. If you see that the engine is difficult to start because it is too lean or too rich then you can increase or decrease the fuel delivery until the engine starts easily. Adjusting Fuel / Ignition Maps Bring the engine up to the desired R.P.M / load and press the space bar, this will position the cursor onto the R.P.M / load point that matches the actual engine R.P.M / Load. Adjust the fuel or ignition setting by the pressing the “Pg up” or “Pg dn” keys to increase or decrease the injector mS or Ignition timing until the desired value is reached. Repeat this for every load point on the tuning grid.
Stinger 4 instruction manual version 2.0