IMO, there are no performance gains to be had through TPS adjustments, though there can be some drivability improvements.
The TPS is locked to the throttle shaft that opens & closes the throttle plates. In side the TPS is a resistor whose value changes with the throttle opening. The ECU supplies a precision +5VDC to one end of the resistor and ground to the other end. As the throttle is turned a ‘wiper’ runs along the resistor and picks up a voltage. When the wiper is near the ground end the voltage it picks up will be very low, when the wiper is near the 5 volt end the voltage it picks up will be near maximum. At idle the throttle plates are slightly cracked so the voltage is somewhat bigger than zero. When the throttle plates are fully open the voltage will be very nearly the full 5 volts. The FSM specifies that at idle the resistance of the TPS should be 650 – 750 Ω and at full throttle it should be 5k Ω.
The ECU takes the wiper DC voltage and runs it through a converter that returns a digital value. The ECU does some simple math on the digital value and converts it into a percentage. At idle the diAG screen should show 15-17, which is 15% to 17% throttle opening. At full throttle the diAG screen should show 97 – 100 which is 97% to 100% of possible throttle opening.
The ECU sees the absolute position of the throttle plates but additionally it can calculate rate of change too. The ECU will know if you are gradually changing throttle position to maintain speed or if you just popped the throttle full open, expecting instant acceleration.
The throttle plates can’t physically be more than 100% open, if the TPS returns a value of 105% I’m sure the ECU recognizes that there is an error and simply substitutes 100%. If you were to set the TPS so that it reached 100% at 7k rpm the ECU would think the throttle plates are fully open and supply FI volume and timing expecting that there is maximum air flow. Since the throttle opening isn’t really totally open, the FI will be excessively rich.
The ‘span’, the amount of travel of the TPS is fixed, all you can do is push the span range lower or higher. If you adjust the TPS to deliver 100% at 7k rpm the idle point will be near 0%, most likely causing the engine to not idle well, if at all.
Hopefully you found something useful in all those words :sleepysmileyanim:
What's in the TPS