RPM-testing point

As we all know we install a throttle body in the middle of the pipe, the throttle body system as a piece of butterfly that we can control by the cable which connected to the throttle body of the 1UZ engine. The reason of why we still put the throttle position sensor (TPS) on is that we do not know how much angles of the butterfly moved. The TPS sensor we used is from a TOYOTA 4AFE engine throttle body, it has 4 PIN in side, and they are +5 volts (positive), ground (negative), signal output, and reference. At the first step we try to set up the +5v positive power and ground, then we used themultimeter test the signal output, but when we prepared everything it was hard to get the reading from the multimeter, so we give up this idea. In the next step we try to use the multimeter test the resistance of the TPS sensor. We try to find the positive and negative first, the resistance between positive and negative is 4.24KΩ, next step we used an idea it called "method of exclusion". To connect one of the wire (positive or negative we do not know), other side connect to one the rest 2 PINS, if the reading is infinity which means the pin is the reference, we can leave it alone, if have the reading and when move the throttle body the reading change at the same time which means this PIN should be signal output. When it connects the positive and signal output and move the throttle body from closed (idle) to fully open, the reading is from 1.58KΩ ～3.89KΩ. The Revolutions Per/ Minute (RPM) we can test by the multimeter as well, to select the RPM gear and find out the tachometer transmitter, our supervisor show us where it is, as you can see in the photo