G1/2 water sensor

I am trying to use 2 different water sensors at the same time. I used the program that is online and it worked when I used pin 2. But what do I have to change so that I can work with another pin? I changed the pin (both in hardware and software)but still it did not work. Here is the code. It continued to read only from pin 2

[code]volatile int Signal_1; //measuring the rising edges of the signal
int MeasuredFlow_1; // the converted output signal
int flowmeter_1 = 3; // Assigning pin 2 to input of flow meter 1 (input)

void rpm () //This is the function that the interupt calls
Signal_1++; //This function measures the rising and falling edge of the hall effect sensors signal
// The setup() method runs once, when the sketch starts
void setup() //
pinMode(flowmeter_1, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised,
attachInterrupt(0, rpm, RISING); //attaching the interrupt
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop ()
Signal_1 = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
MeasuredFlow_1 = (Signal_1 * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour
Serial.print (MeasuredFlow_1, DEC); //Prints the number calculated above
Serial.print (" L/hour\r\n"); //Prints “L/hour” and returns a new line