help with stepper motor code issue?

ok, i have a program that controls a pair of stepper motors.

this code works fine:

#include <Stepper.h>

// change this to the number of steps on your motor
#define STEPS 200

// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepperA(STEPS, 10, 11, 12, 13);
Stepper stepperB(STEPS, 1, 2, 3, 4);

//for reverse
//Stepper stepperA(STEPS, 13, 12, 11, 10);
//Stepper stepperB(STEPS, 4, 3, 2, 1);



//25 revolutions = 5ml
//5 revolutions = 1ml
//1 revolution (200 steps) = 0.2ml


void setup()
{
  // set the speed of the motor to () RPMs
  stepperA.setSpeed(30);
  stepperB.setSpeed(30);
}

void loop()
{

  stepperA.step(200);
  delay(1);
  stepperB.step(200);
  delay(1);

}

but when I run THIS code, the A stepper motor works, but the B stepper just vibrates, it doesn’t turn.

#include <Stepper.h>

// change this to the number of steps on your motor
#define STEPS 200

// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepperA(STEPS, 10, 11, 12, 13);
Stepper stepperB(STEPS, 1, 2, 3, 4);

//for reverse remove comments and comment out above
//Stepper stepperA(STEPS, 13, 12, 11, 10);
//Stepper stepperB(STEPS, 4, 3, 2, 1);



//25 revolutions = 5ml
//5 revolutions = 1ml
//1 revolution (200 steps) = 0.2ml

long timewillbe, timeis, stepsperminuteA, stepsperminuteB;
int rolloverswas, rolloversis;
void setup()
{
  //Serial.begin(9600);
  // set the speed of the motor to () RPMs
  stepperA.setSpeed(30);
  stepperB.setSpeed(30);
  timeis=0;
  timewillbe=1000;
  
  //////////////////////////////////////////
  //get steps per minute from spreadsheet.  
  //20ml/day = 14 steps/minute
  //max = 6000 total (sum of steppers)at 30rpm
  ////////////////////////////////////////////////////////////////
  stepsperminuteA=400;
  stepsperminuteB=400;
  /////////////////////////////////////////////////////////////////

}

void loop()
{
  timeis=millis();
  rolloverswas=millisRollover();
  //Serial.println(timewillbe);   


if (timeis>timewillbe)
{
  timewillbe=millis()+60000;
  rolloversis=millisRollover();
  if (rolloversis>rolloverswas)
  {timewillbe=60000;
  }
  stepperA.step(stepsperminuteA);
  //delay(1);
  stepperB.step(stepsperminuteB);
  //delay(1);
  
}
//delay(1);
}


int millisRollover() {
  // get the current millis() value for how long the microcontroller has been running
  //
  // To avoid any possiblity of missing the rollover, we use a boolean toggle that gets flipped
  //   off any time during the first half of the total millis period and
  //   then on during the second half of the total millis period.
  // This would work even if the function were only run once every 4.5 hours, though typically,
  //   the function should be called as frequently as possible to capture the actual moment of rollover.
  // The rollover counter is good for over 35 years of runtime. --Rob Faludi http://rob.faludi.com
  //
  static int numRollovers=0; // variable that permanently holds the number of rollovers since startup
  static boolean readyToRoll = false; // tracks whether we've made it halfway to rollover
  unsigned long now = millis(); // the time right now
  unsigned long halfwayMillis = 17179868; // this is halfway to the max millis value (17179868)

  if (now > halfwayMillis) { // as long as the value is greater than halfway to the max
    readyToRoll = true; // you are ready to roll over
  }

  if (readyToRoll == true && now < halfwayMillis) {
    // if we've previously made it to halfway
    // and the current millis() value is now _less_ than the halfway mark
    // then we have rolled over
    numRollovers = numRollovers++; // add one to the count the number of rollovers
    readyToRoll = false; // we're no longer past halfway
  } 
  return numRollovers;
}

anybody have any idea why this might be happening? It’s driving me nuts! Thanks!

turns out it was a conflict with pin1 and the serial communication. Moved the stepper from pins 1,2,3,4 to 2,3,4,5 and it seems to be working fine.