yeild not work my unity 4.6 but on unity 5 or other version working correctly!!!!!!!

Hello my freinds

on this code , yeild not work in my unity 4.6 but on unity 5 or other version working correctly!!!

using UnityEngine;
using System.Collections;

public class PreloadSceneProgressBar : MonoBehaviour {
void Update() {

	if(Input.GetButtonDown("Fire")){
		print ("Fire");
		StartCoroutine(OutOfAmmo());
	
	}

}

IEnumerator OutOfAmmo()
{

	yield return new WaitForSeconds(3);

	print ("Test");
}

}

after yield commond not work! (on unity 5 or other version working correctly)!

please help me

If you’re not getting any error messages, it could be that your TimeScale is set to zero. Do another print statement right before the yield and see if the Coroutine gets started. If so, it might be that you’ve set TimeScale somewhere else (pausing game etc…).