Scripting a grenade

I am trying to make my grenade explode but when i throw it nothing happens. can someone please help me. my script is the one i have attached to grenade prefab

var creationTime = Time.time;
var explosionPrefab : Transform;

function Awake()
{
creationTime = Time.time;
}

function Update ()
{
if(Time.time < (creationTime-3))
{
Destroy(gameObject);
Instantiate(explosionPrefab, transform.position, Quaternion.identity);
}
}

You are checking if The current time is less than when you created it. Right now the grenade will only go off if you invent a time machine.

You need to check if Time.time is GREATER than start time PLUS (not minus, another problem you had) detonation time.

thankyou soooooo much