Accels Instead of Jumping?

I have this issue now for days and it is driving me crazy…
Using a very simple Charactercontroller with this snippet:

using UnityEngine;
using System.Collections;

public class FPS : MonoBehaviour {

	public float speed = 20.0f;
	public float jumpSpeed = 10.0f;
	public float gravity = 25.0f;
	public float mouseSensitivity = 5f;
	public float upDownRange = 45f;
	private Vector3 moveDirection =;
	private bool grounded = false;
	private float verticalRotation = 0f;
	void Update () {		
		transform.Rotate (0, Input.GetAxis ("Mouse X") * mouseSensitivity, 0);
		verticalRotation -= Input.GetAxis ("Mouse Y") * mouseSensitivity;
		verticalRotation = Mathf.Clamp (verticalRotation, -upDownRange, upDownRange);
		Camera.main.transform.localRotation = Quaternion.Euler (verticalRotation, 0, 0);
	void FixedUpdate() {
		if (grounded) {
			moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
			moveDirection = transform.TransformDirection(moveDirection);
			moveDirection *= speed;
			if (Input.GetButton ("Jump")) {
				moveDirection.y = jumpSpeed;
		moveDirection.y -= gravity * Time.deltaTime;
		CharacterController controller = GetComponent<CharacterController>();
		CollisionFlags flags = controller.Move(moveDirection * Time.deltaTime);
		grounded = (flags & CollisionFlags.CollidedBelow) != 0;
		if (transform.position.y < 0) {
			transform.position = new Vector3 (transform.position.x, 256, transform.position.z);

But instead of a nice jump, the char only jumps when standing still - when moving around the char gets boosted into the direction it is heading and only going up when it hits a wall ?? I tried EVERYTHING millions of different approaches but the outcome is the same.

To test this just:

  • make a scene, add a plane
  • add a cube or something
  • add charactercontroller to the cube
  • attach the camera to the cube
  • add this script in the post to the cube

Walk and ‘jump’…
Is this a bug?

Just give rigidity to gameobject if not given.
Instead of moveDirection.y*upspeed.

Do rigidbody.addforce(Vector3.up*upspeed)

Let object fall with gravity