iOS Tilt input and constant force

I'm working on an iOS game similar to Temple Run. I'm working on the player controls and come across a problem. I had added a constant force to move the player forward, and this had worked, until I added the tiltInput script for iOS. The constant force then works when testing the game on my desktop, but when I connect my iPhone, and test the game on there, there is no constant force but the tilt input works.

Here is the code for the runner:

 using UnityEngine;
 
 public class Runner : MonoBehaviour {
 
     void Update () {
         transform.Translate(5f * Time.deltaTime, 0f, 0f);
     }
 }

and here is the tilt input script, that Unity gives us:

 using UnityEngine;
 using System.Collections;
 
 
 
 public class tiltInput : MonoBehaviour {
     
     public Vector3 tiltVector = Vector3.zero;
     
     public Transform cube;
     public int speed = 1;
 
 
     void Update () {
         tiltVector = Input.acceleration;
         
         cube.Translate(-Vector3.back * speed * tiltVector.y);
         
         
         if(tiltVector.y > 0){
             Debug.Log ("Cube is traveling left! X Vector is: " + tiltVector);
         }
         
         if (tiltVector.y < 0){
             Debug.Log ("Cube is traveling right! X Vector is: " +tiltVector);
         }
     
     }
 }

Can anybody help at all?