Angular 2 View will not update after variable change in subscribe

are you seeing any error on console?
This could be due to fact that angular is not running change detection after you have made updates to value.
I think you don’t need ngZone.run as it will run code outside the angular zone.

this.questionService.onSubmit(form, this.questions).subscribe( (value) => {
            this.fileLocation = JSON.stringify(value);
            console.log(this.fileLocation);
            this.isRequesting = "false";
            console.log(this.isRequesting);
    });

If due to some reason you need to run this outside Angular zone, then you should inform angular to run a change detection cycle by either of this method.

• just wrap update of isRequesting in set timeout

  setTimeout( () => this.isRequesting = "false", 0);
  

• invoking change detection manually

  import {ChangeDetectorRef} from '@angular/core'
  constructor(private ref: ChangeDetectorRef){}
  
  this.questionService.onSubmit(form, this.questions).subscribe( (value)=> {
      //existing code
      console.log(this.isRequesting);
      this.ref.detectChanges();
  });