Sprinkle gelatin over water and let stand 1 minute.
Combine sugar, cocoa, evaporated milk, egg substitute, and vegetable oil in a heavy saucepan.
Cook over medium heat, stirring constantly, until smooth and thickened.
Remove from heat.
Stir in vanilla extract and chocolate syrup.
Add gelatin mixture. Stir until gelatin dissolves.
Chill until the consistency of unbeaten egg white.
Beat egg whites with cream of tartar at room temperature until stiff peaks form.
Fold into chocolate mixture.
Spoon filling into graham cracker crust.
Cover and chill until pie is firm.