To pressurize the system and check for fuel leaks… do not start engine, but let the ECM power the fuel pump for 5 seconds when energized. Have a Fire extinguisher available for use at all times.
The Fuel Injector is installed and torqued during the manufacturing process and should not be replaced/tightened under normal circumstances , but if replacement is directed a strict replacement torquing is required. If the injector is over-torqued, it will cause the injector to malfunction.
If the injector is leaking from the injector top seal, lightly tighten each side until the leak has stopped or until a slight resistance is felt then STOP. The injector may also leak a small amount of fuel initially, but then the o-ring will seal the leak shortly after use. A small amount is a drop or 2, not a spray or an amount that would cause a fire risk. If the injector seal continues to leak fuel, then a replacement seal must be installed and injector housing checked before re-installation.