I'm working on getting my S5 engine into S4 finally finished. I'm using the S4 injectors with the S5 fuel rail. However, I'm finding the injectors fit very loose when the rail is bolted down. It is very easy to turn the injectors and there is very little resistance. I'm just wondering if the injectors are supposed to fit tighter so I'm not spraying fuel everywhere the first time I pressurize the system. Has anyone else enountered anything like this?

 

Are you using newer grommets and O-rings? It is okay if the injectors turn one way or the other... But you want to be VERY sure that they are sealing properly.

 

it is normal for the injectors to fit rather loosely.

it is when you start modifying the car and turning up the boost is when it becomes more important to shim the injectors to keep them seated better and prevent boost leaks.

 

How do I ensure the injectors are properly sealed before pressurizing with fuel? Or do I just pressurize the lines and be ready to switch the car off quickly?

 

fuel pump test connector is at the RF strut tower on the engine harness, yellow connector 2 pin plug open and dangling on the harness. key on with the connector jumpered the fuel pump will run, the rest i will leave up to common sense.