It is simple to unhook the power to the injector. On top of each injector there is a wire connected to it. push the red tab up on the connection, and it will allow you to unhook the connector. Start with piston #1 and work your way back. Listen for a change in the noise after you unplug the injector. Plug it back in and move to pistion #2, keep doing this until you reach the last pistion. In my case, once I reached pistion #6, the sound was dramtically quiter.