2014 C7 base
Manual transmission
10K miles
Edelbrock Supercharger

Customer brought this vehicle to me for a rattle noise heard inside. It is heard mainly from the dash and shift console area. Not speed or gear related. Consistent with injection pulse. I have narrowed it down to the fuel line. I can take a stethoscope and put it on the fuel line coming off the firewall in the engine compartment. I removed the center console and shifter and can hear and feel the same noise on the fuel line right next to the torque tube. This vehicle is equipped with the Edelbrock supercharger installed by another shop several years ago. I noticed the fuel line that was installed with the Edelbrock kit in place of the factory one was just a straight pipe with No check valve. The factory fuel line has a check valve. I also know of the GM bulletin for this issue on a stock engine is to replace the fuel line with a new check valve. I contacted Edelbrock and they have since updated their kit to include a pipe with a check valve. I installed this new pipe and the noise is just a little quieter but still can be heard.

I see that Lingenfelter has a inline check valve that they make that offers higher flow and specifically calls out to prevent noise inside the car but looks to be designed for AN fittings.

I've installed dozens of C7 superchargers and have not had any issues like this. I'm leaning toward the injection pump and lifter. Looking to see if anyone has had this issue.

Here is a pic for comparison of the factory pipe with check valve vs the Edelbrock straight pipe. And yes inside that little black hose with the clamp is the check valve.