Basement sink has a sewer injector that is vented bank into the sink and I get a sewer smell should it be vented outside to get rid of the smell.
Thanks,
Chip

Please explain "vented back to the sink". Is this a common vent? Ejector pumps are code required to have a dedicated vent to the outside.

I understand that you have vented back to the sink vent. That is incorrect. But the pit vent should be dedicated and ran outside. The reason for this is that when you drain your sink into the holding tank it expels and when the tank drains it told air back in. Run the holding tank then outside and the smell goes away. Good luck, Tom