How can I troubleshoot the fuel system of an Audi 80?

I've noticed some issues with my Audi 80's fuel system, but I'm not sure where to begin troubleshooting. The car's fuel pump seems to be constantly running, and there's a strange smell coming from the fuel tank. What could be causing these problems and how can I fix them?

First of all, check the fuel filter and fuel pressure regulator for any clogs or malfunctions. This is often the culprit for fuel system issues. If those are functioning properly, it could be a faulty fuel pump relay. Try replacing that and see if the symptoms improve.

If the fuel system seems to be causing a strange smell, it could be a sign of a fuel leak. Check all fuel lines and connections for any cracks or leaks. Also, make sure the fuel cap is tight and not allowing any fumes to escape. It's important to address any leaks promptly for safety reasons.