My bone stock 1977 Corvette (350 ci with automatic transmission) with about 90K original miles on it passed the tailpipe emissions test part of the California smog test, but failed the "evaporative emissions" part of the test.

From what I understand, to do the evaporative emissions test, they pressurize the fuel system (by taking off the gas cap and attaching their device to the fuel fill pipe?) and check for a leak down of pressure. If there is a loss of pressure, then there must be gasoline vapor escaping into the atmosphere.

So my question is, what is the likely place for this leak and how can I fix it?

 

Welcome to the forum.

I'd checked the charcoal canister and the vacuum operated valve on it along with all hoses connected to the system.