I would agree. The olive oil and lemon/grapefruit juice works in about 20 minutes on an empty stomach, in a lot of people anyway. There may not be a problem with your liver or gb but there again it may not have a fully establish reflex action and it may a few flushes to start the process going. Every one appears to have a different reaction.
If you feel nauseas after the oo and lj potion then try some liver salts such as Andrew or alka seltzer.