Fuel gauge limiter

You're trying to get power from a ground wire??? Remember that the wire to the sender is a ground. Do you have the ground jumper strap installed between the sender and the steel fuel line?

Yes, it is possible for the fuel gauge to not have power while the temperature gauge does, depending on what model car you have. Some models have the voltage limiter installed right in the fuel gauge while others do not.

You'll have to pull the cluster to check out what's really happening.