Nope, that just means the part is badly damaged. Don’t go running over any zeds before repairing it or you might be in trouble.
As for the pump, each pump has a random amount of fuel left in it, don’t know the min/max numbers myself but it’s not unusual that you can’t top off entire tank from a small pump like that. There are larger pumps out there with two rows of pumps that will usually have enough to fill larger vehicles.
Also, does that vehicle have more than one tank?