Q: Ran out of gas ('92 Mercedes 500SL) now the car will not start after adding gas

If the car is on level ground, the 2.5 gallons should be enough to cover the fuel pickup. If the car is on a hill, or leaning to one side or the other, it might help to add more gas. However, it may be that the fuel pump is toast. On Bosch fuel systems like the one on your Mercedes, the fuel passes through the fuel pump motor to cool and lubricate it. When the cars get old, the pump is tired and running the fuel pump dry is often enough to finish it off. You will need to have a fuel pressure test to be sure, but it’s not unusual to have to replace the pump on an older Benz that has been run out of gas. If you contact Your Mechanic, you can have a technician come out to your home or office to check out your Mercedes and let you know why it won’t start up.