Are the fuel pumps on the cars mechanical or electrical?

May be...

mechanical

electrical.

They are mechanical for safety reasons.

The fuel pumps on NASCAR cars are mechanically driven for safety reasons. You don’t want the fuel pump on a crashed car to continue to pump fuel. The Waterman fuel pump, is a cable-driven pump that is mounted on the fuel cell (as opposed to on the engine). This type of fuel pump is run on the Chevy R07 engines, but I understand that the 2008 Toyota engines (which I assume Hamlin would have been running) also use this type of pump. (interesting explanation...this answer is half way down the page).

*MOJO*

Mechanical

They are a mechanical pump. Within the last couple years, they switched to the Waterman pump. It driven by a cable, and mounts in the rear of the car. If you'll remember, the Gibbs teams had some problems with it last year. Tony was dominating at Bristol, and the cable broke.
They switched to this system because it was safer than having the pump mounted on the motor. Remember how the Chevys used to be very susceptible to fire when they hit the wall hard with the right side of the car? It was because the pump was mounted right inside the frame rail, on the side of the motor. And when the car hit hard enough, it would shear the pump right off. They even had one of those computer simulation graphics that they would show , after it would happen during a race.

They are mechanical.danelli venice