http://cgi.ebay.com/RF-Wireless-Electric-G...#ht_3120wt_1139

Dry relay contacts, so could switch on or off anything, including the fuel pump. 10 amp on 12V relays, plenty for a pump.

I have a similar relay for my car. Mine looks like a standard Bosch relay. I use it to cut off the fuel pump. Mine works by turning on the key, this provides power to the relay common and the internal electronics. I then have to push the remote button. I have 20 seconds to start the car and receive the fuel pump on signal from my EFI. If the relay does not see the fuel pump signal in 20 seconds, it turns off. I have to push the button again. When I turn off the car and the fuel pump signal is off, 20 seconds later the relay disables. I have to push the button again to start.

I got mine on ebay too but I haven't seen them in a while. I bought two, just in case...