In-Tank Pump

The tank pump, containing a winged impeller, is electrically operated and is used to maintain pressure in the line from the fuel tank to the main pump, preventing vapor lock from forming in the line.
The pump operates whenever the ignition switch is in the ``On'' or ``Start'' position. Fuel is drawn into the chambers between the impeller wings that rotate within a stepped chamber, then is forced into the line to the main pump.
A check valve at the pump outlet prevents fuel from returning to the tank when the pump is not operating.