Fuel Pump: Description

Two types of fuel pumps are currently used. Most gasoline vehicles use an engine-mounted mechanical pump. General Motors diesel models also use a mechanical pump to supply fuel to the injector pump. Vehicles with fuel injection use an electric pump. General Motors models use a low pressure (8-14 psi) pump.

Vehicle manufacturers recommend that the pump be replaced as an assembly if found defective. Check pumps for fuel pressure, volume, and vacuum (suction). DO NOT  attempt to overhaul or repair pump assembly. Some pumps will have an extra connection for fuel and vapor return to aid in hot starting and prevention of vapor lock.