Energizing the Fuel Pump

Energizing the Fuel Pump

All of the fuel system tests will require operation of the fuel pump to measure pressure, evaluate pressure decay, or perform the pressure at calibrated flow tests.

Although the fuel pump can be controlled with the ignition, this is fairly awkward since 1) the pump is only energized for 2-3 seconds at Key On. (and then a wait of 10 seconds is required after Key Off before the pump can be powered again), 2) some of the tests are run with the vehicle on the hoist with control of the pump under the car required, and 3) the pressure at flow tests require the pump to run for 10-20 seconds.

The Scan tool provides control of the fuel pump at the technicians finger-tips. The tool will run the pump for one minute after the On command. This timer will then shut the pump Off.

NOTE: Once the fuel pump is commanded On with the Scan tool, it will be energized for one minute before it times out and returns to the Off status. Do not leave the vehicle unattended while running any of the system tests with the pump On.

Operating the Fuel Pump/Injector Balance Test
Control of the fuel pump and injector is under the SPECIAL FUNCTION menu.
^ Once in SPECIAL FUNCTION, select Powertrain
^ Select FUEL DELIVERY
^ Then select desired function (fuel pump, injector balance, etc.)