Procedures

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

Although the fuel pump can be controlled with the ignition, this is fairly awkward since:
^ 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).
^ Some tests are run with vehicle on hoist with control of pump under car required.
^ The pressure at flow tests require pump to run for 10-20 seconds.

The Scan tool provides control of the fuel pump at the technician's finger-tips. The tool will run the pump for 30 seconds 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 30 seconds 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
Control of the fuel pump is under the SPECIAL TESTS menu.
^ Once in SPECIAL FUNCTIONS, select POWERTRAIN
^ Select FUEL SYSTEM

IMPORTANT: The one minute timer for fuel pump operation is in the "Fuel Tank Drain" function.

^ Then select desired function (fuel tank drain, injector balance, etc.)