Part 2 of 2
Chart A-7B (Part 2 Of 2):
Fuel System Circuit:
CIRCUIT DESCRIPTION:
When the ignition switch is turned to the "ON," position the Electronic Control Module (ECM) will energize the fuel pump relay for 3 seconds, allowing for fuel pump operation. If the engine is being cranked, or is running, the fuel pump will continue to operate, as long as the ECM is receiving ignition reference pulses. If the ignition reference pulses are not detected, the fuel pump will stop after 3 seconds. The fuel pump will deliver fuel through the fuel filter to the fuel injector and fuel pressure regulator, where the system pressure is controlled at 240-280 kPa (34-41 psi). Excess fuel is returned to the fuel tank by means of a fuel return pipe.
TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.
5. Checks for leaks at the fuel pump hose connections, for a faulty fuel pump or a faulty fuel pressure regulator.
6. Checks for restricted fuel feed pipe, faulty fuel filter or restricted return fuel pipe.