Chart A2-7B Fuel System Pressure Check

Chart A2-7B Part 1 Of 2:

Chart A2-7B Part 2 Of 2:

Fuel Delivery System Schematic:

CIRCUIT DESCRIPTION
When the ignition switch is turned to the "ON" position, the Engine Control Module (ECM) will turn "ON" the in-tank fuel pump. It will remain "ON" as long as the engine is cranking or running and the ECM is receiving reference pulses. If there are no reference pulses, the ECM will shut "OFF" the fuel pump in about 2 seconds after ignition "ON" or engine stops.

The fuel pump will deliver fuel to the throttle body fuel injector, then to the fuel pressure regulator, where the system pressure is controlled to about 160-210 kPa (23-31 psi) depending on engine operating conditions. Excess fuel is then returned to the fuel tank.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.
(Part 1 of 2)
1. Checks to see if fuel system pressure is within specifications.
2. Checks fuel feed pipe and hose for leaks.
3. Checks for faulty fuel pump or a leaky fuel filter.
4. Checks for a leaky fuel injector, throttle body or for a faulty fuel pressure regulator.
(Part 2 of 2)
5. Checks for restricted fuel feed pipe, or fuel filter or for a faulty fuel pressure regulator.
6. This determines if there is a restricted fuel return pipe or fuel pressure regulator.

DIAGNOSTIC AIDS
Improper fuel system pressure can result from one of the following conditions:

^ Cranks, but won't run.
^ Cuts out, may feel like ignition problem.
^ Poor fuel economy, loss of power.
^ Hard starts.