Alero L4-144 2.4L DOHC VIN T SFI (2000)
diaphragm. The low pressure (high vacuum) will offset the pressure being applied to the fuel pressure regulator diaphragm by the spring inside of
the fuel pressure regulator. This will cause lower fuel pressure. The fuel pressure at idle will vary slightly as the barometric pressure changes, but
the fuel pressure at idle should always be less than the fuel pressure noted in Step 2 with the engine turned off
12. A rich condition may result from the fuel pressure being above 405 kPa (58 psi). A rich condition can cause a DTC P0132 or a DTC P0172 to set.
Driveability conditions associated with rich conditions can include hard starting followed by black smoke, and a strong sulfur smell in the exhaust.
13. This test determines if the high fuel pressure is due to a restricted fuel return pipe or if the high fuel pressure is due to a malfunctioning fuel
pressure regulator.
15. A fuel pressure of less than 358 kPa (52 psi) can cause a lean condition. A lean condition may cause a DTC P0131 or a DTC P0171 to set.
Driveability conditions associated with lean conditions can include hard starting when the engine is cold, a hesitation, reduced driveability, a lack
of power, surging, and misfiring.
16. Restricting the fuel flow causes the fuel pressure to rise above the regulated fuel pressure. Using a scan tool in order to pressurize the system, the
fuel pressure should rise to more than 405 kPa (58 psi) as the gauge outlet hose is pinched.
22. Inspect the spark plug that is associated with a particular fuel injector for fouling or saturation in order to determine if that fuel injector is leaking.
