Cavalier/Z24 L4-144 2.4L DOHC VIN T SFI (1996)
Diagnostic Chart
Gauge Hookups
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, the Powertrain Control Module (PCM) will turn ON the in-tank fuel pump. The in-tank fuel pump will remain
ON as long as the engine is cranking or running and the PCM is receiving reference pulses. If there are no reference pulses, the PCM will turn the in-tank
fuel pump OFF 2 seconds after the ignition switch is turned ON or 2 seconds after the engine stops running. The in-tank fuel pump is an electric pump
within an integral reservoir. The in-tank fuel pump supplies fuel through an in-line fuel filter to the fuel rail assembly. The fuel pump is designed to
provide fuel at a pressure above the pressure needed by the fuel injectors. A fuel pressure regulator, attached to the fuel rail assembly, keeps the fuel
available to the fuel injectors at a regulated pressure. Unused fuel is returned to the fuel tank by a separate fuel return pipe.
TEST DESCRIPTION
Number(s) below refer to the step number(s) on the Diagnostic Table.
2. To relieve the fuel pressure, go to Fuel Pressure Relief Procedure When the ignition switch is ON and the fuel pump is running, the fuel pressure
indicated by the fuel pressure gage should be 284-325 kPa (41-47 psi). This pressure is controlled by the amount of pressure the spring inside the
fuel pressure regulator can provide.
3. A fuel system that can not maintain a constant fuel pressure has a leak in one or more of the following areas:
