Fuel Pressure Regulator: Description and Operation
OVERVIEWFuel pressure in the cylinder head fuel galleries is maintained at 310-448 kPa (45-65 psi) by a fuel pressure regulator. The fuel pressure regulator consist of a spring-loaded poppet valve, which opens to allow excess fuel to exit fuel filter/water separator prior to being cycled through the fuel filter. Fuel exiting the fuel filter/water separator is returned to the fuel tank.
INJECTION PRESSURE REGULATOR
Fuel injection pressure is controlled by the Injection Control Pressure (ICP) system. The ICP system consists of:
^ injection control pressure (ICP) sensor (located in the cylinder head oil gallery)
^ Injection Pressure Regulator (IPR) located in the high-pressure oil pump
^ powertrain control module
The Injection Pressure Regulator controls injection oil pressure. An electrical signal to a solenoid creates a magnetic field which applies a variable force on a valve servo to control pressure. The quantity of fuel delivered to the combustion chamber is proportional to injection control pressure.
An open circuit will result in minimum oil pressure and a no-start situation. A short circuit results in maximum oil pressure, and is limited by a mechanical pop-off valve to 27,580 kPa (4000 psi).
INJECTION CONTROL PRESSURE SENSOR
The Injection Control Pressure sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a linear analog voltage signal that indicates pressure. The sensor measures the oil pressure in the LH injection rail. PCM uses this information to determine injection control pressure. The Injection Control Pressure sensor along with the Injection Control Pressure Regulator form a closed loop fuel pressure control system.
If the PCM detects an inoperative Injection Control Pressure sensor, the PCM will control injection control pressure from a PCM-estimated injection control pressure.