Injection Pressure Regulator (IPR)
The IPR controls the injection oil pressure. An electrical signal to a solenoid creates a magnetic field which applies a variable force on a valve servo to the control the pressure. The quantity of fuel delivered to the combustion chamber is proportional to the injection control pressure.
An open circuit results in minimal oil pressure and a no-start situation. A short to ground in a circuit results in maximum oil pressure, limited by a mechanical pop-off valve to 27,580 kPa (4,000 psi).