So what is an IPR valve, and what is it’s purpose? Well, IPR stands for Injection Pressure Regulator, and to give the logical answer to it’s function, it regulates the injection pressure. Although that is a technically accurate answer (such as you might get from a certain software supplier), it does not really answer the question. So what is an IPR valve really for?
Function of the IPR valve
Controlled by the PCM (Powertrain Control Module), the IPR regulates the oil bypass circuit of the high pressure pump. Located on the back of the high pressure oil pump, this electromagnetic valve opens and closes to allow high pressure oil into the injectors. The PCM controls fuel delivery to the injectors by altering the IPR duty cycle, which adjusts fuel pressure through the injector nozzles.
The IPR has only two settings:
- Open – full return to sump
- Closed – full flow to injectors