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
Replacing an IPR valve on a Powerstroke engine takes a little time and effort. If you know what you’re doing, a few little tricks can save you time and alot of clean up.
1. Remove the oil plug from the high pressure reservoir and remove as much of the oil as possible. A turkey baster with a small hose attached to it works well.
2. The next step is to drain the fuel filter bowl.
3. Remove the intake “Y” and block open ports to prevent debris from falling into them. All wires and hoses must be loosened or removed that connect to the fuel filter housing and the IPR valve.
4. Take out the two bolts and lift the fuel filter housing away from the engine and up out of the valley.
5. Remove the nut holding the IPR solenoid in place. Take of the solenoid. Use a socket to remove the IPR valve. Go slow and take care not to knock debris back into the opening.
6. Coat the IPR o-rings with engine oil and replace them. Replace the solenoid and reattach any wiring.
7. Clean the valley with carburator cleaner, clearing away debris and used oil.
8. Replace all wires and hoses and reassemble the motor.
9. Using a small funnel, add approximately one quart of oil to the reservoir and reattach the plug.
10. Start the engine and allow it to run for awhile.
It will take a few minutes for the idle to stabilize. It should begin to run smoothly after about 5 minutes.