Fuel Pressure Regulators
The fuel pressure regulator (FPR) is a device mounted on the fuel rail and is usually connected to intake vacuum. The internal diaphragm inside the regulator dictates the amount of pressure in the system.
Remember, pumps don’t create pressure; they create volume. The resistance put on the output volume of the pump creates the actual pressure. In the case of automotive fuel systems, this is often the job of the fuel pressure regulator. Some fuel pressure regulators are adjustable and you can dial in the proper pressure. If this is the case, try to dial in your FPR and see if your performance issue goes away. If it does, great; you can move on with your life. If not, we need to keep working.
As I said, many FPRs are hooked up to intake vacuum. If there is a leak in this vacuum line or it’s not getting vacuum to the FPR, then what you would normally see is high fuel pressure all the time. In fact, when you pinched off the fuel return line, you would likely see little to no change. High fuel pressure can cause issues just like low fuel pressure. So if you find a vacuum feed problem, address it and recheck for your performance issue.
While we’re in the topic of the FPR a good visual inspection is also in order. Remove the vacuum line and check for fuel. If you see fuel here, your FPR is bad. There should be no fuel leaking out into the vacuum line. Also, when doing your fuel pressure test, remove the vacuum line going to the FPR. When you do, there should be a rise in fuel pressure. If not, this would indicate a problem with the FPR and it should be replaced. FPRs are not usually expensive, so if you suspect a problem with one, it’s usually not much of an expense to replace it.
Video Title: Fuel Pressure Regulators – Solving Automotive Performance Issues – EricTheCarGuy Video Description: In this Article, Fuel Pressure Regulators, we look at how Fuel Pressure Regulators can impact Engine Performance. Thumbnail: http://www.ericthecarguy.com/images/faq_buttons/Large_FAQ_Images/Performance-and-Driveability-icon-1200.jpg