Fuel Pressure Regulators

Fuel pressure regulators have long been used on electronic fuel injection systems. They maintain fuel pressure within the specified range. A fuel pressure regulator is mounted to the fuel rail and contains a spring and a diaphragm. A port connects the regulator to engine vacuum and it is also connected to the fuel return line, which allows fuel to flow back to the tank. At idle, when less fuel is required, engine vacuum acts against the spring and diaphragm to allow excess fuel to flow back to the tank. When the throttle is opened and more fuel is needed, the reduced vacuum under such conditions allows the spring and diaphragm to restrict return flow, ensuring there is enough pressure for the increased pulse width.

A fuel pressure regulator will typically fail closed, resulting in too much fuel pressure, a rich mixture, poor fuel economy and excessive emissions. If you disconnect the vacuum hose from the regulator and the fuel pressure doesn’t rise, the regulator is most likely faulty. However, there could be a problem with the vacuum signal, caused by a cut or broken vacuum line, so to be sure, apply vacuum with a hand-held vacuum pump. Fuel pressure should drop as vacuum is increased. If it doesn’t, verify that the return line isn’t blocked, and if not, replace the regulator.

However, if the spring in the regulator breaks or the regulator leaks, this will result in fuel pressure that is too low and a lean condition. If fuel pressure is low and doesn’t rise when the fuel return line is pinched shut, the fuel pump is most likely at fault. However, if the pressure does rise, the regulator should be replaced. Regardless of the failure mode, we have the replacement fuel pressure regulator to restore proper engine operation. All of the regulators we offer are manufactured to OE specs to meet the specific fuel pressure requirements of each vehicle, and ensure ease of fitment and perfect engine performance.

Fuel pressure regulators deliver satisfactory performance – as long as the rest of the fuel system remains in factory stock configuration. But install larger injectors, forced induction, a high volume fuel pump or other mods, and the OE regulator becomes inadequate. We have pressure regulators to suit every type of fuel system and level of modifications, from direct fit upgrades to units designed for full custom high flow fuel systems. The main problem with OEM regulators is that they can’t be adjusted, and being able to increase fuel pressure may be all you need to do with moderately larger injectors to achieve the optimal air/fuel ratio. We offer adjustable regulators that are direct bolt-on replacements for the factory component on select applications, so you can tune your EFI car for peak performance. Many of these are manufactured from billet aluminum and come with attractive finishes to complement your engine.

If you’re building a full custom designed electronic fuel injection system, we offer pressure regulators for everything from street/strip applications right up to 3000 horsepower drag racing engines. These regulators are adjustable, compatible with gasoline and alcohol, and available to complement a wide range of fuel pump flow rates and fuel system configurations. We have static regulators for returnless systems and for use with external fuel pumps connected to return lines, as well as bypass regulators with a port to return excess fuel to the tank. Many have vacuum/boost reference ports. These pumps are CNC machined from billet aluminum, with an attractive finish and feature as many as 4 inlet ports. We also offer pressure regulators specially designed for carbureted applications.