NISSAN 22670-5L31A Fuel Pressure Regulator Assembly

The genuine OEM Nissan (SKU: 22670-5L31A) fuel pressure regulator assembly is a critical component in the vehicle's fuel supply system. Its primary function is to continuously maintain the specified, stable fuel pressure in the fuel rail relative to the intake manifold pressure, ensuring accurate and efficient operation of the fuel injectors.

Technical Features and Construction

• Type: Vacuum-operated, diaphragm-type fuel pressure regulator valve.
• Material Quality: Premium, corrosion-resistant metal alloy housing designed to withstand the chemical properties of fuel and high engine temperatures.
• Sealing: Connection surfaces equipped with dedicated fuel-resistant O-rings to ensure leak-free mounting.
• OEM Quality: Genuine Nissan OEM part, guaranteeing factory-specified flow rates and pressure regulation range.

Operating Principle and Importance

The fuel pressure regulator directly affects engine performance and emissions. As engine load varies, manifold vacuum changes accordingly. Utilizing this vacuum signal, the regulator modulates the amount of fuel returned via the return line, keeping the pressure differential across the injectors constant relative to manifold pressure. This is essential for optimal atomization and an efficient combustion process.

Typical Symptoms of Failure

Wear or a ruptured internal diaphragm in the fuel pressure regulator can lead to the following symptoms:

• Hard starting: Rapid loss of rail pressure requires extended cranking for the system to rebuild proper starting pressure.
• Rough idle and engine hesitation: Fluctuating fuel pressure causes an unstable air-fuel mixture.
• Increased fuel consumption and black smoke: If the regulator sticks closed and allows excessive pressure, the engine runs overly rich.
• Fuel leak into the vacuum line: A damaged diaphragm can allow fuel to enter the intake system through the vacuum hose, leading to severe running issues.