Mobile Repair Fleet Services

Signs of a Failing Fuel Pressure Relief Valve

The new and advanced diesel engines are made up of intricate parts that are in place to protect the engine from faulty codes and possible breakdowns. This part, the fuel pressure relief valve or (FPRV), is one of many important parts in place to supply the engine with the protection it needs from unwanted things reaching the chamber. The FPRV is an 18mm plug with the characteristics of a large screw that plugs into a diesel engine's pump on the fuel rail's driver side. It operates similarly to a sealant and shields the engine during operation with the technology to turn its systems off when the vehicle is not running.

What is a fuel pressure relief valve?

A fuel pressure relief valve is in place to help eliminate unwanted, cruel emissions from fuel leaking through the fuel injectors. The FPRV operates as a seal to prohibit flow through the valve. When a vehicle is being driven and the temperatures have decreased, the valve then unseals. This system is in place to prevent pressure build-up from high or rising temperatures. In more defined terms, the FPRV permits high-pressure fuel from entering the leak system to eliminate either an increase or decrease in fuel pressure. Any excess fuel pressure that is identified is returned to the fuel tank and controlled by the engine control module. 

What are the signs of a failing fuel pressure relief valve? 

A failing fuel pressure relief system and valve may show in different ways that it is performing poorly and, on its way, to complete failure. The fuel pressure system is made of several different components in support of the engine, and the engine's purpose is to provide power to the vehicle for ignition and running. Here are some of the many signs of a failing fuel pressure system and valve. 

  • Engine misfires
  • Decreased power
  • Decreased fuel efficiency
  • Fuel leakage
  • Black smoke from the exhaust system 
  • Smell of fuel 
  • Engine malfunction
  • Noisy fuel pump
  • Hard Start or no start at all 
  • Fault codes 
  • The system can't reach the designed pressure
  • Valve is leaking or has no pressure

Maintenance tips to protect the fuel pressure valve

A failing fuel pressure relief system and the valve are preventable through the acts of proper, routine maintenance. Maintenance in a diesel-powered vehicle of any kind goes a long way in protecting the engine and its parts from breaking down which can result in costly repairs for the owner. Diesel engine experts highly recommend regularly replacing the fuel filter and ensuring the water separator is properly drained. These two procedures, along with some other required maintenance processes such as tune-ups, oil changes, and fluid checks can make known any issues going on underneath the hood of a diesel-powered vehicle. Maintenance allows proactive auto solutions for all vehicles by making known small problems before they become major or more complex issues like complete engine replacement or repair. Visit a qualified diesel-engine professional if any or all the listed symptoms have arrived within your diesel vehicle.