What does the fuel pressure regulator do?
The fuel pressure regulator controls the amount and pressure of the fuel that enters into each of the engine’s fuel injectors. Most engines use one of two distinct types of regulators. The first - and older - of the two works on engine vacuum. A rubber hose attaches to the intake manifold to one half of the regulator. As engine RPM rises, the suction from the manifold as air is drawn into the cylinders pulls on a diaphragm inside the regulator which opens the fuel line for more volume and pressure. The second more modern regulator is computer controlled. The computer uses input from a fuel pressure sensor, throttle position sensor and other load measuring sensors to send commands to open or close the regulator.
What are the symptoms of a faulty fuel pressure regulator?
An engine that runs poorly, and eventually may not run at all. Usually when a fuel pressure regulator fails, the pressure usually spikes. This is designed to keep the car driveable in the short term. High pressure will put extra fuel into the cylinders even when not called for, so the engine will run rich. You may notice a sputtering or misfiring particularly when the car idles. The exhaust will become darker, almost black in color and smell like rotten eggs as the converters become overwhelmed.
How severe is a faulty fuel pressure regulator?
Significant. A failing fuel pressure regulator may not leave you stranded on the side of the road; at least not right away. However, if neglected, you will be calling the tow truck and you may be paying for additional repairs. Remember an engine does not like to run rich; carbon will build up quickly, and the catalytic converter life will be shortened. It's best to find a good mechanic and set an appointment before the car ends up on the hook. Most repairs may be performed same day unless the part needs to order from the dealer.
What is the typical cost to replace the fuel pressure regulator?
- Estimated part(s) cost = $50-$300
- Estimated labor cost = $50-$300
- Estimated total cost = $100-$600
The price of the part is completely dependent on the type of regulator the engine uses. It will also depend if the part is sold with the fuel rail, which will add to the price. For a vacuum driven regulator look for a price in the range of $50 to $200 dollars. The computer operated regulator will be more expensive, usually in the range of $150 to $300. Most fuel pressure regulators are easily accessible, although some will require more breakdown to reach the regulator or if the whole fuel rail must be removed. Look for installation costs in the range of $50 to $300.
Not only will pricing vary by engine type, but by location as well. If you're not already, save time and money by using Openbay to compare pricing and book an appointment with a service center in your area.
Service article written by an ASE Master Technician