Bad Fuel Pressure Regulator: Is Your Fuel Mileage Worse?

April 16th, 2015 by

Bad Fuel Pressure Regulator
According to eHow, the fuel system in a car is made up of several components and if any part of that system is flawed your car can run erratically, or it might not be able to run at all. The job of one of those components—the fuel pressure regulator—is to make sure the correct amount of fuel is received by the engine. If too much fuel flows to the engine, it is the job of the regulator to return excess fuel to the fuel tank, according to If the regulator is malfunctioning, your engine may flood with fuel or cause decreased gas mileage. Here are symptoms of a bad fuel pressure regulator and how to test to make sure the fuel pressure regulator is the root of the problem.

Bad Fuel Pressure Regulator Symptoms

  • The engine is running rough
  • The engine sputters or stalls when you are driving
  • Fuel mileage suddenly worsens
  • You notice black smoke coming out of the exhaust
  • Your car won’t start

Testing to Detect a Bad Fuel Pressure Regulator

Just like when testing the fuel pump for issues, you’ll need a fuel pressure gauge to rule out the fuel pump and fuel line. View our previous blog to learn how to use a fuel pressure gauge. If the pressure reading shows a number other than what it should be, then the issue may lie with the pump itself or the fuel line. If the gauge reads the correct number, then the issue may still be a bad fuel pressure regulator.
Bad Fuel Pressure Regulator
To test the fuel pressure regulator itself you’ll need to locate the regulator on the fuel line. Once you have found the regulator you’ll then need to remove the vacuum hose. The vacuum hose is the part of the fuel system that connects the fuel pressure regulator to the many pipes that bring fuel to the engine, according to eHow. If fuel drips from the hose as you remove it from the regulator, then a bad fuel pressure regulator may be the culprit.
Another way to tell if you have a bad fuel pressure regulator is by starting the engine with the fuel pressure gauge, according to eHow. Attach the gauge back to the fuel pressure valve. When you remove the vacuum hose the reading on the gauge should jump by 5 to 10 psi. If the reading on the gauge stays the same then it’s probably time for a new fuel pressure regulator.
Call Fisher Auto in Boulder, Colo., at 303-245-6414 to have your fuel pressure regulator checked if you are experiencing any of the symptoms of a bad fuel pressure regulator.