Mechanics

FUEL PRESSURE REGULATOR

2005 Ford Expedition

Smells problem
2005 Ford Expedition V8 Four Wheel Drive Automatic 990000 miles

I OWN A 05 EXPEDITION EDDIE BAUER COMING HOME FROM A SOMEWHAT LONG TRIP THE SUV STARTED RUNNING ROUGH SMOKE CAME OUT OF THE EXHAUST AND IT HAD A STRONG SMELL OF FUELCOMING FROM THE EXHAUST ALSO THE CHECK ENGINE LIGHT CAME ON TOOK IT TO READ THE CODES AND IT CAME BACK THAT IT HAD TWO MISFIRES ON CYLINDER 3 AND 4 WENT AHEAD AND REPLACED SPARK PLUGS BUT COULDNT REPLACE THE COILS I TEST DROVE IT NOW THERES SEEMS TO BE FUEL COMING OUT OF THE EXHAUST I HAVE READ THAT IT COULD BE A FUEL PRESSURE REGULATOR OR A BAD INJECTOR CANT FIND THE REGULATOR ON THE EXPEDITION COULD YOU TELL ME WHERE IT IS OR IF THIS IS REALLY BAD NEWS FOR MY TRUCK
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Juan73
February 22, 2009.



Fuel Injector
The fuel injector is a solenoid-operated valve that meters fuel flow to the engine. The fuel injector is opened and closed a constant number of times per crankshaft revolution. The amount of fuel is controlled by the length of time the fuel injector is held open.
CAUTION:Do not apply battery positive voltage (B+) directly to the fuel injector electrical connector terminals. The solenoids may be damaged internally in a matter of seconds.

The fuel injector is normally closed, and is operated by 12-volt VPWR from the electronic engine control power relay. The ground signal is controlled by the PCM.
The injector is the deposit resistant injection (DRI) type and does not have to be cleaned. However, it can be flow checked and, if found outside of specification, the fuel injector should be replaced.

Fuel Pressure Regulator
The fuel pressure regulator is attached to the fuel rail downstream of the fuel injectors. It regulates the fuel pressure supplied to the fuel injectors. The regulator is a diaphragm-operated relief valve. One side of the diaphragm senses the fuel pressure and the other side is connected to the intake manifold vacuum. Fuel pressure is established by a spring preload applied to the diaphragm. Balancing one side of the diaphragm with manifold vacuum maintains a constant fuel pressure drop across the fuel injectors. Fuel pressure is high when engine vacuum is low. Excess fuel is bypassed through the fuel pressure regulator and returned through the fuel return line to the fuel tank.
Fig. 73: Fuel Pressure Regulator
Courtesy of FORD MOTOR CO.


http://www.2carpros.com/forum/automotive_pictures/266999_reg_2.jpg


Dave H
Feb 22, 2009.