The pressure reducing valve (fuel pressure regulator) is a container separated by a diaphragm on which is attached a valve that closes the fuel drain hole under the action of a spring.
The pressure reducing valve maintains a constant pressure in the power system of about 0.3 MPa.
The upper part of the pressure relief valve is connected to the receiver with a vacuum hose.
When the pressure drop in the receiver is not higher than 0.3 MPa, the valve is closed and the pressure in the supply system rises.
When the fuel pressure reaches more than 0.3 MPa, the membrane bends, opening a hole, and excess fuel is drained into the fuel tank.
As soon as the fuel pressure drops to 0.3 MPa, the membrane returns to its original position and closes the fuel drain hole.
Replacing the pressure relief valve
- Reduce the pressure in the power system if the engine has just been stopped.
- Disconnect the wire from the negative terminal of the battery.
- Remove the engine fuel line.
Disconnect fuel drain hose 1 and vacuum hose 4 from pressure reducing valve 3.
Unscrew the two fastening bolts 2 and remove the pressure reducing valve 3 from the engine fuel line.
Install the new valve in reverse order.
Let's look at this operation in more detail:
Relieve the fuel pressure, to do this:
With the ignition off, remove the fuse box cover and take out the fuel pump fuse F9.
Start the engine and let it exhaust the gasoline that is under pressure in the system.
After the engine stalls, turn off the ignition and replace the fuse.
Disconnect the negative terminal of the battery
Remove the fuel rail, to do this:
Disconnect the idle air control connector
Use a screwdriver to loosen the clamp of the air supply hose to the throttle body
Remove the air supply duct and the air damper drive cable from the throttle pipe
Use a screwdriver to loosen the clamp of the lower (outlet) hose of the idle air regulator.
Use a screwdriver to loosen the clamp and remove the crankcase ventilation system hose.
Use a screwdriver to loosen the clamp and remove the brake booster hose.
Use a screwdriver to loosen the clamp and remove the fuel pressure regulator hose.
Using a 13mm wrench, unscrew the nut securing the end of the ground wire to the first stud of the intake manifold.
In the same way, disconnect the wire from the last stud of the intake manifold.
Then, unscrewing the remaining nuts of the intake manifold studs with a 13mm wrench, remove the receiver.
Use a screwdriver to loosen the clamp of the supply hose to the ramp
Remove the supply hose from the fuel rail fitting.
Using a screwdriver and loosening the clamp, remove the crankcase ventilation hose from the idle air system pipe.
Use a screwdriver and loosen the clamp to remove the drain hose from the fuel pressure regulator fitting.
Using a 10mm wrench, unscrew the two screws securing the fuel rail to the intake manifold and remove the rail.
Use a screwdriver to unscrew the two screws securing the regulator to the ramp.
We install the new regulator in the reverse order, making sure that the sealing collar is put on its fitting.