?where is the fuel pressure regulator placed - 2000 BMW 325ti

A faulty fuel pressure regulator may result in engine misfires, reduction in power, poor acceleration, and a decrease in fuel efficiency. That said, the symptoms can also take place owing to other mechanical issues.

The Fuel Pressure Regulator is attached to the fuel pump and that whole assembly is located in the gas tank, beneath the rear seat. AFAIK there is only the one unit, not one for each bank. You can test to see if you have sufficient fuel pressure at the fuel filter.

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Do you know what fuel pressure regulator is ? These like to leak when they get older !
The cartridge type fuel pressure regulator (1) is a diaphragm-operated relief valve (6) with fuel pump pressure on one side, and regulator spring (2) pressure, and intake manifold vacuum on the other side. The regulators function is to maintain a constant fuel pressure across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops.
The cartridge regulator is serviced as a separate component. When servicing the fuel pressure regulator, insure that the O-ring backup, (3) large O-ring, (4) filter screen, (5) and small O-ring (7) are properly placed on the pressure regulator.
It's located on the fuel injector fuel rail !


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Check fuel pressure at test port, fuel filter and inspect the whole fuel line for kinks & crimps. If that doesn't work disconnect the fuel filter then use high pressure air to blow from the pressure regulator to the removed filter to ensure that the line is clear and open. Hook everything back up and check for pressure.

Fuel Pressure Regulator - REMOVAL & INSTALLATION
(see Figure 1)

1. Disconnect the negative battery cable.
   
2. Relieve fuel system pressure.
   
3. Disconnect the ignition coil.
   
4. Remove the upper intake manifold.
   
5. Disconnect the vacuum line to the regulator.
   
6. Remove the snapring from the regulator housing.
   
7. Place a towel under the regulator to absorb any spilled fuel and remove the pressure regulator from the fuel rail socket.
   
8. Remove the pressure regulator from the fuel rail.
   
9. Remove the pressure regulator O-ring filter, O-ring backup and O-ring and discard them.

Fig. 1: Exploded view of the pressure regulator assembly-MFI systems

To install:

1. Before installing the O-rings, lubricate them with clean engine oil and install them on the regulator inlet as a complete assembly.
   
2. Install the snapring retainer into the slot on the regulator housing.
   
3. Connect the vacuum line to the regulator.
   

Ensure that the retainer is properly seated in the slot in the regulator housing. Pull on the regulator to make sure that it is properly seated.

1. Connect the negative battery cable.
   
2. Turn the ignition ON for 2 seconds and then turn it OFF for 10 seconds. Again turn the ignition ON and check for leaks.
   
3. Install the manifold plenum.

Hope this helps.

1. First, you will need to depressurize your fuel system. Remove the Fuel Pump Relay, start the vehicle and run until it shuts off, should only take a few seconds.
2. The Fuel Pressure Regulator is held in place on the Fuel Rail using a Retaining Ring, or Snap Ring.
3. You will need to remove the Vacuum Hose connected to the Fuel Pressure Regulator before you remove the retaining ring.
4. You need a pair of Snap Ring Pliers to remove this retaining ring.
5. Once the retaining ring is removed, slide the old Fuel Pressure Regulator out, and install the new one. Lubricate the O rings on the new part and the fuel line before assembly.
6. After reinserting the Snap Ring, ensure that it is snapped in place completely.
7. Reinstall the Vacuum hose and reconnect your Fuel Pump Relay. Turn the Ignition to On, and check for leaks around the Fuel Pressure Regulator.
8. If no leaks are found, proceed to start the vehicle.

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Fuel Pressure Regulator Removal & Installation To Remove:

1. Spread tangs on pressure regulator retainer.
2. Pry fuel pressure regulator out of housing.
3. Ensure both upper and lower O-rings were removed with regulator.

To Install:

1. Lightly lubricate the O-rings with clean engine oil and place them into opening in pump module.
2. Push regulator into opening in pump module.
3. Tabs hold regulator in housing.

1. Place a shop towel under the fuel pressure regulator,

then relieve fuel pressure

2. Disconnect the vacuum hose and fuel return hose.
3. Remove the two 6 mm retainer bolts.

Fuel Filter Removal & Installation NOTE: A combination fuel filter and fuel pressure regulator is used on all gas powered engines. It is located on the top of the fuel pump module. It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter is also part of the assembly.
To Remove:

1. Before servicing the vehicle, refer to the precautions at the beginning of this section.
2. Release fuel pressure
3. Remove or disconnect the following:
   • Fuel Tank refer
   • Fuel tank and remove the purge line and vent line.
   • Fuel line from pressure regulator. Fuel Pressure Regulator Locking Tab
     
     
   • Pressure regulator by pushing the locking tab in from locking slot and turning pressure regulator to unlock it.
   • Pull regulator straight up.

To Install:

1. Push regulator down and into place.
2. Turn fuel pressure regulator to lock it in place. Make sure take the locking tab is in the locking slot.
3. Install or connect the following:
   • Fuel line to regulator
   • Fuel pump electrical connector into hole in the body.
   • The purge and vent lines.
   • Tank into position and install tank straps.
   • The fuel filler tube and tighten the clamp.
   • The stabilizer bar and install bolts.
4. Lower vehicle.
5. Install or connect the following:
   • The fuel pump electrical connector that is in the rear seat.
   • The rear seat.
   • The battery cable.
6. Fill fuel tank. Use the DRB scan tool to pressurize the fuel system. Check for leaks.

Keep in mind that you have several components there:
- Fuel Pump Sender Assembly,
- Fuel Pressure Regulator,
- Fuel Rail Assembly, and
- Fuel Injectors.

1.- Fuel Pump (Sender Assembly) - TESTING
Refer to the accompanying charts for fuel pump diagnosis and testing.

The fuel injection system remains under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.



Fig. 3.1L engine OBD system check to be done before fuel pump relay circuit diagnosis




Fig. 3.1L engine fuel pump relay circuit diagnosis (1 of 2)




Fig. 3.1L engine fuel pump relay circuit diagnosis (2 of 2)




Fig. View of the fuel pressure test port (Schrader valve)-3.1L engine

A - 3.1L engine fuel system pressure test (1 of 4)
B - 3.1L engine fuel system pressure test (2 of 4)
C - 3.1L engine fuel system pressure test (3 of 4)
D - 3.1L engine fuel system pressure test (4 of 4)



Fig. The fuel pump/fuel sender module assembly is mounted in the fuel tank


2.- Fuel Pressure Regulator - REMOVAL & INSTALLATION

(the fuel pressure regulator, which is located on the fuel rail assembly)

NOTE: Before removing the fuel regulator assembly, place a clean shop towel under the regulator to catch any fuel drips

1. Properly relieve the fuel system pressure.
2. If not done already, disconnect the negative battery cable.
3. On the 3.1L engine, remove the intake manifold plenum, as outlined in .
4. On the 2.4L engine, remove the fuel rail. Refer to procedure earlier in this section.
5. Detach the vacuum line from the regulator.
6. Place a shop towel under the regulator to catch any fuel that may drip out. Unfasten the fuel pressure regulator retaining screw, then remove the regulator by twisting and pulling it from the fuel rail.
7. Remove and discard the O-ring seal. Inspect the filter screen for contamination and replace if necessary.
   

To install:

1. Prior to assembling the pressure regulator to the fuel rail, lubricate the new rail-to-regulator O-ring seal with clean engine oil.
2. Place the O-ring on the pressure regulator and install the pressure regulator to the fuel rail.
3. Install the retainer or coat the regulator mounting screws with an approved thread locking compound and secure the pressure regulator in place. Tighten the mounting screw to 76 inch lbs. (8.5 Nm).
4. If removed, install the fuel rail assembly to the engine.

WARNING The fuel return pipe must be connected before tightening the regulator retaining screw to prevent the regulator from rotating. Rotation of the regulator could damage the retainer and spacer bracket and lead to a fuel leak at the regulator inlet.

1. Connect the fuel feed line and return line to the fuel rail assembly, use a backup wrench on the fittings to prevent turning.
2. Attach the vacuum line to the regulator.
3. On the 3.1L engine, install the intake manifold plenum.
4. Connect the negative battery cable. Turn the ignition to the ON position for two seconds, then turn it to the OFF position for ten seconds. Turn again to the ON position and check for fuel leaks.

continue...

Release fuel pressure by removing fuel pump relay and turning engine over to release pressure. Place a rag to catch any fuel under regulator Fuel pressure regulator has a locking clip pry clip off remove vacuum line pull regulator out with twisting motion,replace fuel pressure regulator install clip connect vacuum line install relay. Check for leaks,your done.