2001 BMW 525i fuel filter

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130-68
Fuel Injection
0
4 The ME 7.2 uses a non-return fuel rail. The fuel pressure reg-
ulator is integrated into the fuel filter.
I iY.,lii,in
4 The M62 TU engine uses a continuously variable VANOS
system at each intake camshaft. This system enhances en-
gine performance and reduces tailpipe emissions. Both cam-
shafts are adjusted simultaneously within
20" (maximum) of
the camshafts rotational axis. This equates to a maximum
span of
40°crankshaft rotation.
regulalor from luel pump
NOTE-
The fuel filter is available as a replacement part without the
fuel pressure regulator. When replacing the fuel filter, trans-
fer the fuel pressure regulator from the old
filter to the new fil-
ter.
Engine idle speed control is a function of the EDK. The M62
TU engine does not use a separate idle control valve.
Mmn CON,ROL
EML
< The M62 TU engine uses an electrically controlled throttle
valve called EDK. The throttle plate is positioned by a DC
gear reduction motor based on inputs signals to the ECM
from the pedal position sensor (PWG).
When the accelerator pedal is moved, the PWG provides a
change in the monitored signals. The ME
7.2 control module
compares the input signal to a programmed map and appro-
priately activates the EDK motor via proportional pulse width
modulated control signals. The control module self-checks its
activation of the EDK motor via the EDK feedbaclc
potentiom-
eters.

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130-70
Fuel Injection
ECM relay
--
CAUTION-
Relay positions can vary Be sure to confirm relay position by
identifying the wiring in the
socl(et using the wiring diagrams
in ELE Electrical Wiring Diagrams.
Working in right rear of engine compartment:
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(B).
Rotate duct inward (arrow) to unlock from bulk head and
remove duct.
Release spring
loclt (C) to remove lower filter housing.
Slide filter housing away from inner fender to remove.
- Remove electrical box (E-box) cover fasteners and remove
cover.
4 With ignition off, remove main relay (arrow) in electronics
box (E-box) at right rear of engine compartment.
NOTE-
Relay locations can vary Confirm relay identification by
matching wiring colors and terminal numbers.
4 Check for voltage at terminal 6 of main relay socket (30-red
wire).
If battery voltage is present, continue testing.
If battery voltage is not present, check large red wire in re-
lay socltet. See ELE Electrical Wiring Diagrams.
- Reinstall relay and turn ignition on. Gain access to underside
of relay socket and check for ground at terminal
4 (85-brown
wire).
If ground is present, continue testing.
If ground is not present, switched ground signal from ECM
is missing. Check wire between ECM and relay.
- With ignition on and relay installed, check for battery voltage
at terminal
2 (87-redlwhite wire).
If battery voltage is present, relay has energized and is
functioning correctly.
If battery voltage is not present and all earlier tests are OK.
relay is faulty and should be replaced.

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( Mass Air Flow Sensor
1" Intake air temp. (NTC)
Sensor qround
Reference voltage . . . -., f fitr mass signal I
Fuel Injection I
Release fuel injector locking clips (arrow).
- Remove fuel injector loom boxes and lay to one side.
- Remove 4 fuel rail mounting fasteners.
4 Disconnect fuel line at quick-disconnect. To disconnect,
press in plastic collar (arrow) and separate fuel line.
WARNING -
Fuel may be expelled underpressure. Do not srnol(e or work
near heaters or
other fire hazards. Keep a fire extinguisher
handy. Before disconnecting fuel hoses, wrap a cloth around
fuel hose
to absorb anv leakinq fuel. Plug all open fuel lines.
- Lifl fuel rail and injectors straight up to remove.
- lnstallation is reverse of removal. Use new injector seals and
clamps during installation.
Mass air flow (MAF) sensor,
removing and installing
4 The MAF sensor is provided with operating power from the
ECM relay. Based on intake air mass, the MAF sensor gen-
erates a varying voltage (approx. 0.5
- 4.5 vdc) as an input
signal
back to the ECM. A separate intalte air temperature
sensor is not used.
- Removing MAF sensor:
Remove upper air filter housing locking clips
Unscrew and remove sensor harness.
Disconnect air temperature sensor harness.
Loosen hose clamp.
Remove upper filter housing with sensor.
- lnstallation is reverse of removal

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This repair group covers service information specifically for the fuel supply system. Information on the fuel injection sys-
tem is covered in
130 Fuel Injection.
In the descriptions and procedures given below, engine and
engine management (DME) systems are referred to by man-
ufacturer code. If necessary, see
100 Engine-General for
model year, engine code, and DME applications.
NOTE-
Fuel filter replacement is covered in 020 Maintenance,
Special tools
Some of the procedures in this group require the use of
special tools.
I( Fuel line clamp 13 3 010 (Tool No. BMW 13 3 01 0)
4 Fuel pressure gauge T-fitting with shut-off valve
(Tool No. BMW 13
5 220)

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Fuel Tank and Fuel Pump
Evaporative system troubleshooting
- Start by accessing diagnostic trouble codes (DTCs) using a
BMW or BMW compatible aftermarket scan tool.
For purposes of OBD
II emissions compliance, the DME
system sets a diagnostic trouble code (DTC) when it de-
tects a leak that is equal or larger than minimum
lealc
sensed by system.
Malfunction Indicator Light (MIL) is illuminated upon sec-
ond recurrence of fault. See OBD On-Board Diagnostics.
- When leak testing, observe following conditions to obtain
plausible results:
Fuel tank
'1, to 'I., full.
0 Vehicle parked for at least 2 hours to allow fuel to reach
room temperature.
Ideal fuel temperature is 10"- 20°C
(50"
- 68" F).
Do not refuel immediately before
lealc test.
- If a leak is detected, check the following areas:
* Fuel filter cap (leaking or off).
Fuel tank ventilation lines leaking at fuel
tank or activated
carbon canister.
i
Tank ventilation valve leaking (in engine compartment).
Fuel level
sensorlfuel pump cap leaking.
Evaporative system component replacement is covered later
in
th~s group in Fuel Tank and Fuel Lines.

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Fuel Tank and Fuel Pump
Fuel delivery,
testing
Checitino fuel delive~ is a fundamental oart of troubleshoot- .. ing and diagnosing thk DME system. ~ukl pressure directly
influences
fuel delivery. An accurate fuel pressure gauge will
be needed to make the tests.
There are two significant fuel deliveryvalues to be measured:
* System pressure - created by fuel pump and maintained
by pressure regulator
Residual pressure
- pressure maintained in closed sys-
tem after engine and fuel pump are shut off
if proper system pressure and residual pressure are present,
also check for problems in fuel delivery volume, which can be
affected by restrictions such as clogged fuel filter or fuel pick-
up port in the fuel tank.
System pressure, testing
1. Fuel pressure regulator outer seal
4 System pressure is created by the fuel pump and maintained
2. Vacuum line connection.
3. Fuel pressure regulator Inner seal.
4. Fuel flow back to fuel tank.
5. Fuel flow from fuel pump.
Fuel pressure
regulator
Fuel pressure regulator locations
M52 In fuel injector rail, in engine
compartment
M52 TU In 312 way valve, below vehicle under
driver seat
by the pressure
regulator. System pressure is not adjustable.
M54 In fuel filter
M62 to 9/97 In fuel injector rail, in engine
compartment
M62 from 9/97 to 9/98 In 312 way valve, below vehicle under
driver seat
M62 TU from 9/98 In fuel filter, below vehicle under driver
seat

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.- .
Fuel Tank and Fuel Pump
- To reinstall:
Use new sealing ring at tank collar.
* Align tab of sending unit with matching recess in opening
of tank.
Be sure that fuel line connections point in same direction
as they came out.
Reconnect harness connector and hose.
Fill tank and check for leaks by running engine.
Install access cover and its mounting fasteners.
CAUTIOI\C
After finishing repairs but before starting engine, be sure
there is at least
5 liters (1.5 gallons) of fuel in the tank. The
NOTE-
It is common practice to replace the fuel filter when the fuel
pump
unit is replaced. See 020 Maintenance.
Tightening torque
Tank collar locking ring to tank 35 Nm (26 lb-ft)
Fuel level sender (left side),
removing and installing
The procedure for removing and replacing the left side fuel
level sender is
simllar to that used for the r~ght side. There is
no fuel pump on the left side.
- Remove rear seat lower cushion by lifting off catches at front.
- Expose left side access cover:
- Peel forward lip of carpet.
Release rubber grommet from center of access cover
insulation.
Peel back insulation at
perforations to expose fuel tank
access cover.
Remove cover to expose electrical harness connector.
WARNING-
Fuel may be spilled. Do not smoke or work near heaters or
other fire hazards.
When disconnecting fuel hose, wrap shop rag around
end of hose to prevent spray of fuel under pressure.

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Fuel Tank and Fuel Pump 1
Activated carbon canister I fuel tank leak
detection unit
(LDP or DMTL), removing . . -
and installing
- Raise rear end of car and support safely.
CAUTION-
Make sure the car is stable and well supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose.
A floor jack is not adequate support.
- Remove left rear wheel and inner fender panel
Remove carbon canisterlfuel tank leak detection unit
(V-8 model shown):
Disconnect electrical harness connector
(A) from fuel tank
leak detection unit.
Pinch and remove quick-disconnect fittings at intake line to
air filter housing
(5) and hose to expansion tank (C).
* Remove mounting clamp and lower canister with fuel tank
leak detection unit.
Installation is reverse of removal.
Tightening
torques
Hose clamp 8 - 13 mm dia. 2 Nrn (18 in-lb)
Hose clamp
13 - 16 rnm dia 3 Nm (27 in-lb)
Running losses (312-way) valve,
removing and installing
The running losses (312-way) valve is located under the car
beneath the driver's seat, just ahead of the fuel filter. A protec-
tive covershieldsfuel system components from road hazards
and dirt.
The engine control module
(ECM) controls the operation of
the 312-way valve (pulse-width modulated). On engine start
up, the valve solenoid is energized for 20 seconds in order to
supply full fuel volume to the fuel rail.
After20 seconds, the
solenoid is deactivated and sprung closed (the bypass is
opened). This reduces the amount of fuel circulating through
the fuel rail and diverts the excess to return to the fuel tank
through the fuel pressure regulator.
The fuel injectors are supplied with pressurized fuel, but ex-
cess fuel is diverted to the fuel tank without first passing
through the fuel rail. This prevents the excess fuel from ab-
sorbing heat in the engine compartment, thus lowering the
temperature and amount of vaporization in the fuel tank.