fuel cap BMW 525i 2001 E39 Owner's Guide

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I Fuel Tank and Fuel Pump --
Fuel pressure gauge, installing
(6-cylinder models)
4 Remove fuel rail cover by prying off trim covers (arrows) and
removing nuts.
4 If equipped, remove schraeder valve cap (arrow). Blow fuel
back through feed line using a brief burst of compressed air
(maximum
3 bar or 43.5 psi).
WARNING -
Fuel in fuel line is underpressure (approx. 3 - 5 bar or 45 -
75psi) andmay be expelled underpressure. Do not smoke
or work near heaters or other fire hazards. Keep a fire ex-
tinguisher handy Before disconnecting fuel hoses, wrap a
cloth around fuel hoses to absorb any leaking fuel. Catch
and dispose of escaped fuel. Plug all open fuel lines.
Always unscrew the fuel tank cap to release pressure
in the tank before working on the tank or lines.
4 Attach fuel pressure gauge to BMW special tool 13 5 220
(T-fittlng) or equivalent and attach to schraeder valve.
WARNING -
The fuel pressure gauge must be securely connected to pre-
vent it from
coming loose underpressure.
CAUTION-
When using the BMWspecial tool, use care when turning the
T-handle in to open the schraeder valve. Screw the handle in
just until the schraeder valve opens. Turning the handle in too
far will damage the schraeder valve.
NOTE-
* The schraeder valve must be opened to the fuel pressure
gauge connection. Either remove the valve using a stan-
dard tire valve removal tool or use the BMW special tool
15 5 220.
* The fuel pressure gauge should have a minimum range of
0 to 5 bar (0 to 75 psi).
- For vehicles without the schraeder valve on the fuel rail, at-
tach the fuel pressure gauge in line with the fuel supply line
to the fuel rail.

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Fuel Tank and Fuel Pump
Fuel pressure gauge, installing
(V-8 models)
Remove engine cover by pressing down on pins (arrows) to
release cover locks.
4 Disconnect and remove fuel supply line from lefl side of fuel
rail by sliding
loclting collar in (arrows) and pulling lines
apart.
NOTE-
* ME2 TU and MS43 vehicles (1999 and later models) use a
non-return fuel line with only one line to the fuel
rafl.
BMW uses three styles of fuellfne connections; a one-use
clamp, a locking fitting that uses
BMWspeclal tool 16 1 050
to release, and a quick release sleeve (above) that discon-
nects the line when depressed.
WARNING -
* Fuel In fuel line is under pressure (approx. 3 - 5 bar or 45 -
75psi) and may be expelled underpressure. Do not smoke
or work near heaters or other fire hazards. Keep a fire ex-
tinguisher handy. Before disconnecting fuel hoses, wrap a
cloth around fuel hoses to absorb any
lealiing fuel. Catch
and dispose of escaped fuel. Plug all open fuel lines.
Always unscrew the fuel tank cap to release pressure
in the tank before workina on the tank or lines.
< Install inline fuel pressure gauge.
WARNING -
The fuel pressure gauge must be securely connected to pre-
vent it from coming loose underpressure.
NOTE-
The fuel pressure gauge should have a minimum range of 0
to 5 bar (0 to 75 psi).

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Fuel Tank and Fuel Pump
4 Relieve system pressure and attach a fuel pressure gauge as
described in Fuel pressure gauge, installing (6-cylinder
models) or Fuel pressure gauge, installing
(V-8 models).
WARNING-
Fuel in fuel line is under pressure (approx. 3 - 5 bar or 45 -
75psi) and may be expelled underpressure. Do not smoke
or
worlc near heaters or other fire hazards. Keep a fire ex-
tinguisher handy Before disconnecting fuel hoses, wrap a
cloth around fuel hoses to absorb any
leaking fuel. Catch
and dispose of escaped fuel. Plug all open fuel lines.
Always unscrew the fuel tank cap to release pressure
in the tank before
working on the tank or lines.
- Operate fuel pump as described in Operating fuel pump for
tests. Compare fuel pressure to specifications in accompa-
nying table.
Fuel pressure specification
All E39 vehicles 3.5 +0.2 bar (50.76 i2.9 psi)
- If pressure is low, repeat test while gradually pinching off re-
turn hose to fuel tank. Pressure should rise rapidly. If not, fuel
pump is most likely faulty. If pressure rises, the fuel pressure
regulator is most
likely faulty.
- If pressure is too high, checlc return line from pressure regu-
lator to tank. Check for
ltinks in hose. If no faults can be
found, pressure regulator is most likely faulty.
CAUTION-
The fuel pump is capable of developing a higher pressure
than that regulated by the pressure regulator. In the event the
fuel pump checlc valve is faulty (stuck closed), male sure the
I fuel pressure does not rise above 6.0 bar (87psi). Damage
to the fuel lines or fuel system components could result.
- Reassemble engine, noting the following:
Remove fuel pressure gauge and fittings.
Replace schraeder valve, if removed
Replace fuel pump relay.
Replace fuel filler cap.
Residual pressure, testing
For quick restarts and to avoid vapor lock when the engine is
hot, the fuel injection system retains fuel pressure after the
engine is shut off. This residual pressure is primarily
rnain-
tained by the fuel pressure regulator and a checlc valve at the
fuel pump
outlet.

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. .
I Fuel Tank and Fuel Pump I
4 Relieve system pressure and attach afuel pressure gauge as
described in Fuel pressure gauge, installing (6-cylinder
models) or Fuel pressure gauge, installing
(V-8 models).
WARNING -
Fuel in fuel line is underpressure (approx. 3 - 5 bar or45 -
75psi) and may be expelled underpressure. Do not smoke
or work near heaters or other fire hazards. Keep a fire ex-
tinguisher handy. Before disconnecting fuel hoses, wrap a
cloth around fuel hoses to absorb any leaking fuel. Catch
and dispose of escaped fuel. Plug all open fuel lines.
. Always unscrew the fuel tank cap to release pressure
in the tank before working on the tank or lines
- Start engine allow it to run for approximately one minute.
Note fuel pressure reading.
- Observe fuel pressure reading after approximately 20 mln-
utes. The pressure should not drop more than 0.5 bar from
system pressure listed in fuel pressure specifications in ac-
companying table.
Fuel pressure specification
Ail
E39 vehicles 3.5 i-0.2 bar (50.76 i2.9 psi)
- When finished, disconnect pressure gauge and fitting, and
replace schraeder valve, if removed.
- If fuel system does not maintain pressure:
Visually check for leaks in fuel lines and unions,
Check for leaking
injector(s).
Check for faulty fuel pump check valve.
- To test fuel pump check valve:
Repeat residual pressure test.
Immediately aftershutting off engine, pinch off fuel delivery
line using a fuel hose pinch clamp (BMW
13 3 010 or
equivalent).
If pressure is now maintained, fault is most likely at fuel
pump check valve.
If pressure again drops below specifications, fault is most
likely in fuel pressure regulator.

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.-
err- .- Fuel Tank and Fuel Pump
FUELPUMP AND FUELLEVELSENDER
E39 models use a two-lobed fuel tank. Each lobe of the tank
has its own fuel level sending unit. Each sender has a float
connected to a variable resistance wipercontact. To equalize
fuel level between the two
tank lobes, a siphon pump is in-
stalled in the left lobe.
When replacing asender or fuel pump, always replace hose
clamps,
gasltets and O-rings.
WARNING
-
When removing the fuel level sender or the fuel pump, the
fuel tank should be drained to
1/4 capacity or below as de-
scribed later in this repair group.
NOTE-
The compensating siphon pump maintains the fuel level be-
tween the right and left tank lobes. If fuel level sender resis-
tances are not approximately the same on left and right,
remove the senders and visually inspect the level in each
lobe. If the levels are different, check the siphon pump.
Fuel level sender resistances
Float position
l~est results (Q
Down (empty) 150- 70
Up (full) 1401 -415
Fuel level sender (right side) and fuel
pump, removing
and installing
- Drain fuel from tank as described later.
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- To access top of fuel tank, remove rear seat lower cushion by
lifting front edge
off catches.

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--
I Fuel Tank and Fuel Pump
The plastic fuel tank is mounted underneath the center of the
car (underneath the rear seat). Mounted in the fuel tank are
the fuel pump and fuel level sending units. Connecting lines
for the evaporative emission control system and expansion
tank are also attached to the tank.
Fuel
tank capacity for E39 models
Tank capacity
70 liters (18.5 gal)
Reserve capacity
8 liters (2.1 gal)
Fuel tank, draining
Drain fuel tank into a safe storage unit using an approved fuel
pumping device.
WARNING-
# Before removing tank, be sure that all hot components,
such as the exhaust system, are completely cooled down.
Fuel may be spilled. Do not smoke or
work near heat-
ers or other fire hazards.
- Start engine and allow to run 10 - 15 seconds to fill fuel com-
pensating siphon assembly. This will allow both lobes of fuel
tank to he drawn off through fuel filler pipe,
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the batteg read the battery discon-
nection cautions given
in 001 General Warnings and Cau-
tions.
- Remove fuel tank filler cap
- Slide suction hose into filler neck about 130 cm (51 in.), twist-
ing as necessary. Withdraw fuel into storage unit.
- Monitor fuel level reduction in both lobes:
- Remove rear seat cushion and access both fuel tank send-
er harness connectors.
Use multimeter to measure resistance at both senders,
Resistance should drop as fuel level drops.
- If siphoning mechanism is faulty, drain left tank lobe sepa-
rately by removing sender cover and pumping fuel directly
out of left lobe.

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Fuel Tank and Fuel pump/
- Remove suction hose from tank filler neck carefully to avoid
damaging filler neck baffle plate.
CAUTION-
After finishing repairs but before starling engine, be sure
there is at least
5 liters (1.5 gallons) of fuel in tanlc. The fuel
pump will be damaged if run without fuel.
Fuel tank, removing and installing
- Remove fuel tank filler cap and drain tank as described
earlier.
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove rear seat bottom cushion. Peel forward lip of carpet
from beneath seat cushion and carefully peel back insulation
to expose fuel tank access cover on left and right sides. Re-
move covers.
Disconnect right side supply hose and
electr~cal harness
connector (arrows).
D~sconnect left side return hose and electrical harness
connector.
Working inside car, disconnect parking
bralte cable ends
from parking brake lever. See
340 Brakes.
Lift car and support safely.
Make sure the car is stable and
we/ supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose. A floorjaclc is not adequate support.
- Remove complete exhaust system and heat shield. See 180
Exhaust System.
- Remove drive shaft. See 260 Driveshaft

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160-25
Fuel Tank and Fuel pump1
The 312-way valve is also activated briefly if an engine misfire
is detected. This provides full fuel flow through the fuel rail to
determine if the misfire was caused by a lean fuel condition.
The valve is monitored by the ECM forfaults.
- Using BMW or compatible scan tool, read out fault memory.
See
OBD On-Board Diagnostics.
- Turn off ignition.
- Raise car and support safely.
CA UTIOW
Male sure the car is stable and well suppodedat all times.
Use a professional automotive lift
orjack stands designed for
the purpose.
A floor jack is not adequate support.
- Worlting under car beneath driver's seat, remove protective
panel from fuel filter and 312-way valve.
- Clamp off fuel lines at 312-way valve.
4 To remove 312-way valve (V-8 model shown):
Disconnect electrical harness connector
(A) from valve.
Remove vacuum hose
(B) from fuel pressure regulator.
* Remove hose clamps (arrows) and disconnect fuel lines.
Remove
M6 mounting nuts and lower 312-way valve.
WARNING-
Fuel will be spilled. Use shop rags to capture fuelas fuellines
are disconnected. Do not
smoke or work near heaters or oth-
er fire hazards.
- Installation is reverse of removal. Use new hose clamps
NOTE-
Install protective cover and seals correctly to keep moisture
and road dirt out of underbody fuel system components.
Tightening torques Hose clamps
8 - 13 mm dia.
2 Nm (18 in-lb)
Hose clamps
10 - 16 mm dia.
2 Nm (18 in-lb)
Hose clamps
18 mm dia. 3 Nm (27 in-lb)
Hose clamps 42
- 48 mm dia. 4 Nm 136 in-ib)

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INDEX 'tl
WARNING
Your common sense, good
judgemenl, and general alertness are
crucial to sale and successiul service
worlr. Belore attempting any work on
your
BMM be sure lo read 001
General Warnings and Cautions
and the
copyriglll page at the front 01
the manual. Review these warnings
and
caulions each lime you prepare
lo work on your BMW. Please also
read any warnings and cautions that
accompany
tile procedures in the
manual.
312-way valve (running losses)
see Fuel tank
Abbreviations, commonly used 600-14
ABS (antilock brake system)
see
Bral(es
A/C air distribution motors
see stepper motors (below)
blower final stage (resistor pack),
replacing
640-16
blower, removinglinslalling
640-1 5
compressor, replacing
640-24 condenser, replacing 64045
control panellmodule, removing1
installing
640-1 1
evaporakr, removinglinstalling 640-29
evaporator temperature sensor
640-12 expansion valve, removinglinstailing
640-27
IHKA/ IHKR system description 640-5
receiveridrier, replacing 640-26
stepper motors 640-1 3 ventilation microiilter, replacing
020-22. 640-17
see also Heating
Accelerator
iinlcage
see Maintenance
Activated carbon canister
see Fuel tank
ADS (auxiliary throttle valve)
130-57
Air compressor
330-44
Air conditioning
see
AIC
Air distribution (flap) motors
seeNC, stepper motors
Air filter see Maintenance
Air spring
300-6, 330-12
Airbag system (SRS)
2-stage
airbag 721-4
control module, replacing 721-7 driver airbag, removinglinstalling
721-8
iiead protection airbag 721-12 components 721-1 1
indicator
lighl721-4
passenger airbag, removinglinstalling
721-9 side-impact airbags crash sensor,
replacing
721-7
Airflow sensor see 130 under appropriate
fuel
injection system
Air pump
see 130 under appropriate fuel
injection system, secondary air
injection system
Air suspension
see Electronic height control
(EHC)
Alarm
see Anti-theft alarm
Alignment see
Wheei alignment
Aluminum suspension components
300-2
Antenna 650-6
Alternator see Battery, starter, alte rnator
Amplifier
650-4
Anti-theft alarm (DWA)
515-24 emergency disarming 515-31
Antifreeze (engine coolant)
see Maintenance
see also Cooling system
Antilock brake system (ABS) see Brakes
ASC see Brakes
ATF (automatic transmission fluid)
see Automatic transmission
see also Cooling systern
Automatic headlight adjustmenl
(LWR) see Lights
Automatic seat belt tensioner
720-4
Automatic shiftloclc
see
Gearshift
Automatic transmission
applications
200-3, 240-4
ATF 020-10, 200-4
capacity 240-8 checking 240-6
drainingifilling 240-7
heat exchanger 170-5
fluid pan and strainer 240-9 gearshift
see Gearshift
ID tag
200-3 range switch 610-6
removaliinstallation 240-10
steptronic see Gearshift
Auxiliary cooling fan
see
Coollng system, electric Ian
Auxiliary throttle valve (ADS)
130-57
Axle joint
see Drive axle
Back-up light switch
automatic transmission see Automatic transmission. range switch
- .~.~~~
manual transmission 230-8 -
- I

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2 INDEX
Battery, starter, alternator
alternator (generator)
121-10
6-cylinder engine, removingi
installing 121-15
M62 engine 121-16
M62 TU engine (water cooled)
121-18
battery
121-5 charging 121-9
safety terminal 121-3
testing 121-5 charging system, troubleshooting
121-12
starter
121-1 9
6-cylinder engine, removingi instaliinq 121-20 . V-8 engine, rernovinglinsialiing
121-21
solenoid, removinglinstalling
121-23 troubleshooting 121-19
see also Maintenance
Bearing, wheel
see Front suspension
see also Rear suspension
Belts see Maintenance, drive belts
Blade, wiper
see Wipers and Washers
Blower motor see
A/C
BMW emblem
see Exterior trim
BMW special tools 010-18 see also special tools section at
beginning
of each repair group
Body dimensions 400-2
interior features
400-9 salety and security 400-7
Body side molding
see Exterior trim
Bonnet see Engine hood
Boot see Trunk
Brake fluid
020-24, 340-8
Brake fluid pressure sensor
340-30
Brakes
ABS, ASC or DSC system
300-12
component replacement 340-26
ASCIDSC switch
see Switches
bleeding
bralces 340-8
brake booster 340-1 9 bralce Dads. caiioers and rotors ,., 340-1 1
descriotion 300-10
e~ectrdnic brake & stability 300-11
light switch
see Switches
master cylinder
340-16 pariking brake 340-22
troubleshooting 340-5
Bulbs see Lights
Bumper
lront 510-6 height, adjusting 510-12
rear 510-9
Bus system
600-4
Camber
320-33
Camshaft
removingiinslaiiing
M52 engine 116-12
M52 TU
/ M54 engine 116-1 9 M62 engine 11 6-39
wear
116-6
Camshaft position sensors
see ignition system
Camshaft timing chain
adjusting M52 engine
117-22
M52 TU I M54 engine 117-43
M62 engine 117-79 removinglinstalling
M52 engine 117-26
M52TU 1 M54 engine 113-46.116-
28
M62 engine 117-66
Capacities, fluid
020.10
Car rnemorvlicev memorv . . 600-10
see also Centrai
lociking
Carbon canister, activated
see Fuel
tank
Caster
320-33
Catalytic converter and oxygen sensor 020-19
see also Exhaust system: exhaust
manilolds
Cautions
001-3
CD changer
650-4
Center bearing, driveshaft
see Driveshait
Center brake light
sedan
630-13
Center console
513-3
Centrai body electronics (ZKE 111)
600-6
Central locking
car memoryiey memory 515.12 general module iunctions 515-2
remote entry (FZV) 515-8
remote lkey initialization 515-10 single lociddouble ioclk 515-6
switch 515-4
Chain
see Camshaft liming chain
Characteristic map (electrically heated) thermostat
see Electrically heated thermostat
Charging system
see Battery, starter, alternator
Cluster see instruments
Clutch fluid see Maintenance
hydraulics
210-4
mechanical 210-9
switch
see Switches, pedal ciuster
variations
210.10
Codes, fault OED-1
Coil
see Ignition system
Coil spring
see Front suspension
see also Rear
suspe nsion