Valve BMW 525i 2001 E39 Workshop Manual

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Fuel Tank and Fuel Pump
Fuel pump
The electric fuel pump is mounted in the fuel tank in tandem
with the right side fuel level sender. The fuel pump delivers
pressurized fuel to the fuel injection system.
A pressure regu-
lator maintains system pressure. The quantity of fuel supplied
exceeds demand, so excess fuel returns to the fuel tank via a
return line. See
130 Fuel Injection for more information.
NOTE-
Fuel pump removal procedures are given under Fuel level
sender (right side) and fuel pump, removing and install-
ing.
Fuel tank evaporative control system
Evaporative control, also referred to as running losses con-
trol, is designed to prevent fuel system evaporative losses
from venting into the atmosphere.
The components of this system allow control and monitoring
of evaporative losses by the on-board diagnostic
(OED II)
software incorporated into the engine control module (ECM).
NOTE-
1997 V-8 models (540i) with Bosch DME M5.2 are not
equipped with an
OBD I1 running losses monitoring system.
Fuel tank evaporative
control system
(models with
DME MS42.0)
4 The main components of the evaporative control system and
their functions:
Fuel overflow
tank acts as a liquidlvapor separator
Carbon canister stores evaporated fuel.
Plumbing ducts vapors from fuel tank to canister and from
canister to intake
manifold.
- Carbon canister purge valve is controlled by enginecontrol
module (ECM).
Running losses or 312-way valve (not shown) shunts ex-
cess fuel volume directly
back to fuel tank before it circu-
lates through injector fuel rail (models with Siemens MS42
or Bosch M5.2.1 engine management only).
Leak detection unit (LDP or DMTL) pressurizes fuel
tank
and evaporative system to monitor system leaks (models
with Siemens MS42 or Bosch M5.2.1 and later).
Leak detection systems vary among models and years, and
are further described in
130 Fuel Injection.
NOTE -
"3/2-way valve", 'tunning losses valve" and "fuel changeover
valve" are used interchangeably
in BMW technical literature.

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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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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 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
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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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.

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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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Exhaust system1
Exhaust manifold removal procedures are organized accord-
ing to engine code. If necessary, see
100 Engine-General
for engine code and application information.
Exhaust manifolds, removing and installing
(M52 engine)
4 Exhaust manifolds for the M52 engine.
Always use new retaining nuts and gaskets when removing
and installing the exhaust manifolds.
- With exhaust system cold, raise and support car for access
to exhaust system.
WARNING -
Do not work under a lined car unless it is solidly supported on
jack stands designed for that purpose. Never work under a
car that is supported solely by a jack.
- Disconnect secondary air check valve and pipe from exhaust
manifold.
- Unbolt front exhaust pipe@) from exhaust rnanifold(s)
- Remove exhaust support bracket from transmission.
- Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
NOTE-
On cars with oxygen sensors mounted in the exhaust mani-
folds, use care when removing manifolds.
To be safe, remove
the sensors from the manifolds before removing manifolds.
- Installation is reverse of removal
Coat exhaust manifold mounting studs with copper paste
before installing new nuts.
Install manifold gaskets with arched side facing manifolds.
Tightening torque
Exhaust manifolds
to cylinder head 20 Nm (15 ft-lb)

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180-6
Exhaust System
Exhaust manifolds, removing and installing
(M52 TU and M54 engines)
I Exhaust manifolds with converters I 4 The exhaust manifolds incorporate the catalytic converters.
Two precatalyst and two post-catalyst oxygen sensors are
mounted in the exhaust manifold assembly.
Under normal conditions, the catalytic converters do not re-
quire replacement unless damaged. Always use new retain-
ing nuts and gaskets when removing and installing the
exhaust manifolds.
I\
1 4 Using engine support equipment (BMW special tools 00 0
200. 00 0 201. 00 0 202.00 0 204.00 0 208 or equivalent).
connect to
lifting eye on front of engine. Rhise engine approx.
/I 1
5 mm (IH in).
With exhaust system cold, raise and support car for access
to exhaust system.
WARNING-
Do not worlc undera liftedcar unless it is solidly supported on
jack stands designed for that purpose. Never worlc under
a
car that is supported solely by a jaclc.
in order to avoid damaging oxygen sensors:
- Detach oxygen sensor harness connectors,
Remove oxygen sensors from exhaust manifolds as de-
scribed later in this group.
Unbolt and remove secondary air
checkvalve and pipe from
right front of cylinder headlexhaust manifold.
Working underneath car, unbolt front exhaust pipes from ex.
haust manifolds.
With engine supported from above, remove right engine
mount
bracket and right engine mount (arrow).
Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
CA UTIOG
Take care tliat the front and rear oxygen sensor connectors
are not mixed up.
-