2001 BMW 525i manifold

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130-36
[~uel Injection
4 Remove nuts and bolts (arrows) retaining wiring harness to
throttle housing.
- Working at throttle housing, turn harness plug countercloclc
wise and remove.
4 Working at side of intake manifold, disconnect electrical bar-
ness connectors:
Idle control valve (A)
Intake manifold resonance valve (B)
- Disconnect electrical harness connectors at oil pressure
sender and oil temperature sender at base of oil filter hous-
ing.
4 Remove dipstick guide tube:
Disconnect wiring harness brackets from tube
(A)
Unclip fuel lines from tube (B).
Remove lower guide tube mounting bolt (C).
Pull out dipstick guide tube.

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-.
Fuel Injection 1
4 If necessary, disconnect electrical harness connector at fuel
tank venting valve (A). Disconnect hose at quick disconnect
fitting
(arrow).
< Worlting at throttle housing, turn harness plug counterclock-
wise and disconnect. Remove throttle assembly mounting
fasteners
(arrows) and pull assembly off manifold.
- Installation is reverse of removal.
0 Replace sealing ring between throttle assembly and intake
manifold.
Reattach throttle assembly harness connector with care.
0 Arrow on fully tightened connector must line up with corre-
sponding arrow on throttle assembly housing.
- Use BMW scan tool to reset ECM adaptation values.

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130-51
Fuel Injection
Oxygen sensors, checking
The oxygen sensor provides an input voltage signal [0.2 vdc
(lean) to 0.8 vdc (rich)] to the
ECM based on the oxygen con-
tent in the exhaust gas. To generate voltage, the sensor tem-
perature must exceed 575"
F (300" C). Therefore the sensor
is electrically heated.
NO JE -
The test given below is not a conclusive test of oxygen sen-
sor efficiency and does not test how the oxygen sensor re-
acts to changing conditions. Pin numbers and wire colors
can vary Always check the wiring diagrams to confirm wire
color and pin assignment.
0 The oxygen sensorconnectorplugs are locatednext to the
catalytic converters.
With connector attached to sensor, connect digital voltmeter
between
A and B wires in connector.
WARNING -
Exhaust manifolds andpipes can be hot enough to cause se-
rious burns. Wear suitable heavy gloves and other appropri-
ate protection.
NOJE-
Connector style may vary depending on system application.
Consult wiring diagram for system-specific wiring. See
ELE
Electrical Wiring Diagrams.
Start engine.
A fluctuating voltage signal should show on the
meter.
If voltage is incorrect, turn engine off and check pre-
heater circuit as described below.
NOJE-
To check sensor response to lean and rich mixtures, create
an air leak.
Oxygen sensor
voltage at idle
- Connect digital voltmeterbetween sensor heaterwires (white
wires,
C and D). Start engine and check for battery voltage.
If voltage is not present, check oxygen sensor heater fuses.
0.2 to 0.8 vdc fluctuating
NOJE-
The oxygen sensor heater is powered via fusedpositive (+)
battery voltage and a switchedground from the ECM. See
ELE Electrical Wiring Diagrams for specific circuit informa-
tion.
- The ground side of the oxygen sensor heater circuit is pulsed
on and off by the
DME control module.

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130-72
Fuel Injection
I Oxygen sensors, replacing
4 Four Bosch oxygen sensors (2 precatalytic converter sen-
sors and
2 post-catalytic converter sensors) provide a vary-
ing voltage signal
[0.2 vdc (max. lean) to 0.8 vdc (max. rich)]
to the ME
7.2 ECM representing oxygen content in the ex-
haust gas.
WARNING-
Exhaust manifolds and pipes can be hot enough to cause se-
rious burns. Wear suitable heavy gloves and other appropri-
ate protection.
- Using a special oxygen sensor socltet, remove the threaded
sensors from the exhaust system.
- If not already applied, coat the new oxygen sensor threads
with an anti-seize compound before installation. Do not get
compound on the sensor tip.
Tightening torque
Oxygen sensor to exhaust system
50 Nm (37 ft-lb)
Fuel injectors, removing and installing
The ME 7.2 system uses ball seat type fuel injectors. This de-
sign
prov:des precise seal'ng when the iniector is closed
therebv eiminalinq raw HC (unb~rned fue ) formalion in tne
intake.-~he fuel inkctors areswitched on and off by the ECM
at the ground side.
- Remove plastic cover from above fuel rail. See100 Engine
Removal and Installation.
- Disconnected battery negative (-) cable.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given at the front of this manual. See 001
General Warnings and Cautions.
- Remove both ignition coil covers.
Disconnect ignition coil connectors.
Remove left and right ignition coil ground wires,
4 Remove fuel injector loom boxes.
Loosen mounting fasteners
(A).
Disconnect electrical plugs (B and D).

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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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170-1 3
Radiator and Cooling ~vsteml
< V-8 engine bloclc drain plugs (one shown at arrow) are locat-
ed on each side of engine block (exhaust manifold removed
for photo).
- Place 5-gallon pail underneath engine block coolant drain
plugs.
- Remove engine bloclc coolant drain plugs and drain coolant.
- Reinstall radiator and engine block drain plugs using new
sealing washers.
- Before refilling radiator:
Switch ignition to
ON. (Do not start engine)
Set temperature controls to full warm.
- Set blower control to low.
- Using a coolant mixture of 50% antifreeze and 50% distilled
water, fill expansion tank slowly. Continue until coolant
emerges from bleed screw. Cooling system capacity is listed
in Tabled. Cooling system capacity
(V-8 models).
NOTE- Be sure radiator bleed screw is loose when filling cooling
system.
Tap water may cause corrosion of radiator, engine and
coolant hoses.
Coolant can often be reused provided it is clean and less
than two years old. Do not reuse coolant when replacing
damaged engine parts.
- Bleed cooling system. See Cooling system, bleeding
Tabled. Cooling system
capacity (V-8 models)
M62, M62 TU 12.0 liters (12.7 US qts)
Tightening torques
Block drain plug
25 Nm (18 ft-lb)
Radiator drain plug
2 - 3 Nm (18 - 27 in-lb)

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180 Exhaust System
General Exhaust System
. . . . . . . . . . . . . . . . .
Exhaust system, removing and installing
Muffler, replacing..
. . . . . . . . . . . . . . . . .
Exhaust Manifolds . . . . . . . . . . . . . . .
Exhaust manifolds, removing
and installing (M52 engine)
. . . . . . . . . .
Exhaust manifolds, removing and
installing (M52
TU and M54 engines) . . .
Exhaust manifolds, removing
and installing (M62 engine)
. . . . . . . . . .
Oxygen Sensors. . . . . . . . . . . . . . . . . . . . 180-9
Oxygen sensors (precatalyst),
replacing
(M52 TU and M54) . . . . . . . . . . . . 180-9
Oxygen sensors (post-catalyst),
replacing (M52
TU and M54) . . . . . . . . . . . . 180-9
Oxygen sensor, replacing
(M52 and M62 engine) . . . . . . . . . . . . . . . 180-10
Exhaust System Diagrams . . . . . . . . . 180-1 1
M52 engine (528i 1997-1 998) . . . . . . . . . . 180-1 1
M52
TU and M54 engines
(528i 1999-2000 and 5251 2001-2003) . . . 180-1 2
M54 engine
(530i 2001-2003) . . . . . . . . . . 180-1 3
M62 engine
(540i 1997-1 998) . . . . . . . . . . 180-1 4
M62
TU engine (540i 1999-2003 . . . . . . . 180-1 5

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... .
Exhaust System
- With exhaust system fully cold, raise and support car for ac-
cess to exhaust system.
WARNING -
Do not worlc under a lifted 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 oxygen sensor connector(s).
4 Loosen and remove bolts holding front exhaust pipes to ex-
haust manifolds (arrows). Right side of
V8 model shown.
- Support exhaust system
- Where applicable, disconnect exhaust support bracket as-
sembly from transmission.
< Remove hangers by prying off bracket (arrows).
- Lower exhaust system as a single unit to ground.
NOTE-
If the catalytic converterlfront exhaust pipe assembly is to be
replaced, transfer the oxygen sensors to the new
pipe(s).
Tightening torque
Oxygen sensor
55 Nm (41 ft-lb)
- installation is reverse of removal.
* Make sure there is at least 20 mm (314 in.) clearance be-
tween exhaust system and car body at every point.
Loosely install
ail exhaust system mounting hardware and
hangers before tightening fasteners to their final torque.
Coat manifold studs with copper paste before installing
nuts.
NOTE-
Where applicable, tighten front pipe with semi-flexible com-
pensator last when installing front pipe to
manifolds.
Tightening torques
Exhaust manifolds
to cylinder head 22 Nm (1 7 It-lb)
Front exhaust pipe to manifolds 30 Nm (22 ft-lb)
To prevent exhaust system rattles and vibration, the system
should be slightly preloaded by pushing the rear clamping
brackets forward about 7 mm (114 in).