2001 BMW 525i Throttle

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. - --
j Cylinder Head Removal and Installation
4 Working at throttle housing, unscrew and disconnect electri-
cal harness plug
(arrow).
4 Disconnect electrical harness connector at fuel tank venting
valve
(A) and vent hose at quick disconnect fitting (arrow).
- Working under intake manifold, disconnect the following:
Engine oil dipstick tube support.
Oil separator return line from dipstick tube.
Knock sensor harness connector from support.
4 Working underneath car, remove intake manifold support
mounting nut
(arrow), located adjacent to left engine mount.

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Cylinder Head Removal and Installation
- Install exhaust manifolds using new gaskets and nuts. Coat
manifold studs with copper paste prior to installing nuts.
Tightening torque Exhaust
maniiold to cylinder head (M7)
20 Nm (15 ft-lb)
- Install electrical harness connectors for oil pressure sender
and coolant temperature sensor before installing
intalte man-
ifold.
7 Install intake manifold:
1. Manifold mounting nuts: tighten to 15 Nm (1 1 ft-lb)
2. Fuel pipe bracltet
3. Fuel pipe bracltet
4. Vacuum pump bracltet
5. Manifold mounting bracltet
6.
Tank venting valve bracltet
7. Mounting bracket to manifold bolt (M6)
8. Mounting bracket to cylinder block nut (MIO), tighten to
47 Nm (33 fi-lb)
Intake manifold installation is reverse of removal, noting the
following:
* Use new fuel injector seals.
Carefully
check intake manifold gasket and replace if nec-
essary.
Inspect O-ring seal between mass air flow sensor and air
filter housing. To facilitate reassembly, coat seal with
acid-
free grease.
Use new fuel injector seals.
Carefully check intake manifold gasket and replace if
necessary.
CA UTIOPI-
When reattaching throttle assembly harness connector, con-
nector is fully tightened when arrows on connector
andplug
line up.
Tightening torque
lntalte manifold to cylinder
head (M7)
15 Nm (1 1 it-lb) ~ ~- Mounting bracket to cylinder bloclt (M10) 47 Nm (33 ft-lb)
Mounting bracket to intake manifold (MI?) 10 Nm (89 in-lb)

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Cylinder Head Removal and Installation
Pry out ignition coil cover trim caps,
covers from lefl and right sides. remove fasteners
and
< Disconnect throttle cables from throttle shafl (A) and remove
cables from support bracket
(B).
< Disconnect cable from jump start post (arrow) on left cylinder
head cover.

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- .-
.. Cylinder Head Removal and Installation I -
< Disconnect the following electrical harness connectors:
Knock sensors
(A).
Thermostat (6).
Throttle position sensor and idle valve (C).
Camshaft position sensor (D).
Ignition coils (E).
< Remove mounting nuts (arrows) from wiring harness ducts.
4 Release fuel injector connectors by releasing spring clip
(arrow) on each injector.
Lift up and remove electrical ducts and set to one side

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-. .
Cylinder Head and Valvetrain -- v . -- --- --
4 Remove air filter housing and ducts:
Loosen hose clamps as necessary and disconnect electri-
cal harnesses.
- Remove air filter housing mounting fastener (arrow).
Loosen hose clamp at throttle body.
Remove air filter housing with mass air flow sensor and
duct.
Disconnect the following electrical harness connectors.
Knoclc sensors (A).
Thermostat housing (B).
Throttle position sensor/throttle position switch and idle
valve
(C).
Camshaft position sensor (D).
* Ignition coils (E).
Remove mounting nuts (arrows)
ducting. from
wiring harness

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1 17-34
1 Camshaft Timing Chain
DOUBLE VAMOS SYSTEM
(M52 TU AND M54 ENGINES)
Double VANOS system function
The M52TU and M54 6-cylinder engines are equipped with a
Double VANOS system that varies intake and exhaust cam-
shaft timing.
The main components of the Double VANOS system are:
lntalte and exhaust camshafts with helical spline inserts.
Camshaft sprockets with adjustable gears.
VANOS actuators (two position piston housing with
inter-
nallexternal helical spline cup).
Three-way solenoid switching valves.
Camshaft position impulse wheels.
Hall effect camshaft position sensors.
Camshaft position
IS varied based on engine rpm, throttle po-
sition signal, intake air and coolant temperature.

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Camshaft Timing chain1
- Disconnect negative cable (-) from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given
in 001 General Cautions and
Warnings.
4 Removing top and side engine covers:
Press down on locking pins (arrows) to release locks. Lifl
intake manifold cover straight up to remove.
Pry out caps from side covers.
Remove fasteners
and covers.
NOTE-
Some early models use
pry out trim caps and fasteners to
hold the top cover in place.
Disconnect electrical harness connectors at ignition coils
(A).
Remove left and right side ignition coil mounting fasteners
and coils.
NOTE-
Make note of location of ground strap (arrow).
Remove spark plugs.
- Remove posltlve (+) terminal cable from left cylrnder head
cover.
- Unbolt left and right side cable ducts from fuel rail
Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and intake air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow)
Loosen intake hose clamp
(C).
Remove air filter housing with mass air sensor and intake
duct from throttle body assembly.

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Camshaft Timing chain1
< Remove Automatic Stability Control (ASC) throttle body:
Disconnect electrical harness from throttle position sensor.
Disconnect ASC actuator cable (arrow).
Remove
3 mounting fasteners and remove throttle body.
4 Disconnect fuel tank vent valve line and cap off line (arrow).
- Drain engine coolant and remove hoses from thermostat
housing. See
170 Radiator and Cooling System.
- Remove water pump and thermostat housing. See 170 Ra-
diator and Cooling System.
- Remove left side upper timing chain cover retaining bolts and
remove cover.
4 Counter hold right intake camshaft
CAUTION-
Counter hold camshaft with a 27mm open-end wrench while
loosening sprocket bolts. Grind wrench if necessary to pre-
vent damage to head.