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Fuel Injection
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Remove engine coolant temperature sensor:
Unclip crankcase vent hose
(C) from cylinder head cover.
Remove plastic cover
(6) from atop intake manifold run-
ners.
Working under front of intake manifold, disconnect ECT
harness.
Unscrew ECT sensor
(C) from cylinder head.
Installation is reverse of removal:
Use new copper sealing washers when installing sensor.
Replace any engine coolant lost.
Tightening torque
Temperature sensor to cylinder head
13 Nm (10 it-lb)
Intake air temperature ([AT) sensor,
testing and replacing
4 The intake air temperature (IAT) sensor (arrow) signal is
used by the ECM to monitor intake air temperature for fuel
and
igntion adaptation. The sensor is .ocared in rne 'ntane
man:lold behind the throttle housng.
The ECM monitors an applied voltage (5 vdc) to the sensor
The voltage drop across the sensor varies as the intake air
temperature (sensor resistance) changes.
NOJE-
The IATsensor is an NTC (negative temperature coefficient)
type sensor. In other words, as the temperature rises, resis-
tance through the sensor decreases.
If the IAT sensor input is implausible, a
fault code is set.The
MIL is illuminated when OED II fault criteria are exceeded.
The ECM then operates the engine using only the engine
coolant temperature (ECT) sensor input.
The intake air temperature sensor can be tested using a
mul-
timeter across its terminals:
/ IAT sensor resistance @ 20" C (68°F) / 2.2 - 2.7 lkCk
~ -- ~~ -
CAUTION--
Be sure ignition is
OFFbefore disconnecting or reconnecting
DME system components.
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Fuel Injection
Engine coolant temperature
(ECT) sensor,
testing and replacing
4 The ECT sensor is located below cylinder 6 intake port at the
rear of the engine (1).
The ECT sensor is a dual temperature sensor. One circuit
provides coolant temperature information to the ECM while
the other circuit provides coolant temperature information to
the instrument cluster.
The ECM determines the correct ignition timing and airlfuel
mixture required
forthe engine temperature by monitoring an
appliedvoltage
(5vdc) to the sensor.Thevoltage drop across
the sensor varies as the coolant temperature (sensor resis-
tance) changes.
NOTE-
The ECT sensor is an NTC (negative temperature coeffi-
cient) type sensor. In other words, as the temperature rises,
resistance through the sensor decreases.
If the ETC sensor input is faulty or non-plausible, the MIL is il-
luminated when the MIL is illuminated when
OED II fault crite-
ria are exceeded. The ECM assumes a substitute value
(80" C 11 76'F) to maintain engine operation. The ignition tim-
ing is set to a
conservativelsafe basic setting.
- Remove intake manifold to access ECT sensor on the M52
TU and the M54 engines. See 113 Cylinder Head Removal
and Installation.
- Check ECT sensor resistance using a multimeter at sensor
terminals.
WARNING -
Due to rislc of personal injury, be sure the engine is cold be-
fore removing ECT sensor connector.
ECT sensor resistance @ 20°C (68°F)
CAUTIOI\C
Be sure ignition is OFFbefore disconnecting or reconnecting
DME svstem components.
2.2 - 2.7 k
4 Disconnect ECT sensor harness connector (arrow). Un-
screw ECT sensor from cylinder head.
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Fuel Injection
- Installation is reverse of removal:
Use new copper sealing washers when installing sensor.
Replace any lost coolant.
Tightening torque
Temperature sensor to cylinder head
13 Nm (10 ft-lb)
Intake air temperature (IAT) sensor,
testing and replacing
4 The intake airtemperature (IAT) sensor, located at the top of
I the intake manifold, adapts (fine tunes) the fuel mixture and i
T engine timing based on varying intake air temperatures.
i If the intaite air temperature signal is implausible, a fault code
! is set and the MIL is illuminated when OBD I1 fault criteria are
I exceeded. The ECM then operates the engine using the ECT
i sensor sional inout as a back uo.
type sensor. In other words,
a> the temperature rises, resis-
tance through the sensor decreases.
lid I The IATsensor can be tested using a multimeter:
/IAT sensor resistance at 20'C (68°F) 2.2 - 2.7 kd
Remove engine cover by prying off plastic trim caps (arrows)
and removing nuts below caps.
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Radiator and Cooling systeml
Tightening torques
Block drain plug to block 25 Nm
(18
it-lb)
Coolant hose clamp (32 - 48 2.
5 Nm (22 in-lb)
mm hose diameter)
Radiator drain plug to radiator
2-3Nm(l8-27in-lb)
Thermostat housing to cylinder
head 10 Nm (89 in-lb)
I Coolant thermostat housing assmbly- - I
Thermostat, removing and installing
(M52 TU or M54 engine)
4 The electric map-controlled thermostat is part of the thermo-
stat housing at the front of the cylinder head.
1. Bolts (M6)
2 Bolt (ME)
3. Housing with thermostat
4. Gasket
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate
ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling (6-cylinder models).
CAUTION-
Allow cooling system to cool before opening or draining the
system.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Disconnect electrical harness connector from thermostat
housina.
4 Lever out retaining clips (arrows) and pull hose fittings off
thermostat housing.
- Unbolt and remove thermostat housing from front of engine.
Loosen nut at top of engine lifting eye to facilitate removal.
- Installation is reverse of removal, noting the following:
Keep sealing faces free of oil.
* Use new sealing gasket.
When reinstalling hose to thermostat housing, install clip
on hose end fitting, then push hose onto housing until it
clicks into place.
Fill system with coolant. See Coolant, draining and fill-
ing (6-cylinder models).
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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).
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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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1 Exhaust ~vsteml
NOTE-
The front exhaust manifold must be removed before the rear
manifold.
- Installation is reverse of removal.
Coat exhaust mounting studs with CRC or equivalent cop-
per paste.
Use new gasltets and self-locking nuts.
Tightening torques Exhaust manifold to cylinder head 20 Nm
(15 ft-lb)
Front exhaust pipe to manifold 30 Nm
(22 ft-lb)
Oxygen sensor to manifold 50
Nrn (37 ft-lb)
Exhaust manifolds, removing and installing
(M62 engine)
Always use new retaining nuts and gasltets when removing
and installing the exhaust manifolds.
NOTE-
Access to manifolds is extremely limited. If removing exhaust
manifolds as part of additional engine worlc (such as cylinder
head removal), it may be easier to first remove engine.
- With exhaust system cold, raise and support car for access
to exhaust system.
WARNING -
Do not work undera lifted car unless it is solidly supported on
jaclt stands designed for the purpose. Never worlc undera car
that is supportedsolely
by a jack.
- Remove exhaust system. See Exhaust system, removing
and installing.
- Removing right side exhaust manifolds (cylinder bank 1-4):
Remove heat baffle plate.
Disconnect plug connection to oxygen sensor.
securing exhaust manifolds to head.
Remove manifolds towards bottom.
- Installation is the reverse of removal.
Coat exhaust mounting studs with CRC or equivalent
copper paste.
Use new gasltets and self-loclting nuts.
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- Removing left side exhaust manifolds (cylinder bank 5-8):
- Remove heat baffle plate on left side.
Remove oxygen sensor using
BMW special tool 11 7 030
or similar oxygen sensor socket.
Install
BMW special tools 00 0 200,OO 0 201,OO 0 202,OO 0
204, and 00 0 208 or other suitable engine lifting support
above engine and attach to lifting eye on left head.
NOTE-
The supports on special tool 00 0 208 must rest on the
screws on the fenders.
- Remove nut at top of engine support on left side
- Raise engine at front suspension lug a maximum of 25 mm
(I
.O in).
Release clamping bolt and nut
(arrow) and slide universal
joint off steering gear.
4 Remove nuts securing left exhaust manifold to head,
Raise front of manifold as high as possible past end posi-
tion of steering gear and feed out towards bottom.
- Installation is reverse of removal.
Coat exhaust mounting studs with CRC or equivalent
copper paste.
Use new exhaust gaskets and self-locking nuts.
Install new self-locking nuts on engine mount and steering
shaft bolt.