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120-1 6
Ignition System
Remove camshaft sensor (arrow) from front of right cylinder
head.
Disconnect camshaft sensor harness from cable duct above
right cylinder head.
Installation is reverse of removal, noting the following:
Use new O-ring when installing sensor.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear ECM fault memory.
Tightening torque Intake camshaft sensor to timing chain 5 Nm
(3.5 ft-lb)
cover
Knock sensors
Knock sensors, replacing (M52, M52 TU and M54
engines)
The knock sensors are bolted to the left side of the cylinder
block under the intake manifold.
- Remove intalte manifold as described in 113 Cylinder Head
Removal and Installation.
D~sconnect knock sensor electrical harness connector (A) on
left side of engine cylinder block.
Remove knock sensor
mount~ng bolts (arrows) on side of
cyllnder block. Remove sensors.
Note the installed angle of the
lnocl~ sensor on the bloc/( be-
fore removing it. Reinstall the sensor
in the same position. Be
sure to use a torque wrench when tightening the sensor
mounting bolt.
< Clean lknock sensor contact surface on engine bloclc and
sensor (arrows) before installing
ltnock sensor.
Tightening torque
Knock sensor to head 20 Nm (15 ft-lb)
- Use scan tool to read out and clear ECM fault memory.
Knock sensors, replacing
(M62 and M62 TU engines)
The
knock sensors are bolted to the side of the cylinder block
under the
intake manifold.
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Ignition System
Remove intake manifold as described in 113 Cylinder Head
Remaval and Installation.
Remove knock sensor mounting bolts (arrows) on side of
cylinder block. Remove sensors.
I CAUTION- I
Note the installedangle of the knock sensors on the bloclt be-
fore removalit. Reinstall the sensors in the same position. Be
sure to use
a torque wrench when tightening the sensor
mounting bolts.
Clean
lknoclc sensor contact surfaces on engine bloclc and
sensors before installing.
Tightening torque
Knock sensor to engine
bloclc 20 Nm (15 ft-lb)
- Use scan tool to read out and clear ECM fault memory.
- Installation is reverse of removal.
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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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I Fuel Injection
Release injector locking clips at each injector and pry injector
wiring duct up off injectors.
Clamp off fuel supply line and fuel return line at end of fuel
rail. Disconnect fuel supply fuel return lines from fuel rail.
WARNING -
Clamp off the fuel lines and then wrap a clean shop towel
around the lines before removing them. Residual
fuelpres-
sure is present in the lines.
Fuel is discharged. Do not disconnect any wires that
could cause electrical
sparks. Do not smoke or work
near heaters or other fire hazards. Keep an approved
I fire extinguisher handy. I
- Remove fuel rail mounting fasteners
- Pull up on fuel rail and remove individual injectors by remov-
ing injector retaining clip and pulling injector from rail.
- Installation is reverse of removal. Fit new O-rings when in-
stalling injectors. For ease of installation, lightly lubricate in-
jector O-ring with
SAE9O gear lube.
Tightening torque Fuel rail to
intake manifold 10 Nm (89 in-lb)
Evaporative emissions, overview
On E39 MS 41 .I cars, the evaporative emissions system is
combined with the tank ventilation system. The evaporative
system is monitored by the ECM for correct purge operation
and leak detection.
The carbon (purge) canister is purged using engine vacuum
via the
purgevalve.The purgevalve (located nextto the mass
airflow sensor) is ECM controlled and regulates the purge
flow into the intake manifold. The valve is powered open and
closed by an internal spring.
If the evaporative emission valve circuit is faulty, a fault code
is set and the MIL is illuminated when OBD
II fault criteria are
exceeded. If the valve is mechanically faulty, poor driveability
may result and a mixture adaptation fault is stored in the
ECM.
The leak diagnosis pump (LDP) is activated by the ECM and
pressurizes the fuel tank and evaporative system as apart of
theOED I1 leakdetection monitor. If the LDP orthe LDP circuit
is defective, afault code is set and the MIL is illuminated when
OBD
I1 fault criteria are exceeded. The LDP is mounted the
left rear wheel well behind the fender liner.
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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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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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-- -
Exhaust System
Oxygen sensors (precatalyst), replacing
(M52 TU and M54)
The precatalyst oxygen sensors are installed at the top of the
exhaust manifolds.
WARNING-
Allow components to cool before servicing.
- Using BMW scan tool DlSplus (Diagnostic Information Sys-
tem) or equivalent, read out and clear ECM fault codes.
Working at right side of engine above exhaust manifolds,
remove front or rear oxygen sensor harness connector
(arrows) from bracket, then separate plug.
NOTE-
In photo, secondary air pump has been removed for clarity.
Remove oxygen sensor using special oxygen sensor
removal socket.
Installation is reverse of removal
New sensor threads come coated with anti-seize paste.
If reusing a sensor, apply thin coat of anti-seize paste to
threads only. Do not contaminate tip of sensor with paste
or lubricants of any sort.
Install harness and connector in original location.
Tightening torque
- -.
Oxygen sensor to manifold 50 Nm (37 ft-lb)
Oxygen sensors (post-catalyst), replacing
(M52 TU and M54)
The post-catalyst oxygen sensors are installed at the rear of
the catalytic converters.
WARNING-
Allow components to cool before servicing
- Using BMW scan tool DlSplus or equivalent, read out and
clear ECM fault codes.
- Remove large cover from above fuel raillintake manifold.