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.. .-
/Fuel lnjeciion
NOJE-
With engine oft disconnect harness connector and checlc
heating element resistance between white wires on the sen-
sor side of harness. If the element is electrically open (no
continuity), replace sensor.
- If oxygen sensor does not produce a fluctuating voltage and
preheater circuit is
OK, replace sensor.
NOJE-
If not already applied, coat oxygen sensor threads w~th anti-
seize compound before installat~on. Do not get the com-
pound on the sensor tip.
Tightening torque Oxygen sensor to exhaust system
55 Nm (41 ft-lb)
Fuel injectors, checking and replacing
The fuel iniectors are switched on and off (oaened and
closed)
by'the ECM. The injectors are connkcted to acom-
mon power source. A ground signal from the ECM is used to
open and close the injectors.
CA U JIOG
Use only a digital multimeter or an LED injector tester when
testing injectors or wiring. Use of an analog
VOM or incan-
descent test light may damaqe the engine controlmodule.
4 Remove fuel rail cover. See 110 Engine Removal and in-
stallation.
With the engine running, place the point of a long screwdriver
on each injector and check for a cliclting vibration.
If no vibra-
tion is found do the voltage
checit shown below.
Injector electrical loom removal:
- Loosen mounting nuts A.
Remove ground wire C.
Disconnect ignition coil harness D
Page 516 of 1002

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.," --
Radiator and Cooling System --- 1
insert two M6 screws (arrows) in tapped bores and tighten
uniformly until pump is free from timing chain cover (thermo-
stat and hoses have been removed for purposes of visual
clarity).
Installation is reverse of removal, noting the following:
Be sure to replace sealing O-ring and gaskets.
Coat O-ring with water-based lubricant during installation.
Refill with coolant. See Coolant, draining and filling
(6-
cylinder models).
Tightening torques
-
Coolant pump to timing chain 10 Nm (89 in-lb)
cover
Coolant pump pulley to coolant
10 Nm (89 in-lb
pump
Engine block drain plug to block 25 Nm (1 8 It-lb)
Radiator drain plug to radiator 2 - 3 Nm (I8 - 27 in-lb)
Coolant pump, replacing (V-8 models)
I 1 < The engine coolant pump is mounted in the front of the en-
gine in ;he timing chain cover.
1. Thermostat housing
2. Thermostat
3. Thermostat sealing O-ring
4. Water pump
5. Water pump gasket
- Drain cooling system. See Coolant, draining and filling (V-
8 models).
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Remove engine drive belts: See 020 Maintenance.
NOTE-
Mark direction of drive belt rotation if reusing belt,
- Remove vibration dampener. See 117 Camshaft and Tim-
ing Chain.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with
MAF sensor.
- Disconnect coolant hoses from thermostat housing and cool-
ant pump housing.
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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).
Page 533 of 1002
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Exhaust System
M52 engine
(5281 1997-1 998)
1. Exhaust manifolds
2. Sealing washer
3. Plug
4. Gasket (manifold to cylinder
head)
5. Clamping sleeve
6. Post-catalytic converter oxygen sensor
7. Pre-catalytic converter oxygen
sensor
8. Hanger
9. Rear muffler
10. Vibration dampener
11. Center support bracket
12. Clamping sleeve
13. Front pipe with catalytic
converters
14. Hanger
15. Center muffler
16. Gasket (front pipe to manifold)
Page 534 of 1002
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I Exhaust System
M52 TU and M54 engines
(528i 1999-2000
and 525i 2001-2003)
1. Transmission bracket
2. Center support bracket
3. Front muffler
4. Clamping sleeve
5. Vibration dampener
6. Hanger
7. Rear muffler
8. Hanger
9. Center muffler
10. Oxygen sensors, post-catalytic
converter
11. Oxygen sensors, pre-catalytic
converter
12. Exhaust manifoldlcatalytic
converter assemblies
Page 535 of 1002
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Exhaust systeml
M54 engine
(5301 2001-2003)
Clamping sleeve
Front muffler Rear muffler
Hanger
Vibration dampener
Clamping sleeve
Center muffler
Hanger
Gasket (front pipe to manifold)
10. Exhaust
manifold/catalytic
converter assemblies
11. Oxygen sensors, post-catalytic converter
12. Oxygen sensors, pre-catalytic converter
Page 609 of 1002

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Driveshaft
4 Driveshaft center slide nut spanner
(Tool No. BMW
26 1 040)
7, 25 1 Ho 4 cv joint removal tool
(Tool No. BMW 26 1 11 0)
support assembly
Driveshaft description
4 The two-piece driveshaft is connected to the transmission by
a rubber flex-disc and to the rear final drive by a constant ve-
locity (CV) joint.
A universal joint is used at the center of the driveshaft and
the shaft is supported in the middle by a center support
bearing. The bearing is mounted in rubber to isolate vibra-
tion.
- The rear constant velocity joint compensates for fore and
aft movement of the drive line.
Troubleshooting
The source of driveline vibrations and noise can be difficultto pin-
point. Engine, transmission, rear axle, or wheel vibrations can be
transmitted through thedriveshaftto the car body. Noises from
thecar may be caused by final drive problems, or by faulty wheel
bearings, drive axles, or even
wom or improperly inflated tires.
NOTE-
For drive axle repair information, see 331 Final Drive
Driveshaft noise or vibration may be caused by worn
ordam-
aged components. Check the universal joint for play. With the
driveshaft installed, pull and twist the driveshaft while watch-
ing the joint. The
BMW specification for play is very small, so
almost any noticeable play could indicate a problem.
Check the torque of the fasteners at the flange connections.
Check the rubber of the flex-disc and center bearing for dete-
rioration or tearing. Check the driveshaft for broken or miss-
ing balance weights. The weights are welded tabs on the
driveshaft tubes. In addition to inspecting for faulty driveshaft
parts, the installed angles of the driveshaft should also be
considered.
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1 Driveshaft
Further inspection requires removal of the driveshaft. Checlc
the front centering guide on the transmission output flange for
damage or
misalignment. Also check runout at the transmis-
sion output fiange and output shaft, and at the final drive input
fiange. Check the bolt hole bores in the flange for wear and
elongation.
Driveshaft flange
runout (max. allowable)
Transmission
flange
- Axial play 0.10 mm (0.004 in.)
Radial play 0.07
mm (0.003 in.)
Spin the driveshaft center bearing and
check ior smooth op-
eration without play. Check the constant velocity joint
forwear
or play. Checlc the universal joint for wear or binding. If it is
difficult to move or binds, the driveshaft section should be
replaced.
Universal joint
play
Maximum allowable 0.15
mm (0.006 in.)
NOTE-
With the driveshaft installed, the actual amount that the drive-
shaftjoint pivots is limited. For the most accurate test, check
joint
in its normal range of movement.
If inspection reveals nothing wrong with the driveshaft, it may
need to be rebalanced. This can be done by a speciality drive-
shaft repair shop. Also,
checlc driveshaft alignment as de-
scribed below.
NOTE-
Minor driveshaft vibrations can often be corrected simply by
disconnecting the driveshaft at the final drive and reposition-
ing it go", 180" or 270" in relation to the final drive input
flange.
The troubleshooting table below lists symptoms
oi driveshaft
problems and their probable causes. Most of the repair infor-
mation is contained within this repair group. There are refer-
ences to other repair groups, where applicable.