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Fuel Injection 
Warnings and cautions 
For  personal  safety, as well  as the  protection  of sensitive 
electronic  components,  adhere to the  warnings  and cautions 
on  the  following  pages. 
WARNING- 
Gasoline is highly  flammable and its  vapors are explosive. 
Do  not  smoke  or  work  on a car  near  heaters  or  other fire 
hazards when diagnosing  and repairing  fuel system  prob- 
lems.  Have a fire  extinguisher available  in case  of an  emer- 
gency 
Renew fuel  system hoses, clamps  and O-rings any 
time they  are removed. 
When  working  on an open fuel system,  wear suitable 
hand  protection,  as prolonged contact 
with fuel  can 
cause illnesses  and skin disorders. 
* The ignition  system produces  high voltages  that can be 
fatal.  Avoid  contact  with exposed  terminals.  Use ex- 
treme caution  when 
working on a car with the ignition 
switched on  or the engine  running. 
CAUTION- 
- Disconnecting  the battery  may erase fault code($ storedin 
memory  Check  for  fault  codes prior  to disconnecting  the 
battery cables.  Read the battery disconnection cautions  in 
001 General Warnings  and Cautions. 
a Connect  and disconnect  the DME system wiring and 
1 test equipment leads  only when the ignition  is switched 
off. 
Wait  at least 1 minute  after turning  off the ignition be- 
fore  removing the  engine control module  (ECM) con- 
nector.  If the  connector  is removed  before this  time, 
residualpower  in the system  relay may damage  the 
control  module. 
Fuel  system cleaners and  other chemical additives oth- 
er  than those specifically  recommended by BMW  may 
damage the catalytic  converter, the oxygen sensor  or 
other fuel supply components. 
* Do not connect any test equipment that delivers  a 12- 
volt power supply to terminal 15 (+) of the ignition  coil. 
The  current  flow may  damage the  ECM. In general, 
connect  test equipment  only as specified  by  BMW or 
the  equipment  maker. 
Only use  a digital 
multirneter for electrical  tests. Only 
use  an LED  test light  for 
quiclc tests.    

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130-1 3 
Fuel Injection I 
< Unplug harness  connector (arrow) from sensor. 
CAUTION- 
Be sure ignition  is OFF before disconnecting  or reconnecting 
DME  system  components. 
NOTE- 
Do not  confuse  the throttle  position  sensor on  the main Nirot- 
tle body  with the throttle  position  switch on the  secondary 
throttle  body, where applicable. 
- Remove two  mounting screws holding sensor to throttle 
housing. 
- Installation  is reverse  of removal. Clear adaptation settings 
from  ECM  using BMW-compatible scan tool. 
NOTE- 
Poor idle quality  may be noticeable  for a period  if the adapta- 
tion settings  are not cleared  after installing  new TPS. 
ldle speed control  valve, 
checking and replacing 
The  idle speed  control valve regulates idle  speed by redirect- 
inq airaround  the throttlevalve.The idlespeed control valve is 
mounted  on the underside  of the intake  manifold adjacent to 
the  dipstick  tube bracket. Accessing the valve  is best  accom- 
plished  by first removing the  air filter housing  and the throttle 
body assembly. 
The  valve  issupplied  with 
batteryvoltagefrom the ECM  relay. 
The idle speed control  valve incorporates a two-coil rotary ac- 
tuator.  The ground  sides of each  coil are pulsed 
sirnulta- 
neously by  the ECM.  The duty cycle  of each circuit is varied to 
achieve  the required  idle speed. 
Afaulty  ldle speed control  valve sets afault code and the MIL 
is  illuminated  when 
OED II fault criteria  are exceeded. 
Before checking the  idle speed control valve,  confirm that the 
throttle  position  sensor is working correctly. 
- With engine  running, check that idle speed control  valve is 
buzzing. 
- Turn  on AIC system  or shift transmission into  drive. ldle 
should  remain steady  or increase  slightly.    

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130-38 
Fuel Injection 
Throttle cable, adjusting 
(MS 42.0) 
The throttle assembly  on MS 42.0 cars uses a throttle cable. 
The  cable  should be  adjusted any  time it is  disconnected or 
replaced.  This procedure  requires the factory  scan tool or an 
equivalent  to read  and adjust throttle angle.  It is  recommend- 
ed  the procedure  be done  by an  authorized 
BMW dealer ser- 
vice  department 
Basic  adjustment: 
Ensure that at  idle (accelerator  pedal in rest position) throt- 
tle  cable  has detectable play  at throttle  lever attaching 
point.  Play must not exceed  maximum allowable. 
Adjust  by  turning knurled  adjuster 
(arrow) on end  of throt- 
tle  cable  sheath  at throttle  housing. 
NOTE- 
Faulty  throttle  adjustment  values must be reset  using  the 
BMW  service tester 
DISplus, MoDiC, GTI or equivalent. 
Max. 
play at throttle  plate lever 
ldle speed control  valve, 
checking and replacing 
3 mm (0.125 in) 
The Idle speed control  valve regulates Idle speed by red~rect- 
ing air around  the throttle valve.  The ldle speed  control valve 
is  mounted 
d~rectly above  the throttle housing. Accessing  the 
valve  is best accomplished by 
flrst removing  the air fllter 
housing  and associated ducting. 
Thevalve is supplied  with batteryvoltage  from the ECM relay. 
The  idle speed control  valve incorporates a two-coil rotary ac- 
tuator.  The ground  sides of each  coil are pulsed  simulta- 
neously  by the  ECM.  The duty cycle  of each circuit  is varied  to 
achieve the  required idle speed. 
A faulty  idle speed  control valve sets a fault  code and the  MIL 
is  illuminated  when 
OED II fault criteria  are exceeded. 
Before checking the  idle speed control valve, confirm that the 
throttle position  sensor is working correctly. 
- With  engine  running, check that  idle  speed control  valve is 
buzzing. 
- Turn  on AIC system or shift transmission  into  drive. ldle 
should  remain steady or increase  slightly. 
- If idle speed  valve is not buzzing, or  if idle  decreases when 
AIC is turned  on, stop engine and disconnect harness  con- 
nector  from idle speed  valve.    

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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    

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Fuel Injection I 
4 Release spring  clips (arrows) from fuel injectors and  pull in- 
jector  electrical  loom straight  up to remove. 
4 Check that  ECM signal is present  at injector connectors. 
- Connect  digital voltmeter  to fuel injector harness plug. 
Operate  starter and 
check for voltage pulse. 
* Repeat for  each injector. 
- Remove fuel injectors by removing retaining clips 
- Installation is reverse  of removal: 
Fit new O-rings when installing injectors.  For ease  of instal- 
lation,  lightly lubricate  all fuel system O-rings with assem- 
bly lubricant. 
Check that  injector electrical connections are  correctly fit- 
ted and  that 
injectors are fully seated  prior to installing  iuel 
rail mounting bolts. 
Mass  air flow sensor  (MAF),  replacing 
The MAF sensor is provided  with operating power from  the 
ECM  relay.  Based on  calculated intake air mass,  the MAF 
generates 
avarying voltage (approx. 0.5 - 4.5 vdc)  as an  input 
signal to  the ECM. 
4 Remove  MAF sensor: 
Remove upper  air filter  housing locking clips. 
Unscrew and remove  MAF sensor harness 
(A). 
Disconnect intake air temperature sensor harness (B). 
Loosen  hose clamp (C). 
Remove upper filter  housing with sensor. 
- Installation is reverse  of removal    

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130-54 
I Fuel Injection ldle speed control  valve, 
testing  and replacing 
ldle speed  is maintained  by the ECM through  the idle speed 
control  valve. The idle control function compensates  for en- 
gine load  and engine  operating conditions.  ldle speed is 
adaptive through  the ECM and  no adjustments  can be made. 
Before checking  valve, confirm that throttle position sensor  is 
working  correctly. 
NOTE- 
The test given  below  is an  electrical check  only. It does  not 
check the  mechanical  operation of the  valve.  If the  valve  is 
sticking, hanging up or is sluggish in operation,  substituting  a 
Inown good valve is the  best  way to  check it. 
With  engine  running, check  that idle speed  control valve  is 
buzzing. 
Turn  on 
AIC or shift  car into drive.  ldle should  remain steady 
or increase  slightly. 
If  valve  is not  buzzing, or if  idle decreases  in step above,  stop 
engine  and disconnect  harness connector from  valve. 
4 Check resistance of valve across its terminals.  Test values 
are  listed  below. 
ldle  speed  control  valve coil resistance 
Terminals 
1 and 2 20 +2% 
Terminals 2 and 3 20 +2Q 
Terminals 1 and 3 40 +4% 
NOTE- 
If you  suspect  an intermittent  fault, lightly  tap the  valve  while 
testing  resistance. 
With valve harness connector disconnected, check  for bat- 
tery voltage  at redlwhite  wire in connector with  ignition on. 
If . ~~ ~~ 
there is  no voltage, check  wiring between connector and 7 ECM relay.  See ELE Electrical  Wiring Diagrams. 
NOTE- - The idle speed  control  valve receivespositive (+) battery  volt- 
age  from  the ECM  (DME  main) relay    

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Fuel Tank and Fuel Pump 
Evaporative system troubleshooting 
- Start by accessing  diagnostic trouble  codes (DTCs) using a 
BMW  or BMW compatible aftermarket scan  tool. 
For  purposes  of OBD 
II emissions compliance, the DME 
system sets a  diagnostic trouble  code (DTC) when it de- 
tects a leak that  is equal  or larger than minimum 
lealc 
sensed  by system. 
Malfunction Indicator Light (MIL) is illuminated  upon sec- 
ond recurrence  of fault.  See OBD  On-Board  Diagnostics. 
- When leak testing, observe  following conditions to obtain 
plausible results: 
Fuel  tank 
'1, to 'I., full. 
0 Vehicle  parked for at least 2 hours to  allow fuel to reach 
room  temperature. 
Ideal fuel temperature is  10"- 20°C 
(50" 
- 68" F). 
Do not  refuel immediately before 
lealc test. 
- If a leak  is detected, check the  following areas: 
* Fuel filter cap (leaking  or off). 
Fuel  tank ventilation lines leaking at fuel 
tank or activated 
carbon  canister. 
i 
Tank ventilation  valve leaking (in engine compartment). 
Fuel  level 
sensorlfuel pump cap  leaking. 
Evaporative system component replacement  is covered later 
in 
th~s group in Fuel Tank and  Fuel Lines.    

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- Raise and safely  support  vehicle 
WARNING- 
Make sure the car  is stable  and well supporied at all times. 
Use a professional  automotive /iff orjack stands designed for 
the 
ournose. A floor jack is  not  adeouate suooort. 
- If necessary, remove transmission  splash shield. 
- Disconnect fluid  line from slave cylinder  on lefl  side  of trans- 
mission.  Place  pan under hose to catch dripping fluid. 
4 Working underneath transmission,  remove slave cylinder 
mounting  nuts (arrow)  from clutch  housing and remove 
cylinder. 
- Installation is reverse  of removal, noting the following: 
Check  for wear  on slave cylinder.  Any wear except  on tip is 
caused  by misalignment  of clutch  components. 
Lightly coat 
pushrod tip with molybdenum disulfide grease 
(MolyltoteIB Longterm or equivalent). 
. During  installation  be sure pushrod tip engages  recess in 
clutch  release  lever. 
Fill fluid  reservoir with clean fluid. 
. Bleed clutch  hydraulics as  described earlier. 
Tightening 
toraues - -. 
Clutch  slave cylinder to  transmission 22 Nm (16 R-lb) 
Fluid line to slave  cylinder 17 Nm (13 ft-lb) 
The  transmission must  be removed from  the engine to access 
the  clutch mechanical components.  It is recommended that 
the  clutch  disc, pressure plate  and release bearing  be re- 
placed  during a  clutch overhaul. 
Besure tocheck the bottom  of the  bellhousing foroil. If engine 
oil is found, check for a faulty rear crankshaft main oil seal. 
See 
119 Lubrication  for rear main seal replacement. 
Clutch variations 
Two versions  of the  clutch  are used: 
1997  528i (6 cylinder)  uses traditional  clutch components. 
All 
540i (V-8)  and 1998  and later 6 cylinder models from 
use a self-adjusting  clutch (SAC).