(M50 And M60 Engines); Engine; Replacing - BMW 1989-1995 525i Service Manual

FUEL INJECTION-DME
130-1
130 Fuel Injection-DME
GENERAL
130-1
Principle of Operation . . . . . . . . . . . . . . . . . . . . 130-2
Basic Engine Settings . . . . . . . . . . . . . . . . . . . 130-2
Fault Diagnosis 130-3
Warnings and Cautions . . . . . . . . . . . . . . . . . . 130-3
FUEL PRESSURE TESTS
130-3
Relieving Fuel Pressure and Connecting
Pressure Gauge . . . . . . . . . . . . . . . . . . . . . . 130-4
System pressure, checking 130-4
Residual pressure , checking 130-5
Fuel pressure regulator response
to engine load , checking ..... . . • , , , . . . . 130-5
ELECTRICAL CHECKS AND COMPONENT
TESTING
130 -5
Main relay , testing 130-5
Engine coo lant temperature (ECT)
sensor, testing . . . . . . . . . . . . . . . . . . . . . . . 130-7
Intake air temperature sensor, testing
(M50 and M60 engines) 130-7
Throttle position switch, checking
(M20 and M30 engines) 130-8
Throttle position sensor, checking
(M50 and M60 engines) 130-8
Air Flow Sensor 130-9
Air flow sensor, checking
(M20 and M30 eng ines) 130-9
Air flow sensor, checking
(M50 eng ine ) 130-9
Air flow sensor, checking
(M50TU and M60 eng ines) 130-10
Fuel injectors, checking 130-11
Oxygen sensor, checking . . . . . . . . . . . . . . . 130-11
Idle speed control valve, checking 130-12
COMPONENT REPLACEMENT
130-13
Engine control module (ECM), replacing 130-13
GENERAL
This repair group covers fuel injection component testing
and repair . Special equipment may be necessary for some of
the procedures given in this repair group. If you do not have
the equipment required to do the job. it is recommended that
these repairs be left to an authorized BMW dealer. The BMW
dealer is equipped with sophisticated diagnostic test equip -
ment that is capable of quickly pinpointing hard-Io-find DME
fuel injection problems.
Engine coolant temperature
(ECT) sensor . replacing , 130-14
Throttle position switch or
sensor, replacing 130-14
Fuel injectors, replacing 130-14
Fuel rail and injectors,
removing (M20 engine) 130-14
Fuel rail and injectors,
removing (M30 engine) 130-15
Fuel rail and injectors,
removing (M50 engine) 130-1 6
Fuel rail and injectors .
removing (M60 engine) 130-16
Fuel pressure regulator, replacing . . . . . . . . . 130-17
Idle speed control valve,
replacing (M20 and M30 engines) 130-18
Idle speed control valve,
replacing (M50 engines) 130-18
Idle speed control valve,
replacing (M60 engines) 130-19
Air flow sensor , replacing (M20 engine) 130-19
Air flow sensor, replacing (M30 engine) 130-19
Air flow sensor , replacing (M50 engines) 130-19
Air flow sensor, replacing (M60 engines) 130-19
ECM PIN ASSIGNMENTS
130-20
TABLES
a. DME System Variants 130-2
b. Fuel Pressure Specifications 130-4
c. Engine Coo lant or Intake Air Temperature
Sensor Test Values 130-7
d. Throttle Position Sensor (M50/M60 engines) . 130-8
e. ECM Pin Ass ignment-DME 1.3 130-21
f. ECM Pin Assignment-DME 3.1 130-23
g. ECM Pin Assignment-DME 3.3 130-25
h. ECM Pin Assignment-DME 3.3 .1 130-27
NOTE -
• Complete wiring diagrams for the DME engine men-
agement system. including the EML (electronic tnrot-
tle control) circuit. can be found at the rear of the
manual under Electrical Wiring Diagrams.
• For DME ignition repair information. including testing
the crankshaft position/rpm sensor and the knock
sensors. see 120 Ignition System-DME.
• For fuel supply component testing and repair. see 160
Fuel Tank and Fuel Pump.
GENERAL