Oxygen Sensors. Replacing; Fuel Injectors. Removing And Installing - BMW 5251 Service Manual

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).