LR3/Disco 3
The ECM controls six fuel injectors located on the cylinder head. The injectors are fed from a common fuel rail as part of a
‘return less’ fuel system.
Fuel rail pressure is constant at 4.5 bar (59 psi) and is regulated by a regulator that is integral to the fuel pump module.
The ECM monitors the output power stages of the injector drivers for electrical faults. The injector has a default resistance
of 14.5 Ohms at 20 Degrees Celsius. For additional information, refer to
Fuel Charging and Controls
(303-04A Fuel
Charging and Controls - 4.0L)
SPARK PLUGS
It is essential that only factory-approved spark plugs be used in service. DO NOT attempt to use ‘equivalent’ spark plugs.
Use of unapproved spark plugs may cause the misfire detection system to malfunction, and the ECM to store misfire
faults.
IGNITION COILS
The Land Rover V6 engine is fitted with ignition coils that are driven directly by the ECM. The coils are mounted on top of
the inlet manifold and are connected to the spark plugs by High Tension (HT) leads. The positive supply to the coil is fed
from fuse 19 in the Battery Junction Box (BJB). Each coil contains a power stage to trigger the primary current. The ECM
sends a signal to each of the coils power stage to trigger the power stage switching. Each bank has a feedback signal
that is connected to each power stage. If the coil power stage fails the feedback signal is not sent, causing the ECM to
store a fault code.
FUEL PUMP RELAY
The V6 engine has a return less fuel system. The system pressure is maintained at a constant 4.5 bar , with no reference
to intake manifold pressure. The fuel is supplied to the injectors from a fuel pump located within the fuel tank. The
electrical supply to this fuel pump is controlled by the ECM via the fuel pump relay, in the event of a vehicle impact the
ECM will receive a crash signal from the restraints control module and will cut the power supply to the fuel pump relay.
The fuel system is pressurised as soon as the ECM is powered up, the pump is then switched off until engine start has
been achieved.
The fuel pump relay is located in the Central Junction Box (CJB). The Fuel pump is contained within the fuel tank. For
additional information, refer to
Fuel Tank and Lines
(310-01A Fuel Tank and Lines - 4.0L)
