Land Rover Defender V8i Electrical Library Rover Manual

DESCRIPTION AND OPERATION
4.10
DEFENDER V8i
IGNITION SYSTEM
The ignition system utilises a direct ignition system (DIS) negating the need for
a distributor. The system comprises 4 double ended coils operating the wasted
spark principle. The circuit to each coil is controlled by the ECM. When a coil
fires, a spark is produced in two cylinders, however, as the resistance is higher
in the cylinder on the compression stroke, more spark energy is dissipated in
this cylinder.
The ECM determines the optimum...

DESCRIPTION AND OPERATION
DEFENDER V8i4.11
Camshaft position (CMP) sensor
The CMP sensor is used in conjunction with the CKP sensor to inform the ECM
of the position of the engine in the 4 stroke cycle. Using the CKP sensor alone,
the ECM is unable to determine whether a cylinder is on its compression stroke
or exhaust stroke.
The sensor uses the principle of magnetic induction to generate the signal. The
cam wheel has four gaps, one smaller than the others, which pass in close
proximity to the CMP...

DESCRIPTION AND OPERATION
4.12
DEFENDER V8i
Using the signal from the knock sensor in conjunction with the CKP and CMP
signals enables the ECM to identify which cylinder is producing the knock and
hence retard the ignition timing of that cylinder only. The ignition timing of the
cylinder producing the knock is retarded until the knock disappears. The ECM
then advances the ignition timing to find the optimum advance angle for that
cylinder. The ECM is able to perform a similar function for each of the 8...

DESCRIPTION AND OPERATION
DEFENDER V8i4.13
Camshaft position (CMP) sensor
The CMP sensor is used in conjunction with the CKP sensor to inform the ECM
of the position of the engine in the 4 stroke cycle. Using the CKP sensor alone,
the ECM is unable to determine whether a cylinder is on its compression or
exhaust stroke.
The sensor uses the principle of magnetic induction to generate the signal. The
cam wheel has four lobes which pass in close proximity to the CMP sensor as
the camshaft rotates. The lobes...

DESCRIPTION AND OPERATION
4.14
DEFENDER V8i
Throttle position (TP) sensor
The TP sensor measures the angle of throttle opening and the rate of change
of throttle position. The angle of throttle opening gives an indication of the
quantity of air being drawn into the engine. The rate of change of throttle angle
gives an indication of rate of acceleration demanded.
The sensor is a rotary variable resistor mounted to the throttle butterfly spindle
giving an output of 0 to 5 volts.
Engine coolant temperature...

DESCRIPTION AND OPERATION
DEFENDER V8i4.15
Heated oxygen sensor (HO2S)
2 HO2Ss are fitted to the vehicle, 1 before each catalyst. A HO2S comprises a
titanium metal sensor surrounded by a gas permeable ceramic coating.
Oxygen permeating the ceramic coating reacts with the titanium wire, altering
its resistance. The resistance of the sensor is directly related to the quantity of
oxygen around the sensor. The HO2S does not function correctly until it
reaches a temperature of approximately 300°C and so a...

DESCRIPTION AND OPERATION
4.16
DEFENDER V8i
Fuel pressure regulator
The fuel pressure regulator is a mechanical device mounted to the fuel rail. Its
purpose is to control the fuel rail pressure with respect to the inlet manifold
depression. The fuel rail pressure must be reduced at high manifold
depressions to avoid excess fuel being drawn through the injector nozzles.
The fuel regulator contains a spring loaded diaphragm valve with pressurised
fuel on one side of the diaphragm and manifold vacuum acting...

DESCRIPTION AND OPERATION
DEFENDER V8i4.17
Purge valve
The vehicle is equipped with an evaporative emission control system designed
to prevent vapour loss from the fuel tank. Fuel tank vapour is passed through a
charcoal canister which traps fuel vapour. The vapours trapped by the charcoal
canister is drawn in to the engine through the purge valve and burnt in the
combustion chamber.
The ECM controls the opening of the purge valve to allow venting of the
charcoal canister. The ECM pulses the purge valve...

DESCRIPTION AND OPERATION
4.18
DEFENDER V8i
DIAGNOSTIC SOCKET
DESCRIPTION
The diagnostic socket is located below the passenger compartment fuse box.
The connector is constructed to ISO standard and allows the attachment of
TestBook or any other ISO standard scantool. The diagnostic socket allows
diagnostic information stored in any of the vehicles ECUs to be retrieved. It
also allows engine tuning and fault diagnosis to be carried out via the engine
control module (ECM).
OPERATION
Feed from the positive...

DESCRIPTION AND OPERATION
DEFENDER V8i4.19
AIR CONDITIONING
DESCRIPTION
The air conditioning (A/C) system fitted to the Defender 50LE operates
independently of the standard heating and ventilation system. Controlled by 2
switches mounted in the centre of the fascia, the A/C system will only operate
when the engine is running and the blower control is in at least position 1.
The blower control is a 3 position switch, and works in conjunction with the
temperature control. Temperature control is by a...