2002 LAND ROVER DISCOVERY Fuel system

ENGINE MANAGEMENT SYSTEM - TD5
18-1-38 DESCRIPTION AND OPERATION
Operation
Engine management
The ECM controls the operation of the engine using stored information within its memory. This guarantees optimum
performance from the engine in terms of torque delivery, fuel consumption and exhaust emissions in all operating
conditions, while still giving optimum driveability.
The ECM will receive information from its sensors under all operating conditions, especially during:
lCold starting.
lHot starting.
lIdle.
lWide open throttle.
lAcceleration.
lAdaptive strategy.
lBackup strategy for sensor failures.
The ECM receives information from various sensors to determine the current operating state of the engine. The ECM
then refers this information to stored values in its memory and makes any necessary changes to optimise air/fuel
mixture and fuel injection timing. The ECM controls the air/fuel mixture and fuel injection timing via the Electronic Unit
Injectors (EUI), by the length of time the EUI's are to inject fuel into the cylinder. This is a rolling process and is called
adaptive strategy. By using this adaptive strategy the ECM is able to control the engine to give optimum driveability
under all operating conditions.
During cold start conditions the ECM uses ECT information to allow more fuel to be injected into the cylinders, this
combined with the glow plug timing strategy supplied by the ECM facilitates good cold starting.
During hot start conditions the ECM uses ECT and FT information to implement the optimum fuelling strategy to
facilitate good hot starting.
During idle and wide open throttle conditions the ECM uses mapped information within its memory to respond to input
information from the throttle pedal position sensor to implement the optimum fuelling strategy to facilitate idle and wide
open throttle.
To achieve an adaptive strategy for acceleration the ECM uses input information from the CKP sensor, TP sensor,
ECT sensor, MAP/ IAT sensor, and the FT sensor. This is compared to mapped information within its memory to
implement the optimum fuelling strategy to facilitate acceleration.
Immobilisation system
When the starter switch is turned on, the BCU sends a unique security code to the ECM. The ECM must accept this
code before it will allow the engine to operate. If the ECM receives no security code or the ECM receives the incorrect
security code, then the ECM allows the engine to run for 0.5 seconds only. During this operation all other ECM
functions remain as normal.
The ECM operates immobilisation in three states:
l'New.'
l'Secure'.
l'No Code'.
When an ECM is unconfigured it will operate in the 'New' state. When an unconfigured ECM is installed the engine
can be started and operated once only, then the ECM has to be re-configured to either 'secure' or 'no code'
configuration depending on whether a security system is fitted to the vehicle. This is achieved by using TestBook.

ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-39
With the ECM in a 'Secure' state, it will not function unless an alarm system is fitted to the vehicle. A 'Secure' ECM
cannot be configured into a 'No Code' ECM.
With the ECM in a 'No Code' state, it does not require an alarm system to be fitted to allow the engine to operate. If
the ECM senses that an alarm system is fitted it will not start. A 'No Code' ECM can be configured to a 'Secure' ECM
using TestBook. A 'Secure' ECM can not be configured to a 'No Code' state.
Setting up of the ECM immobilisation configurations can only be performed using TestBook.
If a vehicle stalls immediately after starting it is possible that it has been immobilised. This means either:
lThe ECM was configured as 'No Code' but the ECM is receiving a code at its alarm input pin.
lThe ECM received an incorrect code.
lThe ECM was expecting a security code but did not receive one at its alarm input pin.
Fuel delivery/injection control
The fuel delivery/injection control delivers a precise amount of finely atomised fuel to mix with the air in the
combustion chamber to create a controlled explosion.
To precisely control fuel delivery and control fuel injection, the following input conditions must be met:
lCKP information.
lInjection timing map information.
lFT information.
lECT information.
The ECM monitors the conditions required for optimum combustion of fuel in the cylinder from the various sensors
around the engine and then compares it against stored information. From this calculation the ECM can adjust the
quantity and timing of the fuel being delivered to the cylinder.
The ECM uses CKP information as follows:
lTo calculate engine speed.
lTo determine engine crankshaft position.
Engine speed and crankshaft position allows the ECM to determine fuel injection timing.
The ECM also uses ECT information and FT sensor information to allow optimum fuel delivery and injection control
for all engine coolant and fuel temperatures.
Turbocharger control
Turbocharger control is vital to ensure the turbocharger does not over boost the engine. Within the turbocharger is a
wastegate, which when operated by the turbocharger wastegate modulator will open and close a bypass valve
regulating boost pressure.
The turbocharger wastegate modulator, via the ECM, controls boost pressure under the following conditions:
lAcceleration.
lWide open throttle.
lIdle.
lOverrun.
The turbocharger wastegate modulator receives a battery voltage supply from the main relay. The ECM supplies the
earth path in the form of a pulse width modulation (PWM) signal. This signal allows the turbocharger wastegate
modulator to open and close the wastegate. A proportion of the exhaust gas can bypass the turbocharger through
the wastegate, regulating boost pressure.

ENGINE MANAGEMENT SYSTEM - TD5
18-1-50 REPAIRS
2.Disconnect multiplug from AAP sensor.
3.Release 2 clips and remove cover from air
filter.
4.Remove air filter element.
Refit
1.Clean air filter body and cover.
2.Fit new air filter element.
3.Position air cleaner cover and secure clips.
4.Position MAF sensor and secure clips.
5.Connect multiplug to AAP sensor.
Sensor - fuel temperature
$% 19.22.08
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Release fixings and remove battery cover.
3.Disconnect battery earth lead.
4.Disconnect multiplug from fuel temperature
sensor.
5. Thoroughly clean area around fuel
temperature sensor before removal.
6.Remove fuel temperature sensor and discard
sealing washer.
Refit
1.Clean fuel temperature sensor mating faces.
2.Fit new sealing washer and tighten fuel
temperature sensor to 13 Nm (10 lbf.ft) .
3.Connect multiplug to fuel temperature sensor.
4.Connect battery earth lead.
5.Fit battery cover and secure fixings.
6.Fit engine acoustic cover, and secure with
fixings.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-53
Element - fuel filter
$% 19.25.07
Remove
1.Release turnbuckles and remove battery cover.
2.Disconnect battery earth lead.
3.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
4.Clean area around fuel filter.
5.Disconnect multiplug from filter element.
6.Remove fuel filter element.
Refit
1.Clean fuel filter and mating face.
2.Fit new fuel filter element and connect
multiplug.
3.Remove stand(s) and lower vehicle.
4.Connect battery earth lead.
5.Fit battery cover and secure the fixings.
Cooler - fuel
$% 19.25.30
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Remove battery cover.
3.Disconnect battery earth lead.
4.Drain cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
5.Release 3 clips and disconnect 3 coolant hoses
from fuel cooler.
6.Release 2 fuel hoses from fuel cooler.
CAUTION: Always fit plugs to open
connections to prevent contamination.
7.Release vacuum pipe clip from fuel cooler.
8.Noting which bolts are removed from the upper
fixing holes, remove 4 bolts securing fuel cooler
to inlet manifold. Remove cooler.
Refit
1.Clean fuel hose connections.
2.Apply Loctite 242 to the two upper bolts.
3.Position fuel cooler to inlet manifold, fit bolts
and tighten the upper bolts to 18 Nm (13 lbf.ft)
and the lower bolts to 25 Nm (18 lbf.ft).
4.Connect fuel hoses to fuel cooler.
5.Connect coolant hoses to fuel cooler, secure
with clips.
6.Secure vacuum hose to fuel cooler.
7.Refill cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
8.Fit engine acoustic cover and secure with
fixings.
9.Connect battery earth lead.
10.Fit battery cover.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-59
Regulator - fuel pressure
$% 19.45.06
Remove
1.Release turnbuckles and remove battery cover
2.Disconnect battery earth lead.
3.Remove 3 bolts and remove engine acoustic
cover.
4.Remove 2 bolts and remove engine lifting eye.
5.Position cloth to absorb fuel spillage.
6.Release and disconnect hose from fuel cooler. 7.Release and disconnect fuel hose from
pressure regulator.
Always fit plugs to open connections to
prevent contamination.
8.Disconnect multiplug from fuel temperature
sensor.
9.Remove 3 bolts, remove pressure regulator
from cylinder head and collect gasket.
10.Remove and discard 'O' ring and fuel filter.

ENGINE MANAGEMENT SYSTEM - TD5
18-1-60 REPAIRS
11.Remove fuel temperature sensor and discard
sealing washer.
12.Remove fuel hose and fuel pipe and discard 'O'
rings.
Refit
1.Clean fuel pressure regulator and mating face.
2.Clean fuel pipe unions.
3.Using new 'O' rings, fit fuel pipe and fuel hose
to pressure regulator and tighten unions to 25
Nm (18 lbf.ft).
4.Using new sealing washer, fit fuel temperature
sensor and tighten to 14 Nm (10 lbf.ft).
5.Fit new fuel filter and 'O' ring.
6.Using a new gasket, position pressure
regulator and tighten bolts to 25 Nm (18 lbf.ft).
7.Connect multiplug to fuel temperature sensor.
8.Connect fuel hoses to pressure regulator and
fuel cooler.
9.Fit engine lifting eye and tighten bolts to 25 Nm
(18 lbf.ft).
10.Fit engine acoustic cover and tighten bolts to 10
Nm (6 lbf.ft).
11.Connect battery earth lead.
12.Fit battery cover and secure fixings.
Glow plugs
$% 19.60.31
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Release turnbuckles and remove battery cover.
3.Disconnect battery earth lead.
4.Disconnect 4 glow plug leads.
5.Loosen and remove 4 glow plugs.
Refit
1.Thoroughly clean glow plugs and seating area
in cylinder head.
2.Apply a suitable anti-sieze compound to
threads of glow plugs.
3.Fit glow plugs and tighten to 16 Nm (12 lbf. ft).
4.Connect glow plug leads.
5.Fit engine acoustic cover and secure fixings.
6.Connect battery earth lead.
7.Fit battery cover and secure fixings.

ENGINE MANAGEMENT SYSTEM - TD5
REPAIRS 18-1-61
Injectors
$% 19.60.12
Remove
1.Remove cooling fan.

+ COOLING SYSTEM - Td5, REPAIRS,
Fan - viscous.
2.Remove rocker shaft.

+ ENGINE - Td5, REPAIRS, Rocker
shaft assembly.
3.Position container to catch fuel spillage.
4.Disconnect quick release fuel hose connectors
from fuel connector block on cylinder head and
fuel cooler to drain fuel from cylinder head. 5.Disconnect 5 multiplugs from injectors.
6.Remove 5 Torx bolts securing injectors to
cylinder head.
7.Using LRT-12-154/1, remove injectors from
cylinder head. Collect retainers.
8.Using LRT-12-154/4, remove sealing washers
from injectors. Discard sealing washers.
9.Remove and discard 'O' rings from injectors.
10.Rotate engine manually until each cylinder
being worked on is at TDC, and remove excess
fuel from piston bowl using a syringe.

ENGINE MANAGEMENT SYSTEM - TD5
18-1-62 REPAIRS
Refit
1.Clean injector units and mating faces in
cylinder head.
2.Using LRT-12-154/2, fit a new 'O' ring to each
injector.
3.Using LRT-12-154/3, fit a new sealing washer
to each injector.
4.Fit retainer to injector. Carefully fit injector,
ensuring retainer is located on its dowel, and
tighten Torx bolt to 32 Nm (24 lbf.ft)
5.Connect multiplug to injector.
6.Repeat above operations for remaining
injectors.
7.Connect fuel hoses to connector block and fuel
cooler.
8.Programme new injectors using TestBook.
9.Fit rocker shaft.

+ ENGINE - Td5, REPAIRS, Rocker
shaft assembly.
10.Fit cooling fan.

+ COOLING SYSTEM - Td5, REPAIRS,
Fan - viscous.
Switch - cruise control (on/off)
$% 19.75.30
Remove
1.Carefully remove switch from instrument cowl.
2.Disconnect multiplug and remove switch.
Refit
1.Position new switch and connect multiplug.
2.Carefully push switch into instrument cowl.