1999 LAND ROVER DEFENDER shaft

18ENGINE MANAGEMENT SYSTEM
18
DESCRIPTION AND OPERATION ELECTRONIC UNIT INJECTOR (EUI)
The EUI’s are located in the top of the engine inside the camshaft cover. There is one EUI per cylinder. They inject
finely atomised fuel directly into the combustion chamber. Each EUI has its own electrical connection, which is
linked to a common harness also located under the camshaft cover. Each of the EUI’s has its own 5 letter grading
code. This code is used so that greater EUI precision is achieved.
Using an injection timing map within its memory and information from the CKP sensor the ECM is able to
determine precise crankshaft angle. When the ECM determines the crankshaft speed and position it closes the
spill valve within the EUI. Fuel pressure rises inside the EUI to a predetermined limit of 1500 bar (22,000 lbf.in
2)on
pre EU3 models, and 1750 bar (25,500 lbf.in2) on EU3 models . At this limit the pintle lifts off its seat allowing the
fuel to inject into the combustion chamber. The ECM de-energises the spill valve to control the quantity of fuel
delivered. This causes a rapid pressure drop within the EUI which allows the EUI return spring to re-seat the
pintle, ending fuel delivery.
The electrical circuit that drives the EUI works in two stages depending on battery voltage. If battery voltage is
between 9 and 16 volts the EUI’s will provide normal engine performance. If however battery voltage falls to
between 6 and 9 volts on pre EU3 models, EUI operation is restricted to a limit of 2100 rev/min. On EU3 models,
EUI operation is restricted to idle. If the vehicle is fitted with a new ECM, the EUI grades for that specific vehicle
must be downloaded to the new ECM using TestBook. In the event of the engine failing to rev above 3000 rev/min
it is probable that the EUI grading has not been completed.
Input / Output
Input to the EUI takes the form of both mechanical and electrical signals. The mechanical input to the EUI is diesel
fuel via the fuel pump operating at approximately 4 to 5 bar (58 to 72 lbf.in
2). Each of the EUI’s is operated
mechanically by an overhead camshaft to enable injection pressures of up to 1500 bar (22,000 lbf.in2) on pre EU3
models, and 1750 bar (25,500 lbf.in2) on EU3 models, to be achieved. The ECM controls the EUI’s to ensure that
fuel delivery is precise and as intended.
The EUI’s earth paths are as follows:
EUI 1 (C0522-1) via the ECM (C0158-25) on a yellow wire.
EUI 2 (C0523-1) via the ECM (C0158-26) on a yellow/brown wire.
EUI 3 (C0524-1) via the ECM (C0158-27) on a yellow/blue wire.
EUI 4 (C0525-1) via the ECM (C0158-24) on a yellow/red wire.
EUI 5 (C0526-1) via the ECM (C0158-1) on a yellow/purple wire.
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18ENGINE MANAGEMENT SYSTEM
28
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:
Cold starting.
Hot starting.
Idle.
Wide open throttle.
Acceleration.
Adaptive strategy.
Backup 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 TP 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, the TP
sensor, the ECT sensor, the 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.
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:
CKP information.
Injection timing map information.
FT information.
ECT 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 into the cylinder. The ECM uses CKP information as follows:
To calculate engine speed.
To determine engine crankshaft position.
Engine speed and crankshaft position allows the ECM to determine fuel injection timing.
The ECM also uses ECT and FT information to allow optimum fuel delivery and injection control for all engine
coolant and fuel temperatures.
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18ENGINE MANAGEMENT SYSTEM
2
REPAIR SENSOR - CRANKSHAFT SPEED AND POSITION
(CKP)
Service repair no - 18.30.12
Remove
1.Disconnect CKP sensor multiplug.
2.Remove bolt, remove CKP sensor from gearbox
housing and discard’O’ring.
3.If fitted, collect spacer.
Refit
4.Clean gearbox housing and CKP sensor.
5.If fitted, refit spacer.
6.Fit new’O’ring, position CKP sensor to gearbox
housing and tighten bolt to10 Nm (7 lbf.ft).
7.Connect sensor multiplug.
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FUEL SYSTEM
7
DESCRIPTION AND OPERATION INJECTORS
1.Solenoid housing
2.Electrical connector
3.Push rod socket
4.Push rod return spring
5.Housing
6.Fuel delivery port7.Fuel return port
8.Nozzle cap nut
9.Copper washer
10.Nozzle
11.’O’ring
12.Cap screw
The five injectors are located in the cylinder head adjacent the camshaft, with the nozzle of each injector
protruding directly into the cylinder. Each injector is sealed into the cylinder head with a’O’ring and copper
washer and secured with a clamp and bolt.
Each injector is operated mechanically by an overhead camshaft and rocker, and electrically by a solenoid
controlled by the ECM. Each injector is supplied with pressurised fuel from the pump via the regulator housing and
internal drillings in the cylinder head.
The solenoid housing is secured to the injector body with two cap screws and is a sealed unit. It has a two pin
electrical connector on its top face.
The injector body is machined from a forging. The body has a machined central bore which locates the push rod.
A thread on the outer diameter provides the attachment for the nozzle cap nut. The body also provides attachment
for the solenoid housing.
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19FUEL SYSTEM
8
DESCRIPTION AND OPERATION The injector push rod is operated from the rocker and cam assembly by a sprocket. The push rod is located in the
housing bore and retained in its extended position by a push rod return spring. The powerful spring ensures that
the push rod socket is always in contact with the rocking lever and the cam.
The lower part of the injector housing locates the spring loaded nozzle. The nozzle is retained in the housing by a
nozzle cap nut which is screwed onto the housing. The nozzle cap nut has four holes around its circumference
which connect to the fuel pump drilling in the cylinder head. The injector housing has ports located above the
nozzle cap nut which connect with the fuel delivery drilling in the cylinder head. An’O’ring seals the injector in the
machined location in the cylinder head and a copper washer seals the injector from the combustion chamber.
The injectors are supplied with pressurised fuel from the fuel pump via the pressure regulator housing and internal
drillings in the cylinder head. Each injector sprays fuel directly into the cylinder at approximately 1500 bar (22000
lbf.in) atomising the fuel and mixing it with intake air prior to combustion.
The camshaft and rocker arrangement depresses the push rod which pressurises the fuel within the injector.
When the injector is required to inject fuel into the cylinder, the ECM energises the solenoid which closes a valve
within the solenoid housing. The closure of the valve stops the fuel entering the return line to the pump, trapping it
in the injector. The compression of the fuel by the push rod causes rapid pressurisation of the fuel which lifts the
injector nozzle, forcing the fuel into the cylinder at high pressure. The ECM controls the injection timing by altering
the time at which the solenoid is energised and the injection period by controlling the period for which the solenoid
is energised.
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FUEL SYSTEM
11
DESCRIPTION AND OPERATION OPERATION
The low pressure stage of the fuel pump draws fuel from the swirl pot and pumps it into the fuel filter. The high
pressure stage of the fuel pump draws the fuel from the fuel filter and pumps it along the fuel feed pipe to the
cylinder head.
The fuel enters the cylinder head through a connection on the fuel pressure regulator housing and supplies each
injector with pressurised fuel. The fuel pressure regulator maintains the fuel pressure at the injectors at 4 bar (58
lbf.in) by returning excess fuel back to the fuel filter. The returned fuel passes through the fuel cooler in the engine
compartment before it passes to the fuel filter.
When the engine is running, each injector is operated by an overhead camshaft which depresses a push rod in
each injector at a timed interval. When the cam has depressed the push rod and the push rod is returning to its
extended position, fuel is drawn from the fuel supply drilling in the injector.
When the ECM determines that injection is required, the ECM transmits an electrical pulse which energises the
fast acting solenoid, closing the spill valve on the injector and locking fuel in the injector body. As the cam begins
to depress the push rod, the fuel in the injector is rapidly pressurised. When the pressure exceeds the nozzle
spring pressure, the nozzle opens and injects fuel at very high pressure into the cylinder.
When the ECM determines that the injection period should end, the solenoid is rapidly de-energised, opening the
spill valve on the injector and allowing fuel to pass into the return circuit.
The ECM controls the injection timing by altering the time at which the solenoid is energised, and the injection
period by controlling the period for which the solenoid is energised.
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FUEL SYSTEM
5
REPAIR TURBOCHARGER
Service repair no - 19.42.01
Remove
1.Remove battery cover.
2.Disconnect battery negative lead.
3.Remove 3 bolts and remove engine acoustic
cover.
4.Release clip and disconnect breather hose from
camshaft cover.
5.Release clips and disconnect air flow meter from
air filter.
6.Disconnect multiplug from air flow meter.
7.Loosen clip screw and remove air inlet hose
from turbocharger.
8.Remove 3 bolts and remove exhaust manifold
heat shield.
9.Release clip and disconnect vacuum hose from
turbocharger wastegate.
10.Loosen clip screw and release air outlet hose
from turbocharger.
11.Remove turbocharger oil feed banjo bolt and
discard sealing washers.
12.Remove 3 nuts and release exhaust front pipe
from turbocharger and discard gasket.
13.Remove 3 nuts securing turbocharger to exhaust
manifold.
14.Loosen and unscrew turbocharger drain pipe
union from cylinder block.
15.Remove turbocharger and discard gasket.
16.Remove 2 bolts and remove turbocharger oil
drain pipe. Discard gasket.
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FUEL SYSTEM
7
REPAIR Refit
7.Clean air flow meter faces.
8.Fit new’O’ring to air filter.
9.Clean AAP sensor.
10.Using new’O’ring, fit AAP sensor and tighten
screws.
11.Position air filter assembly and secure in
grommets.
12.Position air flow meter and secure clips.
13.Position intake hose to air filter and tighten clip
screw.INJECTOR - SET
Service repair no - 19.60.12
Remove
1.Remove cooling fan.See COOLING SYSTEM,
Repair.
2.Remove rocker shaft.See ENGINE , Repair.
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 Torx bolt securing injector unit to
cylinder head.
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