1999 LAND ROVER DEFENDER heater

18ENGINE MANAGEMENT SYSTEM
24
DESCRIPTION AND OPERATION GLOW PLUGS
The 4 glow plugs are located in the engine block on the inlet side, in cylinders 1 to 4. Cylinder 5 has no glow plug.
The glow plugs are a vital part of the engine starting strategy. The purpose of the glow plugs are:
Assist cold engine start.
Reduce exhaust emissions at low engine load/speed.
The main part of the glow plug is a tubular heating element that protrudes into the combustion chamber of the
engine.The heating element contains a spiral filament that is encased in magnesium oxide powder. At the tip of
the tubular heating element is the heater coil. Behind the heater coil and connected in series is a control coil. The
control coil regulates the heater coil to ensure that it does not overheat and cause a possible failure. The glow
plug circuit has its own control relay, located underneath the RH front seat.
Pre-heat is the length of time the glow plugs operate prior to engine cranking. The ECM controls the pre-heat time
of the glow plugs based on battery voltage and coolant temperature information via the glow plug relay.
Post-heat is the length of time the glow plugs operate after the engine starts. The ECM controls the post-heat time
based upon ECT information. If the ECT fails the ECM will operate pre-post heat time strategies with default
values from its memory. In this case, the engine will be difficult to start.
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ENGINE MANAGEMENT SYSTEM
25
DESCRIPTION AND OPERATION Input / Output
The glow plugs receive a feed from the glow plug relay (C0215-3) on a yellow/black then individual black wires.
The ECM provides the earth path for the glow plug relay (C0151-6), working in tandem with the Alarm ECU. The
supply voltage heats the coils to approximately 1000°C (1832°F). The glow plug circuit is wired in parallel, the
body of each glow plug is screwed directly into the engine block which provides each glow plug with an earth path.
The glow plugs can fail in one or more of the following ways:
Heater coil open circuit.
Control coil open circuit.
Poor earth quality.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
Harness fault.
Relay windings open circuit.
Incorrect relay fitted.
In the event of a glow plug failure, any of the following symptoms may be observed:
Difficult starting.
Excessive smoke emissions after engine start.
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19 - FUEL SYSTEM
CONTENTS
Page
DESCRIPTION AND OPERATION
COMPONENT LOCATION 1...................................................................................
DESCRIPTION 2.....................................................................................................
FUEL PUMP AND FUEL GAUGE SENDER 3........................................................
FUEL PRESSURE REGULATOR 5........................................................................
INJECTORS 7.........................................................................................................
FUEL FILTER 9.......................................................................................................
WATER SENSOR 10..............................................................................................
OPERATION 11......................................................................................................
ADJUSTMENT
HEATER PLUG TEST 1..........................................................................................
FUEL SYSTEM - BLEED 1.....................................................................................
FUEL TANK - DRAIN 2...........................................................................................
REPAIR
ELEMENT - AIR FILTER 1......................................................................................
SENSOR - FUEL TEMPERATURE 1......................................................................
SWITCH - INERTIA - FUEL CUT OFF 2.................................................................
SENSOR - MASS AIR FLOW (MAF) 2....................................................................
SENSOR - COMBINED MAP AND IAT 3................................................................
SENSOR - AMBIENT AIR PRESSURE (AAP) 3.....................................................
ELEMENT - FUEL FILTER 4...................................................................................
COOLER - FUEL 4..................................................................................................
TURBOCHARGER 5...............................................................................................
FILTER ASSEMBLY - AIR 6...................................................................................
INJECTOR - SET 7.................................................................................................
HEATER PLUGS - SET 9.......................................................................................
INTERCOOLER 9...................................................................................................
POTENTIOMETER - THROTTLE 10......................................................................
PUMP - FUEL 10.....................................................................................................
REGULATOR - FUEL PRESSURE 11....................................................................
FUEL TANK 12.......................................................................................................
NECK - FUEL TANK FILLER 14.............................................................................
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FUEL SYSTEM
3
DESCRIPTION AND OPERATION FUEL PUMP AND FUEL GAUGE SENDER
1.Fuel burning heater feed pipe (not used)
2.Air bleed connection (natural)
3.HP feed connection (green)
4.LP feed connection (blue)
5.LP return connection (black)
6.Pump feed pipe.
7.Spring
8.Fuel gauge sender unit9.Swirl pot
10.Gauze filter
11.Fuel gauge sender float
12.Electrical connections
13.HP/LP two stage pump
14.Pump LP return pipe
15.Electrical connector
The fuel pump is a self priming, wet type, two stage pump, which is emersed in fuel in the tank. It operates at all
times when the ignition switch is in position’II’. If the engine is not started, the ECM will’time-out’after three
minutes and de-energise the fuel pump relay.
The fuel pump assembly is retained with a locking ring and sealed with a rubber seal. The locking ring requires a
special tool for removal and refitment. The fuel gauge sender is integral with the fuel pump. The sender is
submerged in the fuel and is operated by a float which moves with the fuel level in the tank.
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FUEL SYSTEM
1
ADJUSTMENT HEATER PLUG TEST
Service repair no - 19.90.20.01
Check
1. Test out of engine
2.Remove heater plug.See Repair.
3.UsingLRT-12-511,connect RED lead to battery
’+’positive and the BLACK lead to battery’-’
negative.
4.Position heater plug into tester and retain with
spring loaded bar.
5.Connect YELLOW lead to heater plug terminal.
6.Press red button on tester and note ammeter
reading. Keep button depressed, heater plug tip
should start to glow after 5 seconds
CAUTION: The heater plug tip must glow
first, if it fails to do so, replace heater plug.
7.The ammeter reading should show an initial
current draw of 25 amps, which should fall to 12
amps after 20 seconds.
8.Refit heater plug.See Repair.FUEL SYSTEM - BLEED
Service repair no - 19.50.07
Fuel Purging Procedure
1.If the vehicle runs out of fuel, or the fuel level is
so low that the fuel system draws air into the fuel
rail, the fuel rail will need to be purged before the
engine will start. This can be achieved by
following a set procedure. The process does not
require the use of any specialist equipment and
can be performed by the driver of the vehicle.
The process is as follows:
2.Switch off ignition and wait 15 seconds.
3.Turn ignition key to position 2 and wait 3
minutes, (this ensures that the fuel system
purges all the air from the fuel rail within the
cylinder head).
4.Depress the throttle pedal to more than 90% of
its total travel, (to the throttle stop).
5.Crank the engine keeping the throttle pedal
depressed.
NOTE: This operation is controlled by the
ECM and it is important that the purging
operation is not carried out on a vehicle
that has not run out of fuel. If it is carried out
unnecessarily it can lead to the engine flooding
and failing to start.
This operation will be cancelled:
6.As soon as engine speed exceeds 600 rev/min.
7.The driver allows the throttle pedal to close to a
position less than 90% of its travel.
8.The ignition key is released from the start
position.
NOTE: The engine must not be cranked for
more than 30 seconds in any one period.
9.Repeat the above procedure if the engine fails to
start.
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FUEL SYSTEM
9
REPAIR HEATER PLUGS - SET
Service repair no - 19.60.31
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Remove battery cover.
3.Disconnect battery negative lead.
4.Disconnect 4 heater plug leads.
5.Loosen and remove 4 heater plugs.
Refit
6.Throughly clean heater plugs and seating area
in cylinder head.
7.Apply a suitable anti-seize compound to threads
of heater plugs.
8.Fit heater plugs and tighten to16 Nm (12 lbf. ft)
.
9.Connect heater plug leads.
10.Fit engine acoustic cover.
11.Reconnect battery negative lead.
12.Fit battery cover.INTERCOOLER
Service repair no - 19.42.15
Remove
1.Remove radiator.See COOLING SYSTEM,
Repair.
2.Release clip and remove air hose from
intercooler.
Refit
3.Position air hose to intercooler and secure with
clip.
4.Fit radiator.See COOLING SYSTEM, Repair.
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COOLING SYSTEM
3
DESCRIPTION AND OPERATION
NOTE: Inset A shows differences for Pre
EU3 models
1.Pressure cap
2.Overflow pipe
3.Heater return hose
4.Heater matrix
5.Heater inlet hose
6.Oil cooler return pipe - EU3 models
7.Connecting hose
8.Oil cooler housing assembly
9.Heater inlet pipe
10.Connecting hose
11.Outlet housing
12.Engine Coolant Temperature (ECT) sensor
13.Bleed screw
14.Radiator top hose
15.Radiator - upper
16.Intercooler
17.Gearbox oil cooler
18.Radiator - lower
19.Viscous fan
20.Drain plug
21.Connecting hose
22.Fuel cooler feed hose
23.Radiator bottom hose
24.Thermostat housing
25.Connecting hose
26.Coolant pump feed pipe
27.Coolant by-pass pipe
28.Radiator bleed pipe
29.Connecting hose
30.Coolant pump
31.Fuel cooler
32.Heater/expansion tank return hose
33.Expansion tank
34.EGR Cooler - EU3 models
35.Connecting hose - EU3 models
36.Connecting hose - EU3 models
37.Hose - EGR Cooler to oil cooler return pipe -
EU3 models
38.Radiator lower feed hose - Pre EU3 models
39.Oil cooler return pipe - Pre EU3 models
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COOLING SYSTEM
5
DESCRIPTION AND OPERATION A - EU 3 Models
B- Pre EU3 Models
GENERAL
The cooling system used on the Diesel engine is a pressure relief by-pass type system which allows coolant to
circulate around the engine block and heater circuit when the thermostat is closed. With coolant not passing
through the by-pass or the radiator promotes faster heater warm-up which in turn improves passenger comfort.
A coolant pump is mounted on a casting behind the PAS pump and is driven from the PAS pump at crankshaft
speed by the auxiliary drive belt. The pump mounting casting connects with passages in the cylinder block and
pumps coolant from the radiator through the cylinder block.
A viscous fan is attached to an idler pulley at the front of the engine. The fan is attached to a threaded spigot on
the pulley with a right hand threaded nut. The fan draws air through the radiator to assist in cooling when the
vehicle is stationary. The fan rotational speed is controlled relative to the running temperature of the engine by a
thermostatic valve regulated by a bi-metallic coil.
The cooling system uses a 50/50 mix of anti-freeze and water.
Thermostat Housing
A plastic thermostat housing is located behind the radiator. The housing has three connections which locate the
radiator bottom hose, top hose and coolant pump feed pipe. The housing contains a wax element thermostat and
a spring loaded by-pass flow valve.
Thermostat - Main valve
The thermostat is used to maintain the coolant at the optimum temperature for efficient combustion and to aid
engine warm-up. The thermostat is closed at temperatures below approximately 82°C (179°F). When the coolant
temperature reaches approximately 82°C the thermostat starts to open and is fully open at approximately 96°C
(204°F). In this condition the full flow of coolant is directed through the radiator.
The thermostat is exposed to 90% hot coolant from the engine on one side and 10% cold coolant returning from
the radiator bottom hose on the other side.
Hot coolant from the engine passes from the by-pass pipe through four sensing holes in the flow valve into a tube
surrounding 90% of the thermostat sensitive area. Cold coolant returning from the radiator, cooled by the ambient
air, conducts through 10% of the thermostat sensitive area.
In cold ambient temperatures, the engine temperature is raised approximately 10°C (50°F) to compensate for the
heat loss of 10% exposure to the cold coolant returning from the radiator bottom hose.
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