fuel LAND ROVER DEFENDER 1999 Repair Manual
[x] Cancel search | Manufacturer: LAND ROVER, Model Year: 1999, Model line: DEFENDER, Model: LAND ROVER DEFENDER 1999Pages: 667, PDF Size: 8.76 MB
Page 245 of 667
18ENGINE MANAGEMENT SYSTEM
22
DESCRIPTION AND OPERATION SWITCH - BRAKE PEDAL
The brake pedal switch is located at the rear of the brake pedal box, and activates when the brake pedal is
operated. The ECM uses the signal from the brake pedal to activate the brake lamps and to limit fuelling under
braking.
The brake pedal switch can fail in any of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to earth.
SWITCH - CLUTCH PEDAL
The clutch pedal switch is located on the clutch master cylinder and is activated when the clutch pedal is operated.
The ECM uses the signal from the clutch pedal switch to provide surge damping during gear change. Surge
damping stops engine speed rising dramatically (engine flaring) during gear change. Surge damping assists
driveability as follows:
Smoother gear change.
Greater exhaust gas emission control.
Improved fuel consumption.
Input / Output
When the clutch pedal is in the rest position, the clutch switch is closed. This allows a feed to flow from the switch
(C0667-1) to the ECM (C0658-35) on a black/white wire. When the clutch pedal is pressed the switch contacts
open, cutting the feed to the ECM.
The clutch pedal switch can fail in any one of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
In the event of a clutch pedal switch failure surge damping will be inactive.
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Page 249 of 667
18ENGINE MANAGEMENT SYSTEM
26
DESCRIPTION AND OPERATION TURBOCHARGER
1.Exhaust gas from manifold
2.Studs to exhaust manifold
3.Turbocharger cast iron housing
4.Wastegate valve linkage
5.Exhaust gas out to front exhaust pipe6.Compressed air intake
7.Fresh air intake
8.Turbocharger aluminium alloy housing
9.Wastegate valve vacuum port
The Td5 engine utilises a Garrett GT20 turbocharger with an electronically controlled wastegate modulator to
improve engine performance. The turbocharger uses the engines exhaust gas to spin a turbine at very high
speed. This causes inlet air on the other side of the turbine to be drawn in through the turbocharger intake for
compression.The inlet air is carried round by the vanes of the compressor and then thrown out under centrifugal
force from the turbochargers outlet duct. This compression of air enables a greater quantity of air to be delivered
to the inlet manifold via an intercooler. Combustion is improved through better volumetric efficiency. The use of a
turbocharger improves fuel consumption and increases engine torque and power. Exhaust noise is also reduced
due to the smoothing out of exhaust pulsations.
The rear cast iron body of the turbocharger housing connects to a port on the exhaust manifold at the LH side of
the cylinder head by three studs and nuts. The interface between the exhaust manifold and the turbocharger
housing is separated by a metal gasket. The exhaust outlet of the turbocharger is located at the bottom of the
turbocharger cast iron housing. It is connected to the exhaust system front downpipe and is attached by three
studs and nuts. The interface between the turbocharger housing and the exhaust front pipe is separated by a
metal gasket.
The front casing of the turbocharger is constructed from aluminium alloy and is connected to the air inlet duct by a
metal band clip. The compressed air outlet is connected to the intercooler by a metal pipe which has rubber hose
extensions at each end attached by metal band clips.
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Page 251 of 667
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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Page 254 of 667
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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Page 256 of 667
FUEL SYSTEM
1
DESCRIPTION AND OPERATION COMPONENT LOCATION
1.HP stage
2.LP stage
3.Filters
4.Jet pump
5.Fuel pump and fuel gauge sender unit
6.LP return connection
7.LP feed connection8.HP feed connection
9.Air bleed connection
10.Fuel filter
11.Water sensor
12.Fuel cooler
13.Fuel pressure regulator
14.Electronic Unit Injectors
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Page 257 of 667
19FUEL SYSTEM
2
DESCRIPTION AND OPERATION DESCRIPTION
General
The fuel delivery system comprises a fuel tank, fuel pump, fuel pressure regulator, five injectors and a fuel filter.
The system is controlled by the ECM, which energises the fuel pump relay and controls the operation and timing
of each injector solenoid.
Unlike other Diesel engines, the Td5 has no injection pump. The diesel direct injection system receives fuel at
pressure from a two stage fuel pump located in the fuel tank. The system incorporates a fuel return to the fuel
pump, via a fuel cooler attached to the inlet manifold, and a fuel filter. A fuel pressure regulator is located in a
housing on the rear of the cylinder head. The regulator maintains the fuel delivered to the injectors at a constant
pressure and returns excess fuel back to the fuel filter and pump via the fuel cooler.
A fuel filter is positioned on the chassis longitudinal, below the RH rear wheel arch. The fuel feed and return to and
from the engine passes through the filter. The filter also incorporates a water sensor, which illuminates a warning
lamp in the instrument pack.
A moulded fuel tank is located at the rear underside of the vehicle between the chassis longitudinals. The tank
provides the attachment for the fuel pump and the fuel gauge sender unit, which is located inside the tank.
Fuel Tank and Breather
The fuel tank and breather system is a major part of the fuel delivery system. The fuel tank and breathers are
located at the rear of the vehicle between the chassis longitudinals.
Fuel Tank
The moulded fuel tank is made from High Molecular Weight (HMW) High Density Polyethylene (HDPE), and is
manufactured using a proportion of recycled plastic.
The tank is held in position by a metal cradle which is secured to the chassis cross members by four bolts, two
holding the front of the cradle in position, two holding the rear. The fuel tank has a useable capacity of 75 litres
(16.5 gallons).
An aperture in the top surface of the tank allows for the fitment of the fuel pump and fuel gauge sender unit, which
is retained with a locking ring. A reflective metallic covering is attached to the tank with three scrivets to shield the
tank from heat generated by the exhaust system.
Fuel Tank Breather System
The fuel tank filler tube incorporates a tank vent which allows air and fuel vapour displaced from the tank when
filling to vent to atmosphere via the filler neck.
A breather spout within the tank controls the tank’Full’height. When fuel covers the spout it prevents fuel vapour
and air from escaping from the tank. This causes the fuel to’back-up’in the filler tube and shuts off the filler gun.
The position of the spout ensures that when the filler gun shuts off, a vapour space of approximately 10% of the
tanks total capacity remains. The vapour space ensures that the Roll Over Value (ROV) is always above the fuel
level and vapour can escape and allow the tank to breathe.
The ROV is welded to the top surface of the tank. It is connected by a tube to the filler tube, which in turn is
connected to the atmospheric vent pipe. The ROV allows fuel vapour to pass through it during normal vehicle
operation. In the event of the vehicle being overturned the valve shuts off, sealing the tank and preventing fuel
from spilling from the atmospheric vent pipe.
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Page 258 of 667
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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Page 259 of 667
19FUEL SYSTEM
4
DESCRIPTION AND OPERATION Fuel Pump
The fuel pump assembly comprises a top cover which locates the electrical connector, and four fuel pipe
couplings. The top cover is attached to a plastic cup shaped housing and retained on three sliding clips. Two coil
springs are located between the cover and the housing and ensure that the fuel pump remains seated positively at
the bottom of the tank when installed.
The housing locates the two stage fuel pump and also the fuel gauge sender unit. The lower part of the housing is
the swirl pot which maintains a constant level of fuel at the fuel pick-up. A coarse filter is located in the base of the
housing and prevents the ingress of contaminants into the pump and the fuel system from the fuel being drawn
into the pump. A fine filter is located in the intake to the low pressure stage to protect the pump from
contaminants. Flexible pipes connect the couplings on the top cover to the pump.
A non-return valve is located in the base of the housing. When the fuel tank is full, fuel pressure keeps the valve
lifted from its seat, allowing fuel to flow into the swirl pot. As the tank level reduces, the fuel pressure in the tank
reduces causing the valve to close. When the valve is closed, fuel is retained in the swirl pot, ensuring that the
swirl pot remains full and maintains a constant supply to the fuel pump.
The two stage pump comprises a high and low pressure stage. The low pressure stage draws fuel from the swirl
pot through a filter. The low pressure stage pumps fluid at a pressure of 0.75 bar (10.9 lbf.in) and a flow of 30
litres/hour (8 US Gallons/hour) to the fuel filter. A proportion of the fuel from the low pressure stage also passes,
via a restrictor, through a jet pump which keeps fuel circulating in the swirl pot. The high pressure stage draws the
low pressure fuel from the fuel filter and pressurises it to a pressure of 4.0 bar (58 lbf.in). The pressurised fuel is
then passed from the pump to the injectors at a flow of 180 litres/hour (47.6 US Gallons/hour). A fuel pressure
regulator is located at the rear of the engine and ensures that the delivery pressure remains at 4.0 bar (58 lbf.in)
by controlling the amount of fuel returning to the fuel tank.
The fuel pump has a maximum current draw of 15 Amps at 12 Volts and is supplied a feed (C0114-1) from the fuel
pump relay (C0730-2) on a white/purple wire.
Fuel Gauge Sender
The fuel gauge sender unit comprises a rotary potentiometer operated by a float. The float rises and falls with the
fuel level in the tank and moves the potentiometer accordingly.
A feed is supplied to the fuel gauge sender (C0114-1) by the fuel pump relay (C0730-2) on a purple/white then
white/purple wire. The sender is earthed (C0114-3) on a slate/black wire via header 287. The output voltage
(C0114-2) from the sender to the instrument pack (C1061-3) varies in relation to the fuel level. This output voltage
is connected to the fuel gauge C1054-2). The fuel gauge receives a battery voltage input (C1054-3) on a
white/green wire. This is compared with the output voltage from the potentiometer. The difference between the two
voltages determines the deflection of the fuel gauge pointer.
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Page 260 of 667
FUEL SYSTEM
5
DESCRIPTION AND OPERATION FUEL PRESSURE REGULATOR
NOTE: Non EU3 Model illustrated.
1.Gasket
2.Housing
3.Bolt
4.Fuel feed union and pipe
5.Fuel return union and hose
6.Fuel temperature sensor
7.Bonded seal8.’O’ring
9.Circlip
10.Fuel pressure regulator
11.’O’ring
12.’O’ring
13.Gauze filter
The fuel pressure regulator is located in a cast alloy housing which is attached to the rear right hand corner of the
cylinder head with three flanged bolts and sealed with a metal gasket. Two ports in the housing connect with ports
in the cylinder head for fuel pressure feed and return. A gauze filter is located in the pressure feed port in the
cylinder head, and filters the fuel before it reaches the injectors. The filter is a fit for life item but can be changed if
required. An’O’ring is located in a recess in the cylinder head and provides additional sealing for the pressure
feed port between the gauze filter, the cylinder head, and the housing.
A union and pipe is attached to the feed port in the housing and connects with a quick release coupling to the fuel
pressure feed pipe from the fuel pump. A second union and hose is located in the return port and provides the fuel
return connection to the fuel cooler. A third port provides location for the fuel temperature sensor, which is sealed
to the housing with a bonded seal. The fuel temperature sensor is used by the ECM for engine management.
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Page 261 of 667
19FUEL SYSTEM
6
DESCRIPTION AND OPERATION The fuel pressure regulator is located in a machined port in the lower part of the housing. The regulator is sealed
in the housing with two’O’rings and secured with an internal clip.
The regulator maintains the fuel pump delivery pressure at 4 bar (58 lbf.in
2). When the fuel pressure exceeds 4
bar (58 lbf.in2), the regulator opens and allows fuel to return to the fuel tank via the fuel cooler. The fuel returned
from the regulator is directed back into the fuel filter before being drawn by the high pressure stage of the fuel
pump and directed back to the injectors. A special tool can be attached to the regulator housing fuel feed port and
allows for the fitment of a suitable gauge to measure fuel pump delivery pressure.
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