fuel pump LAND ROVER DEFENDER 1999 User Guide
[x] Cancel search | Manufacturer: LAND ROVER, Model Year: 1999, Model line: DEFENDER, Model: LAND ROVER DEFENDER 1999Pages: 667, PDF Size: 8.76 MB
Page 241 of 667
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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ENGINE MANAGEMENT SYSTEM
21
DESCRIPTION AND OPERATION RELAY - FUEL PUMP
The fuel pump relay is located in the engine compartment fuse box. It switches on the fuel pump to draw fuel from
the tank to the electronic unit injectors (EUI).
Input / Output
The fuel pump relay is a 4 pin normally open relay. The fuel pump relay (C0730-4) is provided with a feed by the
main relay (C0063-78) via header 291 on a brown/orange wire. An earth path is provided for the fuel pump relay
(C0730-6) via the ECM (C658-5) on a blue/purple wire. This energises the fuel pump relay and allows a feed to be
provided to the fuel pump. When the ECM interrupts the earth, the relay is de-energised and the fuel pump stops
operating.
The fuel pump relay can fail in one or more of the following ways:
Relay open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
Broken relay return spring.
In the event of a fuel pump relay failure any of the following symptoms may be observed:
Engine will crank but not start.
If the engine is running, it will stop.
RELAY - MAIN
The main relay is located in the engine compartment fuse box and supplies battery voltage to the following:
The ECM.
The MAF sensor.
Fuel pump relay.
Input / Output
The main relay is a 4 pin normally open relay, which must be energised to provide a voltage to the ECM. The main
relay (C0063-86) is provided with an earth path via a transistor within the ECM (C0658-21) on a blue/red wire.
When the earth path is completed, the relay is energised and supplies the ECM (C0658-3, C0658-22 & C0658-27)
with a feed on brown/orange wires via header 291.
The main relay can fail in the following ways:
Relay open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
Broken relay return spring.
In the event of a main relay failure any of the following symptoms may be observed:
Engine will crank but not start.
If the engine is running, it will stop.
For the ECM start up to take place the ignition feed when the switch is in position’II’must be greater than 6.0
volts.
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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
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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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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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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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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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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Page 262 of 667
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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