1999 LAND ROVER DEFENDER warning

18 - ENGINE MANAGEMENT SYSTEM
CONTENTS
Page
DESCRIPTION AND OPERATION
COMPONENT LOCATION 2...................................................................................
DESCRIPTION 5.....................................................................................................
ENGINE CONTROL MODULE (ECM) 6.................................................................
SENSOR - MASS AIR FLOW (MAF) 7....................................................................
SENSOR - AMBIENT AIR PRESSURE AND 8.......................................................
SENSOR - MANIFOLD ABSOLUTE PRESSURE 9................................................
SENSOR - ENGINE COOLANT TEMPERATURE 11.............................................
SENSOR - CRANKSHAFT SPEED AND 12...........................................................
SENSOR - THROTTLE POSITION (TP) 14............................................................
SENSOR - THROTTLE POSITION (TP) 15............................................................
ELECTRONIC UNIT INJECTOR (EUI) 18...............................................................
SENSOR - FUEL TEMPERATURE (FT) 20............................................................
RELAY - FUEL PUMP 21........................................................................................
RELAY - MAIN 21...................................................................................................
SWITCH - BRAKE PEDAL 22.................................................................................
SWITCH - CLUTCH PEDAL 22...............................................................................
MODULATOR - EXHAUST GAS REGULATOR (EGR) 23.....................................
WARNING LAMP - GLOW PLUG 23......................................................................
GLOW PLUGS 24...................................................................................................
TURBOCHARGER 26.............................................................................................
INTERCOOLER 27.................................................................................................
OPERATION 28......................................................................................................
REPAIR
ENGINE CONTROL MODULE (ECM) 1.................................................................
SENSOR - ENGINE COOLANT TEMPERATURE (ECT) 1....................................
SENSOR - CRANKSHAFT SPEED AND POSITION (CKP) 2................................
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ENGINE MANAGEMENT SYSTEM
5
DESCRIPTION AND OPERATION DESCRIPTION
General
An engine control module (ECM) controls the five cylinder direct injection diesel engine, and works on the drive by
wire principal. This means there is no throttle cable, the ECM controls the drivers needs via a signal from the
Throttle Position (TP) sensor on the throttle pedal.
The ECM is a full authoritative diesel specific microprocessor that also incorporates features for air conditioning. In
addition, the ECM supplies output control for the Exhaust Gas Recirculation (EGR) and turbocharger boost
pressure. The ECM has a self diagnostic function, which is able to provide backup strategies for most sensor
failures.
The ECM processes information from the following input sources:
Mass Air Flow (MAF) sensor.
Ambient Air Pressure (AAP) sensor.
Manifold Absolute Pressure (MAP) / Inlet Air Temperature (IAT) sensor.
Engine Coolant Temperature (ECT) sensor.
Crankshaft Speed and Position (CKP) sensor.
Throttle Position (TP) sensor.
Fuel Temperature (FT) sensor.
Air conditioning request.
Air conditioning fan request.
Brake pedal switch.
Clutch pedal switch.
The input from the sensors constantly updates the ECM with the current operating condition of the engine. Once
the ECM has compared current information with stored information within its memory, it can make any adjustment
it requires to the operation of the engine via the following:
Air conditioning clutch relay.
Air conditioning cooling fan relay.
Electronic vacuum regulator solenoid.
Fuel pump relay.
Glow plug warning lamp.
Glow plugs.
Fuel injectors.
Main relay.
Turbocharger wastegate modulator.
Temperature gauge.
The ECM interfaces with the following:
Serial communication link.
Instrument pack.
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ENGINE MANAGEMENT SYSTEM
11
DESCRIPTION AND OPERATION SENSOR - ENGINE COOLANT TEMPERATURE
(ECT)
The ECT sensor is located in the coolant outlet elbow on top of the engine. It provides the ECM with engine
coolant temperature information. The ECM uses this information for the following functions:
Fuelling calculations.
Temperature gauge.
To limit engine operation if coolant temperature is to high.
Cooling fan operation.
Glow plug operating time.
The ECT works as an NTC sensor. As temperature rises, the resistance in the sensor decreases, as temperature
decreases, the resistance in the sensor increases. The ECM compares the voltage signal to stored values and
compensates fuel delivery to ensure optimum driveability at all times.
Inputs / Outputs
The ECT sensor (C0169-2) is provided a feed by the ECM (C0158-7) on a pink/green wire. The sensor is provided
an earth path (C0169-1) via the ECM (C0158-18) on a pink/black wire.
The ECT can fail or supply an incorrect signal if one or more of the following occurs:
Sensor open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
Incorrect mechanical fitting.
Signal fixed above 40°C (104°F) not detected.
Signal fixed below 40°C (104°F) not detected.
In the event of an ECT sensor failure, any of the following symptoms may be observed:
Difficult cold start.
Difficult hot start.
Driveability concerns.
Instrument pack warning lamp illuminated.
Temperature gauge reads excessively hot.
Temperature gauge reads excessively cold.
In the event of a component failure the ECM calculates coolant temperature from the fuel temperature signal. If
this occurs, the limit of engine operation if coolant temperature becomes too high becomes inoperative.
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ENGINE MANAGEMENT SYSTEM
23
DESCRIPTION AND OPERATION MODULATOR - EXHAUST GAS REGULATOR (EGR)
The EGR modulator is located on the RH side inner front wing. It regulates the vacuum source to the EGR valve
allowing it to open or close. The ECM utilises the EGR modulator to control the amount of exhaust gas being
recirculated in order to reduce exhaust emissions and combustion noise. Optimum EGR is usually obtained when
the vehicle is operating at light throttle openings, and the vehicle is cruising at approximately 2000 to 3000
rev/min.
Input / Output
The EGR modulator (C0191-1) receives a feed from the main relay (C0063-87) on a brown/orange wire via header
294. The earth path for the modulator (C0191-2) is controlled by the ECM (C0158-3) on a blue wire. The length of
time the ECM supplies an earth is how long the exhaust gases are allowed to recirculate. The ECM decides how
long to supply the earth by looking at engine temperature and engine load.
The EGR modulator can fail in one or more of the following ways:
Solenoid open circuit.
Short circuit to vehicle supply.
Short circuit to earth.
In the event of an EGR modulator failure, the EGR system will become inoperative.
WARNING LAMP - GLOW PLUG
The glow plug warning lamp is located in the instrument pack. It illuminates to alert the driver that the glow plugs
are being heated prior to the engine being started. The length of time that the lamp illuminates and the glow plugs
are operating prior to cranking is the pre-heat period. The length of time of this period is determined by the ECT
sensor signal, controlled by the ECM.
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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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19FUEL SYSTEM
10
DESCRIPTION AND OPERATION WATER SENSOR
The water sensor has a three pin electrical connector. When the sensor detects water in the fuel filter it illuminates
a warning lamp in the instrument pack.
The water sensor attachment thread has a slot machined down one side. The filter can be purged of water by
partially unscrewing the sensor which aligns the slot in the threads with a corresponding hole in the sensor. When
aligned, water and fuel can flow down the slot and flows from a small cast tube on the side of the sensor.
Re-tightening the sensor mis-aligns the slot and stops the flow of fuel.
The sensor operates by measuring the resistance between its two electrodes, which are submerged in fuel, and
activated by the presence of water. When the ignition switch is moved to position’II’, the warning lamp will
illuminate for approximately 2 seconds to check warning lamp functionality.
When the filter is full with fuel and no water is present, the resistance of the Diesel fuel will show a reading of 15
mA maximum on the feed wire to the instrument pack. When sufficient water surrounds both electrodes, the
resistance of the water will show a reading of 130 mA maximum. This will supply sufficient voltage to the
instrument pack to illuminate the warning lamp, and alert the driver to the presence of water in the fuel system.
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19FUEL SYSTEM
2
ADJUSTMENT FUEL TANK - DRAIN
Service repair no - 19.55.02
1.Remove battery cover.
2.Disconnect both leads from battery, earth lead
first.
WARNING: Fuel vapour is highly
flammable and in contained spaces is also
explosive and toxic. Always have a fire
extinguisher containing FOAM, CO2, GAS OR
POWDER close at hand when handling or draining
fuel.
3.Using a fuel recovery appliance, drain the fuel
from the tank into a sealed container. Follow the
manufacturers instructions for the connection
and safe use of the appliance.
4.Remove filler cap and insert hose into filler neck.
5.Connect bowser earth line. Drain fuel.
6.Connect battery leads.
7.Fit battery cover.
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19FUEL SYSTEM
4
REPAIR ELEMENT - FUEL FILTER
Service repair no - 19.25.07
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery negative lead.
3.Raise rear of vehicle.
WARNING: Support on safety stands.
4.Release fixing and remove fuel filter cover.
5.Clean area around fuel filter.
6.Disconnect multiplug from filter element.
7.Remove fuel filter element.
Refit
8.Clean fuel filter and mating face.
9.Fit new fuel filter element and connect multiplug.
10.Position fuel filter cover and secure with fixing.
11.Remove stand(s) and lower vehicle.
12.Reconnect battery negative lead.
13.Fit and secure battery cover.COOLER - FUEL
Service repair no - 19.25.30
Remove
1.Remove 3 bolts and remove engine acoustic
cover.
2.Remove battery cover.
3.Disconnect battery negative lead.
4.Drain cooling system.See COOLING
SYSTEM, Adjustment.
5.Release 3 clips and disconnect 3 coolant hoses
from fuel cooler.
6.Release 2 fuel hoses from fuel cooler.
CAUTION: Plug the connections.
7.Release vacuum pipe clip from fuel cooler.
8.Remove 4 bolts securing fuel cooler to inlet
manifold and remove cooler.
Refit
9.Clean fuel hose connections.
10.Position fuel cooler to inlet manifold. Apply
Loctite 242 to bolts and tighten to18 Nm (13
lbf.ft).
11.Connect fuel hoses.
12.Connect coolant hoses, secure with clips.
13.Secure vacuum hose to fuel cooler.
14.Refill cooling system.See COOLING SYSTEM,
Adjustment.
15.Fit engine acoustic cover and secure with bolts.
16.Reconnect battery negative lead.
17.Fit battery cover.
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