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4B
Chapter 4 Part B:
Fuel system - single-point fuel injection engines
General
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear-mounted fuel tank, electric fuel pump, single-point fuel injection
system
System application:
TU1M/Z, TU3M/Z and TU3FM/L engines. . . . . . . . . . . . . . . . . . . . . . Bosch Mono-Jetronic A2.2
XU5M2/Z engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMFD Mono-point G5
TU1M/L, XU5M3/Z and XU5M3/L engines . . . . . . . . . . . . . . . . . . . . . MMFD Mono-point G6
Fuel system data
Idling speed* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 ± 50 rpm
Idle mixture CO content* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Less than 1.0 %
*Not adjustable, controlled by ECU - data given for reference purposes only
Recommended fuel
Minimum octane rating (see text Section 8) . . . . . . . . . . . . . . . . . . . . . . 95 RON unleaded. Leaded fuel must not be used
Air cleaner assembly - removal and refitting . . . . . . . . . . . . . . . . . . . 2
Air cleaner element renewal . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Fuel gauge sender unit - removal and refitting . . . . . . . . . . . . . . . . . 6
Fuel injection system - testing and adjustment . . . . . . . . . . . . . . . . . 10
Fuel injection systems - general information . . . . . . . . . . . . . . . . . . . 9
Fuel pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Fuel system - depressurisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fuel tank - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
General fuel system checks . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
General information and precautions . . . . . . . . . . . . . . . . . . . . . . . . 1
Inlet manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 13
MMFD Mono-point G5 and G6 system components - removal . . . .
and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Mono-Jetronic A2.2 system components - removal and refitting . . . 11
Throttle cable - removal, refitting and adjustment . . . . . . . . . . . . . . . 3
Underbody and fuel/brake line check . . . . . . . . . . . . . . .See Chapter 1
Underbonnet check for fluid leaks and hose condition . .See Chapter 1
Unleaded petrol - general information and usage . . . . . . . . . . . . . . . 8
4B•1
Specifications
Contents
Easy, suitable for
novice with little
experience
Fairly easy, suitable
for beginner with
some experience
Fairly difficult,
suitable for competent
DIY mechanic
Difficult, suitable for
experienced DIY
mechanic
Very difficult,
suitable for expert DIY
or professional
Degrees of difficulty
5
4
3
2
1
1 General information and
precautions
General information
The fuel system consists of a fuel tank
(which is mounted under the rear of the car,
with an electric fuel pump immersed in it), a
fuel filter, fuel feed and return lines, and the
throttle body assembly (which incorporates
the single fuel injector and the fuel pressure
regulator). In addition, there is an Electronic
Control Unit (ECU) and various sensors,
electrical components and related wiring. The
air cleaner contains a disposable paper filter
element, and incorporates a flap valve air
temperature control system. This allows cold
air from the outside of the car and warm air
from around the exhaust manifold to enter the
air cleaner in the correct proportions.
Refer to Section 9 for further information on
the operation of each fuel injection system.
Precautions
Warning: Petrol is extremely
flammable - great care must be
taken when working on any part
of the fuel system. Do not smoke
or allow any naked flames or uncovered
light bulbs near the work area. Note that
gas powered domestic appliances with pilot
flames, such as heaters, boilers and tumble
dryers, also present a fire hazard - bear this
in mind if you are working in an area where
such appliances are present. Always keep a
suitable fire extinguisher close to the work
area and familiarise yourself with its
operation before starting work. Wear eye
protection when working on fuel systems
and wash off any fuel spilt on bare skin
immediately with soap and water. Note that
fuel vapour is just as dangerous as liquid
fuel; a vessel that has just been emptied of
liquid fuel will still contain vapour and can
be potentially explosive. Petrol is a highly
dangerous and volatile liquid, and the
precautions necessary when handling it
cannot be overstressed.
Many of the operations described in this
Chapter involve the disconnection of fuel
lines, which may cause an amount of fuel
spillage. Before commencing work, refer to
the above Warning and the information in
“Safety first” at the beginning of this
manual.
When working with fuel system
components, pay particular attention to
cleanliness - dirt entering the fuel system
may cause blockages which will lead to
poor running.
Note: Residual pressure will remain in the
fuel lines long after the vehicle was last used.
When disconnecting any fuel line, first
depressurise the fuel system as described in
Section 4.