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Bosch Motronic M1.3 system
The Bosch Motronic fuel injection system is
designed to meet stringent emission control
legislation whilst still providing excellent
engine performance and fuel economy. The
system is under the overall control of the
Motronic M1.3 engine management system,
which also controls the ignition timing.
The principle of operation of the system is
similar to that described above for the
LE2-Jetronic system, noting the following
differences.
a) A double-barrel throttle housing is used
with two throttle valves operating
simultaneously.
b) An oxygen sensor Is fitted to the exhaust
system which allows fine mixture
adjustment to enable the use of a catalytic
converter.
c) A TDC sensor is used to provide the ECU
with information on crankshaft speed and
position.
10 Fuel injection system -
checks and adjustment
3
General information
1 If a fault appears in the fuel injection
system, first ensure that all the system wiring
connectors are securely connected and free
of corrosion. Ensure that the fault is not due to
poor maintenance; ie, check that the air
cleaner filter element is clean, the spark plugs
are in good condition and correctly gapped,
the valve clearances are correctly adjusted,
the cylinder compression pressures are
correct, the ignition timing is correct (where
adjustable), and that the engine breather
hoses are clear and undamaged, referring to
Chapters 1, 2 and 5 for further information.
2 If these checks fail to reveal the cause of
the problem, carry out the checks and
adjustments described in the following sub-
sections which represent the limit of work that
can be done without sophisticated test
equipment. If problems still exist, the vehicle
should be taken to a suitably-equipped
Peugeot dealer for testing. A wiring block
connector is incorporated in the engine
management circuit, into which a special
electronic diagnostic tester can be plugged.
The tester will locate the fault quickly and
simply, alleviating the need to test all the
system components individually, which is a
time-consuming operation that also carries a
risk of damaging the ECU.
Checks and adjustment
Idle speed and mixture CO content
3 Refer to Chapter 1.
Throttle initial position - LE2-Jetronic
system
4 Run the engine to normal operating
temperature - indicated when the electric
cooling fan has cut in and out twice. The
ignition timing must be correctly adjusted, as
described in Chapter 5B.
5 Connect a vacuum gauge to the test point
in the distributor vacuum advance line (see
illustration).
6 Check that the throttle movement is
smooth.
7 With the engine stopped turn the air screw
fully in (see illustration).
8 Prise the tamperproof cap from the throttle
stop screw (see illustration).
9 Unscrew the throttle stop screw then
retighten it until it just touches the throttle
lever. Tighten the screw a further four
complete turns.
10 Start the engine and allow it to idle. Turn
the throttle stop screw to obtain an idle speed
of 650 rpm (XU5J engines) or 600 rpm (XU5JA
and XU9JA engines). Check that the vacuum
reading shown on the gauge does not exceed
50 mm Hg (65 mbar) and if necessary adjust
the throttle stop screw.
11 Now turn the air screw in the throttle
housing as necessary to obtain the specified
idling speed.
12 Stop the engine and adjust the throttle
switch, as described below.
Throttle initial position - LU2-Jetronic
and Motronic M1.3 systems
13 The throttle initial position is set in
production, and will not normally require
adjustment unless the throttle housing has
been tampered with. Adjustment should be
entrusted to a Peugeot dealer.
Throttle switch - LE2-Jetronic system
14 Pull the connector from the throttle switch
(see illustration).
15 Connect a voltmeter between the middle
terminal on the connector and earth.
16 Pull the connector from the ignition
amplifier (see Chapter 5B), then operate the
starter motor and check that there is a reading
of at least 9 volts.
17 Disconnect the air hose from the throttle
housing.
18 On all engines except XU5JA and XU9JA,
position a 0.30 mm feeler blade between the
throttle stop screw and the throttle lever.
19 Loosen the two throttle switch screws.
20 Connect an ohmmeter between terminals
18 and 2 on the throttle switch, then rotate the
switch until the internal contacts close and the
reading is zero ohms. Tighten the screws with
the switch in this position.
21 Remove the feeler blade (where
applicable) and on all engines, insert in its
place a 0.70 mm feeler blade. The internal
contacts should now be separated and the
reading on the ohmmeter infinity. If not, repeat
the procedure in paragraph 19.
22 Remove the feeler blade.
Fuel system - multi-point fuel injection engines 4C•3
4C
10.8 Prise the tamperproof cap from the
throttle stop screw (arrowed) and adjust as
described in text
10.14 Removing the throttle switch
connector
10.5 To check the throttle initial position,
connect a vacuum gauge to the
test point (1)
10.7 Turn the air screw fully in