1988 CITROEN CX engine

“LE Jetronic” system
The “LE Jetronic” is a fuel injection system whrch injects intermittently petrol, at low pressure, into the Inlet manrfold
The main characteristic of the device is to meter directly the air drawn In by the engine, which is the only reference
for the fuel quantity to be injected. The fuel metering is carried out by electro-magnetically triggered injectors. These
are under a constant fuel pressure.
The quantity of fuel injected depends on how long the injectors remain open. The duration of opening IS optimally
determined for each engine operating phase by an electronic control unit, from data supplied by various electric
sensors.
The “LE Jetronic” device is composed of:
No. COMPONENTS MADE BY REFERENCE
142 Electronic Control Unit (E.C.U.) BOSCH 0280 000 224
192 Throttle spindle switch 0
0280 120 313
280 Supplementary air control u
0280 140 178
302 Flow meter ,)
0280 202 061
345 Electrovalve ,,
0280 141 011
575 Cold start injector n
0280 170 409
576 Injector >,
0280 150 200
683 Electrical fuel
pump 1,
0580 464 008
731 Relay >,
0280 230 009
841 Coolant temperature sensor 1)
0280 130 026
870 Slow thermal switch ,>
0280 130 214
F Fuel filter ),
0450 905 002
R Pressure regulator ,)
0280 160 216

* CX @ No. 48
M25/660
- 2187 “2/87-- M25/648 M25/669 (2/87)
ROTO-DIESEL DPA MA 300 DPC MA 260 8443 A 1114 0 ROTO-DIESEL DPC MAS 100 DPC MAS 200 R 8443 A 360 A
or8361 B
ROTO-DIESEL F SL AC
0 ROTO-DIESEL F SL AC
CAV 71111796 0 CAV 71111796
ROTO-DIESEL RKB 45 SD 5422 @ ROT0 DIESEL RKB 45 SD 5422
ROTO-DIESEL RDNOSDC 6577B 0 ROTO-DIESEL RDNOSDC 6751 ROTO-DIESEL RDNOSDC 6850 C
BERU 0100 221 106
@ BERU 0100 221 106
BOSCH 0 250 200 059 BOSCH 0 250 200 059
ROTO-DIESEL R53 56 501B CO+@ ROTO-DIESEL R 53 56 502 R 53 56 503 C
Orange paint
White paint Blue paint
STATIC SETTING-2187
2187-
DYNAMIC
TIMING
IDLING SPEED
ANTI-STALL
MAXIMUM
NO LOAD
SPEED M 251660 M 25/648 M 251669
By timing marks on cylinder block and flywheel
4 12 k 0.05 mm 3.24 f 0.05 mm 3.58 t- 0.05 mm
BTDC BTDC BTDC
or 22O
or
4.71
19”
Engine hot at a speed of 800 t 25 rpm
10.30’ + 1 o
I go i 1”
800 I 25 rpm
DPA 800 t 25 rpm
DPC 800 t 50 rpm 800 & 50 rpm
4625 & 125 rpm
r
4400 + 125 rpm

CHECKING AND ADJUSTING
THE INJECTION SYSTEM
II. - INSPECTION AND TIMING OF THE “ROT0-DIESEL” INJECTION PUMP
Raise the LH side of the vehicle and support it on
stands.
Disconnect the battery negative lead.
Engage the 5th gear. Rotate the engine by turning the
wheel.
Set the No. 1 cylinder to the initial timing point,
Fig.1.
(look into the oil filter orifice).
- place cylinder No. 1 valves in the rocking position;
turn the crankshaft by one turn in the normal direc-
tion of engine rotation.
- align marks on the flywheel and on the crankcase
(++I.
- turn the crankshaft back through a quarter of a turn.
Remove either the plug (with a 32 mm ring spanner)
or the inspection plate depending on the type of the
pump.
Refit, Fig II or Ill, according to pump:
- the feeler,
- the support for the dial-gauge.
- the dial-gauge equipped with its right-angled lever.
Finding the pump internal timing point:
- turn the crankshaft in the direction of rotation until
the large pointer on the dial indicator starts moving
in the opposite direction.
- set “0” mark on the dial-gauge in line with the large
pointer.
Checking the injection pump timing:
- rotate the crankshaft by a quarter turn in the oppo-
site direction to its direction of rotation.
- turn back in the normal direction of rotation until the
“0” mark on the dial-gauge has been reached.
- in that position, marks (-1 and (c) should be in line,
Fig. I.
If not, re-check the timing. Timing the injection pump:
- set the engine to the initial trming point, Fig. I.
- turn the crankshaft by 114 turn in the opposite direc-
tion to normal direction of ro’tatron, then turn back
in the direction of rotation to bring marks t-+) and
+-I opposite.
Adjusting the pump timing, Fig. Ill:
Slacken off the injector pipe connections and the 4
attachment points.
Bring the pump to the injection point with the feeler
at the base of V-shaped groove (timing point).
Set the “0” mark on the dial opposite the needle on
the dial-gauge. Orientate the pump casing towards the
engine.
Slowly turn back to the injection point (needle facing
the “0” mark on the dial), by moving the pump
casing away from the engine (in the opposite direc-
tion to engine rotation).
Tighten the pump fixing nuts to 2.4 mdaN. During
this operation, the needle should not move.
Check the pump timing
Remove the timing tools.
Refit the plug, (tighten to 2 mdaN), or the inspec-
tion plate.
Seal the injection pump plug.
Tighten the injector pipe connections to 2 mdaN.
Reconnect the battery negative cable
Switch on the ignition (electrical STOP solenoid exci-
tation) and prime the fuel circuit using the manual
pump (5) located on the filter.
Fully depress the accelerator pedal to facilitate the
engine bleeding and start.
Note: the initial timing point corresponds to:
3.24 -L- 0.05 mm BTDC: M 25/648
4.32 + 0.05 mm BTDC: M 25/660 DPA pump
4.71 f 0.05 mm BTDC: M 25/660 DPC pump
8531

CHECKING AND ADJUSTING
THE INJECTION SYSTEM
III. - ADJUSTING THE ROTO-DIESEL INJECTION PUMP CONTROLS
DPC type pump from engine M 25/648, Fig. I
DPA type pump from engine M 25/660, Fig. II
Checking the fast-idle control
Ensure that lever (7) is against its stop, by pushing
it in the direction of arrow (-).
If not, adjust tension of cab/e by means of cable end
clamp (6). Complete tightening of cable using sheath
tensioner (41.
Checking the fast-idle control
Make sure that the cable is slack.
If not, check the operation of the thermal sensor (101
located on the water outlet duct: the cable must ope-
rate over a range of 6 mm between its “ENGINE
COLD” and “ENGINE WARM” positions.
Adjusting the accelerator control
Engine stopped:
Fully depress the accelerator pedal.
Check that lever (I) is against stop (2).
If not, move pin (3) of accelerator cable.
Make sure that, at idle, lever (I) is against stop (5).
Adjusting the anti-stalling device
Engine running:
Insert a 1.5 mm thick shim (DPC pump, Fig. I)
2 mm thick shim (DPA pump, Fig. II)
between lever (I) and stop-screw (5) at “b”.
Place a 3 mm dia. rod through the hole in lever (7)
at “a” by pushing STOP lever (9) outwards. Set the engine speed to:
800 t 50 rpm (DPC pump)
800 f 25 rpm (DPA pump)
by turning stop screw (5).
Remove the 3 mm dia. rod and the shim
Adjust the idling speed to:
800 + 25 rpm
by turning stop screw (8).
Checking the engine deceleration:
Accelerate the engine to 3.000 rpm, then release the
accelerator lever sharply.
- if the deceleration is too fast (engine often stalling),
unscrew stop-screw (5) by 114 turn,
- if the deceleration is too slow (poor engine braking),
screw up stop-screw (51 by l/4 turn.
In both cases, check the idling speed and adjust if
necessary.
If the malfunction continues to exist, carry out the
adjustments again.
Check the efficiency of the mechanically operated
STOP control (9).
Note: The setting figures are identical if the vehicle
is equipped with air-conditioning and the adjustments
are to be effected with the air-conditioning off.

Raise the R.H side of the vehicle and support it on
stands.
Disconnect the negative lead from the battery
Engage the highest gear. Using the road wheel, turn
the engine.
Set No. I cylinder to the initial timing point, Fig. I.
(look into the oil filler hole)
- Bring cylinder No. 1 valves into the rocking position
by rotating the engine one turn clockwise.
- Marks- and- should be aligned.
Remove:
- the road wheel,
- the wheelarch lining,
- the belt upper protection cover.
Loosen:
- the injection pump drrvrng pinion nut,
- the belt tensioner nut,
- compress the spring of the tensioner.
Remove:
- the pinion nut,
- the injection pump driving belt. MANDATORY: TO AVOID THE PUMP BEING
DAMAGED INTERNALLY WHEN REMOVING
THE DRIVING PINION, PULLER REF. H AND ITS
NUT J FROM TOOL BOX 6028.T MUST BE
USED.
Fit the nut and clamp of tool 6028.T, Fig. II.
Slacken the nut of tool 6028.T until the injection
pump drive shaft starts moving.
Disconnect the electrical STOP solenoid
Uncouple:
- the accelerator cable,
- the fast idling cable,
- the fuel supply pipe,
- the fuel return pipe.
DPC injection pump, Fig. ill:
Disconnect from the overfuelling circuit:
- the diesel fuel return pipe (21,
- the air pipe (I 1.
Push the diesel fuel filter to one side
Remove:
- the spring,
- the injectors sets of feed pipes,
- the pump fixing nuts (3) Fig. IV.
by means of a 73 mm A/F open spanner
and a 6 mm hexagon Allen key.

REMOVING/REFITTING D.P.A. AND D.P.C.
ROT0 DIESEL INJECTION PUMPS MA
146.1/l 5
REFITTING
Prepare
- the pump (see Op. @ MA 146.0/l/
Fit
- the pump with the mounting studs in the middle of
the slots,
- the pump fixing nuts but do not tighten home.
Assemble, Fig. I:
- the injection pump driving pinion t I); hand tighten
nut (2),
- the pump drive belt with the side opposed to the
tension roller being without slack (take care not to
rotate the pump).
Unscrew, Fig. I:
- tensioner nut (3); let the tensioner load the belt
without assistance.
Retighten, Fig. I:
- tensioner nut (3) to 2 mdaN,
- pinion nut (2) to 5 mdaN.
Carry out the pump timing:
Turn the pump towards the engine to find the point
of injection, (needle facing the “0” mark on the dial).
Screw up, Fig. II, to 2.4 mdaN,
- the pump fixing screws (4); when tightening, the dial
gauge needle should not move.
Check the pump timing (refer to @ MA 146.011)
Remove the tools
Refit:
- either the plug (tighten to 2 mdaN),
- or the inspection plate.
Seal the injection pump plug.
Refit:
- the belt upper protection cover,
- the wheelarch lining,
- the accelerator return spring,
- the injector set of feed pipes.
Tighten to 2.5 mdaN.
Recouple:
- the fast idle cable,
- the accelerator cable,
- the fuel pipe,
- the return pipe, D.P.C. pump, Fig. III.
Connect to the overfuelling circuit,
- the diesel fuel return pipe (61,
- the air pipe (5).
Put the fuel filter back into place.
Reconnect:
- the electric STOP solenoid,
- the negative cable to the battery.
Prime the fuel system using the manually operated
pump located on the filter.
Adjust the injection pump controls and idling speed
as explained in Op. @ MA 146.0/l.
8531

SPECIFICATION AND SPECIAL FEATURES
OF THE AIR SUPPLY SYSTEM
Engines types 829.A5 and J6T.A500 are fitted with a device regulating the temperature of intake air.
This device has been designed for maintaining a minimum temperature of the air drawn into the carburettor
It consists of a thermal sensor and a vacuum capsule operating a flap. Thermal source
The thermal sensor is located in the pipe connecting the air filter to the inlet manifold of the carburettor
This bi-metal type thermostat, is subjected to the inlet air temperature
It controls the opening of valves allowing passage for a depression towards the capsule
This depression is picked up by a union having a calibrated orifice, fitted to the pipe connecting the oil breather
to the intake manifold of the carburettor, and by a T-shaped union situated near the carburettor base plate, so
as to have an action over the engine load.
The thermal sensor allows the depression to circulate when the temperature is below 15°C and stops it when the
temperature exceeds 25°C. Vacuum capsule.
The capsule, located in the inlet of the air filter, is subjected to the depression. When energised, it operates a flap
which lets the heated air coming from a tapping located on the exhaust shield enter. At rest, the flap lets intake
air coming from behind the grill enter.

CHECKING THE PETROL SUPPLY
829.A5-J6T.A500
Pump AC DELCO TYPE: PB3
CHECKING THE PETROL PRESSURE WITH APPARATUS 4005-T:
- Position apparatus 4005-T.
- Disconnect the carburettor fuel return pipe; fit plug (2)
- Unscrew tap @ by one turn approx.
- Start the engine.
a) Check the petrol pressure at zero delivery:
- Fully screw up the tap; the pressure should not show a reading of more than 325 m.bar for the stabilised
pressure.
b) Check the tightness of the pump delivery valve:
- Stop the engine: there should not be a sudden drop in pressure.
c) Check the tightness of the carburettor needle valve:
- Unscrew tap @ ; start the engine, leave it running for a few minutes.
- Stop the engine: there should not be a sudden drop in pressure.
- Remove apparatus 4005-T and fit the fuel supply pipe and the fuel return pipe to the carburettor
(after plug (2) has been removed).
CHECKING THE PUMP FOR LEAKS:
Close the pump delivery tube. Blow compressed air under 800 m.bar pressure into the suction pipe. Immerse the
pump in a container filled with clean White Spirit: no leak should be detected.