1988 CITROEN CX fuel pressure

USE OF THE MANUAL
PRESENTATION
The Repair Manual comes in a binder with a “Mu/to” type
mechanism to facilitate the filing of additive sheets
or the removal of a part for operation in the workshop.
The MECHANICAL COMPONENTS, PART 1 VOLUME (8531) covers operations on the MECHANlCAL
COMPONENTS and the BODYWORK which may be carried out by a general workshop.
It is divided into 15 chapters separated by vinyl tab inserts numbered @ to @
General
Engine
Fuel system-Carburettor
Ignition system
Clutch
Gearbox-Drive shafts
Source and reserve of pressure
Front axle Rear axle
Suspension - wheels - tyres
Steering
Braking system
Electrical equipment and radio
Heater, ventilation and air-conditioning
Bodywork
COMPOSITION OF A CHAPTER
Each chapter includes:
-
the list of operations in it,
-
the operations in numerical order.
OPERATIONS
The operation references are made up as follow: MA 100 - 00 II a
-
a) z T-r TiiTz
a) vehicle code letters: MA
b) three figure number identifying the assembly or the assembly part
c) figure indicating the type of operation:
-
the figures 000 indicate the vehicle specification
- the figures 00 indicate the assembly specification
- the figures 0 indicate checks and adjustments
- the figures 1 indicate removals and refittings
- the figures 2 indicate dismantling and re-assembly
-
the figures 3 indicate reconditioning
d) figure /I,... /2.../... standing for a variant,
e) letter: a, b, standing for an evolution
rious operations are presented:
1’ either through photos, drawings and texts,
hrough photos, drawings and symbols.
‘!%.OSSARY has been placed at the beginning of each volume for this purpose.
e glossary (the one in the Mechanical Components volume is different from the one in
caning for each symbol has been translated into nine languages.
kts in a removable set of “plastic” sheets bound with one manceuvrable me
ion of one or several pages (and obtain photocopies from them, for instance). the Bodywork volur nel,
‘tal r ing to facilitate the
85 31

“LE JETRONIC” ELECTRONIC FUEL
INJECTION SYSTEM
“LE Jetronic” system
The “LE Jetronic” IS a fuel injectiorl system which injects Intermittently petrol, at low pressure, into the inlet rnanifold
The main characteristic of the device IS to rneter drrectly 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 quantrty 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 000 300
192 Throttle spindle switch cc 0280 120 301
280 Supplementary air control (C 0280 140 172
302 Flow meter ,, 0280 202 021
345 Electrovalve ,) 0280 141 011
576 Injector n 0280 150 254
683 Electrical fuel pump
)> 0580 464 008
731 Relay D 0280 230 009
841 Water temperature sensor D 0280 130 026
F Fuel filter N 0450 905 002
R Fuel regulator pressure ,) 0280 160 216

“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

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.

CHECKING THE IGNITION SYSTEM
USING CHECKING EQUIPMENT OUT 106 029T
The instrument can be utilised on CX 2400 I.E. with naturally aspirated engine and CX 2500 I.E. TURBO. Howe-
ver, on CX 2400 I.E. having an integrated electronic ignition system with a single connector E.C.U., it is neces-
sary to proceed as follows:
- connect the I.E.I. control unit to the black connector of OUT 105 029.T
- set the switch of the apparatus to the “1 connector” position
- I.E.I. with 1 or 2 sensors can be checked with this device.
a) Testing the ignition coil primary winding:
- The warning lamps, one at each coil, blink rythmically with the impulses transmitted to their primary win-
ding. Steady blinks indicate that there is enough current to generate a spark in the secondary winding.
- The switch situated under the warning lamps makes it possible for the primary windings of both coils to
be insulated, by pushing, in the “out of circuit“ position, any interference coming from the HT circuit when
the frequency of illumination for sensor warning lamps is checked.
- If the warning lamps blinking is correct, the failure may be caused by:
- the ignition information to the fuel injection control unit, (paragraph c),
- the secondary winding (coil wires, coils),
- any other item required for a correct operation of the engine such as injection, valve gear, rockers etc.) -
If the warning lamps blinking is not correct, examine the control unit warning lamps, (paragraph b),
b) Testing the sensors: -
The warning lamp connected with the “datum” sensor blinks rythmically with the impulses transmitted by
the peg, i.e. one blink per engine revolution, (2 sensors fitted).
- The warning lamp connected with the “flywheel pick up” sensor, blinks rythmically with the impulses sent ’
by the flywheel teeth.
The frequency of the flashes is such as they can hardly be seen.
Apparently, the lamp stays on, (1 or 2 sensors fitted).
On the CX 2400 I.E. and 2500 I.E. with normally aspirated engine, the vacuum pressure warning lamp lights
up momentarily after a sharp acceleration: this warning lamp is no longer usable on the CX 2500 I.E. with
turbocharger.
c) Tests related with the I.E.I. control unit:
E.C.U. functions: -
The rev. counter warning lamp blinks rythmically with the impulses transmitted to the rev. counter.
- The injection warning lamp blinks rythmically with the impulses sent to the fuel injection control unit
+k 8531

Connectors
l.-~l
a,
- Connectors
,”
9 r, 75 Colour
FiY
E
vl
-
M
M
V
V
V
V
M
M
-
N
v
V
M
N
V
-
V
M
V
V
V
-
M
V
2
$
R
V
M
Mv
B
N
BI
B
Mv . -
z
Y
i
r”
B
G Function Function
:
m
.e-
1
-
1
2
3
-
1
2
3
4
1
2
3
4
I
2
3
4
-
1 .-
f
-
M
M
M
-
N
N
M
-
B
B
V
G
N
-
N
M
-
V
V
-
-
M 1
2
3
-
-
-
-
1
2 -
3 -
6 -
4 -
4 -
4 -
3
1
3
-
9
-
6
-
9
-
2
L.
B
-
J
-
v
-
V
-
B
m
sg
ZD
‘N
B
-
B
-
B
-
B
-
V
-
-
-
B Eng. Oil Pressure Sensor
94
95
96 Choke
Diesel Pre Heating
Front Bulb Failure 84
I 8
1
Eng. Oil Sensor
V
J
J Low Fuel Warning Lamp
Fuel Gauge
Fuel Transmitter Earth “Stop” Warning
Hydraulic Warning
Eng. Oil Low Pressure Warning
Water Low Level Warning
Water Temp. Warning
” + Ignition Switch
Battery Charge Warning
Eng. Oil Temp. Warning
Water Low Temp. Warning
2 74
80
79
77
73
80
89
70
100
102
101
98
99
97
85
90
211
212
214
103
103
9
10
11 Instrument Lighting
L/H Dir. Ind. Warning
Seat Belt Warning
+ Ignition Switch (After F2)
Earth 107
R/H Dir. Ind. Warning 105
106
85
211
108
65
66
65 BI
Mv
M
B
Mv
3
L/H Rear Door Warning
Boot Door Warning
R/H Rear Door Warning
L/H Front Door Warning
R/H Front Door Warning
Bonnet Door Warning + Ignition Switch (After F.2)
Earth
Diesel TDC
Tachometer
4
B
G Turbo Pres. Warning
Anti-knock Warning 64
63
Yelow Warning
Red Warning econoscope
5
Brake Pad Wear Warning
Hand Brake Warning
Rear Fog Lamp Warning
Side Lamp Warning
Dipped Beam Warning
Main Beam Warning
Clogged Filter Warning
0 ic 6
R Earth
Test
Warning Rear Bulb
Failure
Unit 81
82
83
7
12 ?ABS Warning
+ Ignition Switch ABS

2 MA LOCATION OF THE ELECTRONIC CONTROL
510.00/3
UNITS AND RELAYS (All Models)
POSITIONING OF THE ELECTRONIC CONTROL UNITS AND RELAYS
No. Description Location
54 ABS Control Unit G
57 Fuel Calculator Unit A
60 Air Conditioning Control Unit A
76 Window Winder Unit F
80 Speed Regulating Unit E 81
Heater Control Unit A
84 Water Level Unit L
87 Water Temperature Unit B
89 Door Locking Warning Unit A
90 Door Lock Control Unit A 91
Remote Control door Lock Unit C
92 Interior Lighting Timer A
93 Bulb Failure Indicator Unit (Salopn) H
93 Bulb Failure Indicator Unit (Safari) J 110
Heater Plug Control Unit
,. K 127
Side lamp Audible Warning D 141
Ignition ECU K 142
Injection ECU E 151
Water temperature Flasher unit B 658
Blower Speed Control Unit E 731
Fuel Injection electronic Relay M 733
Air Cond. Engine Fan Relay K 734
Injector relay M 735
Main Beam Relay D
739 Height Control relay B 743
Air Horn Compressor Relay K 745
Blower Motor Fast Speed Relay A 750
Fog Lamp Relay
6 756
ABS Electra-Valve Relay L 757
ABS Protection Relay L 772
Blower Fan Motor 2nd Speed Relay K 773
Engine Cooling Fan lnverter Relay K 775
Starter Motor Safety Relay (Auto G/Box) B 778
Fuel Heater/Starter Motor Relay (with diode) K
779 Fuel Heater Oil pressure Relay (with diode) K 781
Main fuel Heater Relay K RI
Engine Cooling Fan Relay B R2
Front Window Winder Relay 6 R3
Rear Window Winder Relay B R4
Heated Rear Screen Relay 6 I
Windscreen Wiper Timer Relay
B
C Direction Indicator Unit B

6 ARRANGEMENT OF THE ELECTRICAL INSTALLATION
CX
22 TRS 7185 --)
REF DESCRIPTION LOCATION
“;;;;;roR HARNES:
Circuit Wiring Channel-colour (or unit)
458 R/H stop lamp 105 460 L/H rear fog lamp 156 461 R/H rear fog lamp 157
462 L/H reversing lamp 27
463 R/H reversing lamp 28
470 Fuse l 480 g8 L/H front direction indicator 73 a7 30r G 481 R/H front direction indicator 76 a3 30r D 482 L/H rear direction indicator 74
483 R/H rear direction indicator 75
486 L/H long range lamp connector 159 a7 28 G 487 R/H long range lamp connector 164 a3 2B D 488 L/H headlamp 160-161 a8 3lc G
489 R/H headlamp
162-l 63 a2 3lc D 500 L/H front loudspeaker connections 139
gg IB + IR H 501 R/H front loudspeaker connections 141
gg IB + IR H 502 L/H rear loudspeaker connections 142 k9 28 PG 503 R/H rear loudspeaker connections 147 kl 28 ‘,PD 506 L/H front tweeter connections 140 h9 2B H 507 R/H front tweeter connections 140 hl 28 H
511 Rear fog lamp switch 156 to 158 g5 881 B 519 L/H window motor switch on driver’s door 85 to 87 h9 5B PC ‘520 R/H window motor switch on driver’s door 80 to 82 h9 5M PC 521 L/H window motor switch on passenger’s door 85 to 87 hl 58 PP 532 Heated rear screen switch 110 to 112 j5 5M P 545 Interior lighting switch
114 to 116 j5 58 P 570 Hazard warning switch 75 to 78
g5 8N B 580 Fuel gauge transmitter 59 to 61
96 IM 1N IJ J 600 Windscreen wiper motor 90 to 94 e4 58 D 608 Height control motor 97 to 103 j4 ‘. 38 H 615 R/H front window motor 80-81
gg 30r LV 616 L/H front window motor 85-86
gl 30R PP 621 Air intake motor 15-16 e3 2B Q 622 Air distribution motor 13-14
94 28 0 625 R/H front door lock motor 125-127
0 ZM-3B H 626 L/H front door lock motor 128 to 131 jl ZM-3B H 627 R/H rear door lock motor 125 to 127 p9 2M-3B PG 628 L/H rear door lock motor 128 to 131 pl 2M-3B PD 629 Boot door lock motor 131
t5 2B C 630 Fuel flap lock motor 127 s2 28 X 635 Engine cooling fan motor 11 a6 IM-IR V 640 Clock 32 to 34 f5 4M BA 650 Engine oil pressure switch 44 d3 IM RC 658 Blower fan speed control module 20 f3 1 V-l BI Q 680 Windscreen washer pump 95 el 2N D 690 Central interior lighting 113 to 115 n5 1N+2xllc+lM P 695 Front interior spot lamp 113 n5 lN-1M P 698 Headphone socket 143 to 146 k5 58 H 710 12 V supply soket 89 k5 IN + IM H 721 Radio connections t 12V and loudspeakers) I” + ” - &, LS) 139 to 147 k5 lR+4x2B H 727 Carburettor mixture heating element 7 IIC RM 735 Main beam relay 163-164 q7 5N T 739 Height control relay 98 to 102 f7 5N H 745 Blower motor fast speed relay 18 to 20
94 5N Q 778 Mixture element temperature relay 5 to 7 5lc RC 779 Mixture element engine running relay 8-9 5lc RC 781 Mixture element engine starting relay 6-7 5N RC 788 Engine cooling fan resistance 11 38 V 795 Lighting rheostat 62 g6 4B B 810 L/H direction indicator repeater connectrons 72 e9 II&l + IICT G 811 R/H direction indicator repeater connections 77 el II&l + IICV D 831 Interior temperature selection motor 21 to 25
cl5 5B K 836 Oil level sensor 57-58 c4 28 M 839 Interior air temperature sensor 24
j5 28 P 850
2 stage engine cooling fan thermal switch 11-12
b6 3lc V 853 Mixture element temperature thermal switch 5 IJS + IJti RM 855 Max. coolant temperature thermal switch 39 c4 IB M 935 Blower motor 19 d5 IN + li;j Q 945 Heated rear screen 111 r3 to 7 IN + IN F + ML 980 Door locked warning lamp 132
99 Ilc + Ilc H