diagram Citroen CX 1981 1.G User Guide

Downloaded from www.Manualslib.com manuals search engine DIAGRAM 3
+ Battery
:------------ ____ -----_---------- -------- -A---\,
+fi ,c
i!J &J
/---I - 0
___,’
DIAGRAM 4

Downloaded from www.Manualslib.com manuals search engine Op. MA.IE 444-O 15
3. Fuel pump feed ( with engine running ) : ( DIAGRAM 3 )
- Disconnect the E.C.U.
- Disconnect from the air-flow sensor the air hose to the butterfly housing
- Switch on the ignition:
- Actuate the air-flow sensor flap by hand’ when the petrol pump contact closes the pump should be heard
working.
If not, test the circuit using a
battery operated ohmmeter, without forgetting to test between terminal G 36 ))
on the air-flow sensor and terminal H 20 .)) on the E.C.U. for continuity ( The 2nd terminal is not connected
to the E.C.U. ).
- The resistance between terminals (( 86 b H and G 85 )) on the relay box f //j/nor thc~ I~./I. h<~ntllnr~tp ) must be
between 52 and 78 12.
P 4. Supplementary air control ( DIAGRAM 4 )
4
c
5
6
- Disconnect the E.C.U.
-E
? - Check that the supplementary air control is properly connected ( arrow on the casing )~
In
If it is fitted the wrong way round. the port may be blocked.
- The resistance between terminals (( 34 1, and (( 48 )) on the- supplementary air control must be 50 Q approx-
- Visual checking the port on the supplementary air control must be open when the engine is cold, and closed
when the engine temperature is above 60” C
- With the engine cold. if the air pipe to the supplementary air control is flattened the engine rpm must decrease.
With the engine warm, if the air pipe is disconnected, the engine must accelerate.

Downloaded from www.Manualslib.com manuals search engine 5. Air-flow sensor ( DIAGRAM 5 )
- Disconnect the E.C.U.
- Using an ohmmeter check the continuity of circuits (( 6 )a, H 7 )) (( 8 H and (( 9 )) linking the air-flow sensor to
the multiple terminal board. as well as the continuity between each of the terminals
- The air-flow meter does not require any maintenance. It is not necessary to oil the flop. It must work without
high spot or catching
When the air-flow sensor is removed blank off the ducts so OS to protect it from dust
- Check the air circuit for air-tightness.
6. Resistors and injectors :
- A dirty injector may cause o lock of power. or on unstable idling speed.
- It is possible to test the functioning of the injectors with the engine idling by disconnecting each injector
in turn the engine rpm should decrease each time.
- Disconnect the E C U
- The resistance of an injector is 2 to 3 II.
- Each supplementary resistance is 5 to 7 R
- The volume delivered by an injector ( kept constantly open and under the normal operating pressure ) is
approximately 200 cm3 /min ( 12 25 cu in/min )-
- If the rubber pipe on one of the injectors appears wet on the outside, the injector must be replaced.
- Using an ohmmeter, check the continuity of the circuits

Downloaded from www.Manualslib.com manuals search engine 2 f DIAGRAM 5
(‘
;“--“- -
I
I 1
L _____ ------- ---- J DlAGRAM 6
G----Q-.-O
O-~-C--O
r’
L-----------i

Downloaded from www.Manualslib.com manuals search engine DIAGRAM 7
r----- __ _____ ------- ---------------_
I I
I
“-7
u-j
I I I I I I I I I I I I, I, I, I, I, I I I ( “7 ’ ,-Jg rl\j ’ I I I I=1 I I I I i /
L----.-----J------ _____ --___--------I’
i3 5 DIAGRAM &
I---------- ________ - --------------------,
1
I
27
L ____ ------ ------- 2

Downloaded from www.Manualslib.com manuals search engine 7. Water temperature sensor : ( DIAGRAM 7 )
- Disconnecting ‘the water temperature sensor should cause the engine to stall. when hot.
- Disconnect the E.C U
Using the ohmmeter, test the continuity of the circuit. and measure directly the resisitance using the sensor
cc - 10’ C )) R = 7 to 12 kR
cc + 20” C )t R = 2 to 3 kQ
cc t 80” C H R -. 250 to 400 Q
e
2
ii 8. Air temperature sensor : ( DIAGRAM 8 )
E
-E
?
U-J
- Disconnect the E.C.U. -
Using an ohmmeter, test the continuity of the circuit. and measure the resistance of the sensor between
terminals (( 6 )) and (( 27 ))
(c-10’ CH. R-8toIlkQ
N t 20” C 1) R = 2 to 3 kQ
tt + 50” C n R x 750 to 900 !J

Downloaded from www.Manualslib.com manuals search engine 9. Cold-start injector, and thermal switch : ( DIAGRAM 9 )
- Disconnect the E.C.U.
- Remove the cold-start injector, and place it above a graduated container.
- Disconnect the thermal switch, and connect terminal (( 46 )) to earth
- Switch the ignition on and actuate the starter motor. the quantity delivered must be approximately
135 cm3 /min ( 8 l/4 cuin’min 1.
- Disconnect the injector: its resistance must be 4.2 Q at 20” C
- Connect the injector to the thermal switch.
- If the water temperature is below 35” C, on operating the starter motor, the cold-start injector must supply
petrol for the followinq amounts of time
- 7.5 sets for a temperature of (( - 20” C ))
-5 ” ” (( - 10“ c N
-3
” cc 0: c ))
-1 ” ” (( 20” c >)
- On operating the starter. terminal (( 4 )) of the E.C.U. terminal board must be enerqized ( voltmeter between
terminals (( 4 )) and 0 5 )) 1.
10. Switch on throttle butterfly spindle ( Idling speed function ) : ( DIAGRAM 10 )
- Disconnect the E.C.U
- Using an ohmmeter, check that there is no resistance between terminals N 2 H and (( 18 H of the multiple
connector, without touching the accelerator pedal.

Downloaded from www.Manualslib.com manuals search engine DIAGRAM 9
+ Battery DIAGRAM l-0
1
i -
er
L----.

Downloaded from www.Manualslib.com manuals search engine DIAGRAM 11
_____ -------------_--------- -------_.
‘>*
i-- _.
5!L 17. '
i'
/- . uij
-----,'
DIAGRAM 12.
-I
Air-flow sensor Switch on throttle
butterfly spindle
r----- _____ -__----------- t
Multi-stage
control, vibrator t Multiplying
stage
t m Relav
box ‘
.g Additional
2
resistors Y I
switch
Magnetically
’ I
triggered distributor Air temp Water temp sensor
sensor

Downloaded from www.Manualslib.com manuals search engine 11. Switch on throttle butterfly spindle ( maximum power function ) ( DIAGRAM 11 )
- Disconnect the E.C.U.
- Using a battery operated ohmmeter, check there is no resistance between terminals (( 3 H and (( 18 )) of the
multiple connector board, with the accelerator pedal fully depressed
t 12. E.C.U. : ( DIAGRAM 12) +
s
*
i :
2 - Visually check the condition of the terminals ( male connectors on the E-C U., and female connectors
on the multiple connector socket ).
- With the engine running, tap lightly on the E.C.U., to detect any possible defect in the soldering ( dry
joints ).