1979 Citroen CX engine

Downloaded from www.Manualslib.com manuals search engine 1 - Throttle butterfly
2 - Carburettor
3 - Butterfly openinq device 4-
N PIERBURG 1) 3-way electro-valve
5 - Control relay for butterfly opening device
6 - Electronic tachometer housing 7-
(( WEBER H electro-valve 8
- Engine coolant temperature switch 9.” Relay controlling exhaust manifold air injection 10
- Choke control
11 - Air supply valve 12
- Air pump 13 -
One way valve
14 - Cylinder head
15 - Jet ( calibrated to 0.40 )

Downloaded from www.Manualslib.com manuals search engine OPERATION No MA. 142-O : Adj,,s/iaji f/a<, rarhnrt,//or Op. MA. 142.0
1
ADJUSTING THE IDLING SPEED
To carry out this adjustment, the following is needed
A tachometer
A device lor checkinq idling speed adjustments on the carburettor ( or on approved gas analyser )
- A CDA 23 checking oppmotus or a workshop test bench ( equipment mentioned in the Equipment and Repair
Materials list, or in the Tools and Equipment notes green notes )
NOTE : WEBER Carburettors ref. No W 54-50, 55-50, 69-50, 74-50 fitted on 1977 models onwards ore fitted with a
fool-proof plug ( white ) on the mixture screw. To adjust the exhaust emission, this plug has to be
removed, and
replaced, after adjustment, with a a Repair PI plug ( black ). See Op. MA, 142-000 for removing and fitting the plug,
and the necessary tools.
ADJUSTMENT CONDITIONS
1.
The idling speed adjus!ment must be carried out on an engine on which the rocker clearances and the ignition
are correctly set. with a clean air filter and
with the engine in good order.
2. Check that the butterflies return fully to their stops.
3. 30 not let pnythinq except the ignition and the engine cooling fan ( or ions ) impose any load on the alternator.
4. Run the engine to bring the
oil temperature up to 70 to 80’ C ( wait for the electric cooling fan ( or fans 1 to cut
in 1.
I. M 20/616, M 22/617, M 23/623 ENGINES I i< ?I< (5 wi/hr ,111 /or<,,,< co,1, <,r,cr or air ro,,di/io,ii?,g I ,I ‘-/
1. Wait for the electric cooling fan ( or fans ) to cut in.
2. Adjust screw (3) controlling the first choke butterfly opening until the following result is obtained : an idling
speed of 850 to 900 rpm.
3. Slowly adjust mixture screw ( 2) to obtain the following result
1.5 to 2.5 “/ of CO
1 7h~se authoris<, 8.7
% or more of CO2 nmbiot~l I~mpcuatur~ 0i 1 Y to 30” C.
4. Adjust screws (3 ) and (2 ) so that both the idling speed and the quantity of CO and CO 2 me correct.
Make sure that mixture screw (2) is adjusted last

Downloaded from www.Manualslib.com manuals search engine 2 OPERATION No MA. 142-O : A 1. Wait for the electric cooling fans to cut in
2. Engine idling speed
: Adjust screw (3) to obtain the following result idling speed of 850 to 900 rpm.
3. Slowly adjust mixture screw (2) so os to obtain the following result
1.5 to 2.5 % of CO
1 ‘, hiT<, “,, /horiscd r 8.7 ‘/ or more of co* nmhic,,/ l<~,,,pv,‘ntrr~c 0, I5 lo W” (.
4. Adjust screws (3) and (2 ) so that both the idlinq speed and the quantities of CO and CO2 are correct
Make surf that mixture screw (2) is odiusted last.
5. Fast idling speed :
Sa’itrh 012 Ihc nir rwdilim,h~g compr~~ssol: and adjust saew (4) to obtain the followinq Fast idling
speed of 1000 to 1050 rpm.
NOTE
: In case this idling speed is impossible to obtain the capsule can be moved ( by unscrewinq its two
fixihg
screws on the carburettor ) in order to reduce the clearance ot the fixing point of the rod opening the
first choke butterfly.
NOTE : On vehicles fitted with air-conditioninq the compressor must be switched off during adjustment
1. Wait for the electric cooling fans to cut in.
2. Engine idling speed
: with the gear lever in the o Neutral >) or /( Parking >a position. adjust screw (3) for the
opening of the first choke butterfly to obtain the followinq
an idling speed of 700 to 750 rpm.
3. Slowly adjust the mixture SCEW (2 ) so as to obtain
115 to 2.5 “/, of CO ‘l’h~sc anlhorisrd rcndin~ rorrc,spoad Iv m,
8.7 ‘7,
or more of CO 21 m~bt~wi I ~cnipw7tnr~~ 01 I i k, 30” (.
4. Adjust screws (3) and (2) so that both the idling speed and the quantities of CO and CO2 are correct Make
sure that mixture screw (2) is adiusted last.
5. Fast idling speed : wilh /he hnsdbmkr npplic,d, furl cz SPOT ..,gayt>d : adjust screw ! 4) to obtain the following;
fast idling speed of 725 to 775 rpm.

Downloaded from www.Manualslib.com manuals search engine OPERATION No MA. 142-O SD : (I k’ II c ,r,g m,d or/j,,r/ii,,~ /he m/i /dllllior, 5, Cl<‘,,i Op. MA. 142-O SD 1
f SIi’III)ISH \IAKKl:‘/ ,‘1,,,( 1.1’) ,
CHECKING THE SAFETY DEVICE FOR THE CHOKE i ( ?XO ,
2 1. Electrical components :
z
a Switch on the ignition
4 Pull the choke control knob the CC WEBER a) electto-valve ( 1) must be heard. If not use a test lamp to check
its electricity supply and its earthing. If the electro-valve is not supplied. check its energizinq and its
2
earthinq via the choke control.
5
;
E
; 2.P neurotic components :
?
“7
Disconnect from the air-supply valve ( 3 ) the pipe from the valve to the exhaust manifold ( 2 j
Plug the tube so as to avoid the exhaust pressure deteriorating the end of the tube and the valve
Use the starter to rotate the engine.
In this position the air-pump must not supply air through the opening in the air-supply valve previously
disconnecied.
CHECKING THE AIR INJECTION
Push bock the choke
In this position the air pump must supply air throuqh the previously disconnected opening in the air-supply
valve.
Accelerate the enqine. and suddenly decelerate
The injection of air through the openinq must stop for a short while.

Downloaded from www.Manualslib.com manuals search engine 2
OPERATION No MA. 142.0 SD : (./ )I c ,,,s m,d nd;,,s/is~~ /A? Ni/li-/Joll,lli,,ill I \/i’V, b’
/ Sll l:l~/sl1 lI.\KKI:I v1:/1/c l.JT I,
CHECKING THE IDLING SPEED AND THE CO READING I (.. JXO J
On cr vehicle fitted with the following :
-distributor : DUCELLIER 4510 B
Dwell ratio 61 7: + 3 ‘Y
Dwell angle 550 + 2”
Static advance 6”
Strobe timinq
6” at 850 rpm
Centrifuqal cuwe IA 2
- carburettor : WEBER 34 DMTR 30/200 Identification mark W 63-00
spark plugs: AC 42 FS
- engine, with the following rocker clearances : Inlet = 0.15 mm, Exhaust = 0.20 mm
Checking and adjusting the CO is carried out in the following conditions
1. Disconnect from the air-supply valve ( 3) the pipe from the valve to the exhaust manifold
2. Bring the engine oil up to a temperature of 85 ? 5’ C
3. Wait for the cooling ion ( 01
ims J to cut in.
4. Adjust screw ( 3) for opening of first choke butterfly in order to obtain on idling speed of 850 to 900 rpm
5. Slowly adjust the mixture screw (2) so (IS to obtain a CO reading of 2 to 3 “L for a temperature of 15” to 30 C
6. Adjust the mixture screw (2 ) lost
7. Connect to the air-supply valve (3 ) the pipe from the valve to the exhaust manifold.

Downloaded from www.Manualslib.com manuals search engine CHECKING THE SAFETY DEVICE FOR THE CHOKE
f (.X 2000 j :
1. Electrical components :
Disconnect the u blur )) lead feeding the thermal
switch (1) located on the water outlet duct on
the cylinder head.
Switch on the ignition.
Earth the lead from thermal switch ( 1) the relay ( 2 )
for the << WEBER 1) electro-valve ( 3) must operate.
Leave the thermal switch disconnected with the
lead insulated from earth.
Pull the
choke knob. electro-valve (3) is supplied
by relay (2 ) and is closed by earthing via the choke
control.
2. Pneumatic components :
Disconnect from the air-supply valve ( 5) the
pipe (4) from the valve to the exhaust manifold.
Plug the pipe in order to avoid the exhaust pressure
deteriorating the end of the tube and the valve
Use the starter to rotate the engine.
In this position. the air pump (6 j must
not supply
air through the previously disconnected opening in
the air supply valve ( 5)
CHECKING THE AIR INJECTION
Push back the choke
In this position. the air-pump (6 ) must supply air
through the previously disconnected opening in the
air-supply valve ( 5 1.
Accelerate the engine, and suddenly decelerate
The injection of air throuqh the opening must stop
for a short while.
Run the engine until the cooling fan ( or fans ) cut
in.
Pull the choke out : the air flow through the opening
in the air supply valve ( 5) must cease.
Push the choke in : the air flow must resume.
Connect to the air-supply valve ( 5) the pipe ( 4 )
from the valve to the exhaust manifold.

Downloaded from www.Manualslib.com manuals search engine CHECKING THE DEVICE FOR OPENING THE
BUTTERFLY
1. Electrical components :
With the engine at idling spu~d. disconnect one
of the leads to the C< PIERBURG ,) electro-valve (1).
the engine speed must increase.
If not. using a test lamp, check the following
that.
under deceleration and for any engine
speed
Nd > 1800 ? 100 rpm the /C PIERBURG >l
electro-valve (1 ) is not energized.
- that.
under acceleration and for any engine
speed from idling speed to the speed
Nc = Nd + 50 to 250 rpm. the C< PIERBURG ,,
electro-valve is energized.
If in this case the electro-valve is not energized.
ensure ( using a test lamp ) that the winding in
relay ( 2) is not enerqized for an engine speed
below ”
Nd ” ( under deceleration ) or an engine
speed below ”
NC ” ( under acceleration ).
Accelerate the engine up to engine speed ”
NC n :
- the winding in relay (2 ) must be enerqized.
If not. replace the electronic unit (3) after
having checked the connections.
2. Pneumatic components :
Ensure that the vacuum reaches capsule ( 4 1 ( device
for opening butterfly ) when the engine speed is
equal or above ”
NC “.
Make sure the vacuum exists at the carburettor
outlet. If it does. and yet does not reach cap-
sule (4) ( device for opening butterfly 1. check
the circuit along all its length. plugging it first
level with the 3-way union. on the air-supply
valve side.

Downloaded from www.Manualslib.com manuals search engine OPERATION No MA. 142-O SD : (i ‘CC ,ii:: md nr/;,,sfinji //I<, “~,ti.pOlllLliol, .S,Sl~l,, k’
c s 11’1:/~12/1 ,\lAHKli’/ “,iH,(.,.li.S , Op. MA. 142-O SD 5
ADJUSTING THE IDLING SPEED AND THE CO READING ( (.. ‘01~0 I
- IMPORTANT : II i nhsr,l,,/<~l, irirhi<&,, ,o rhnri~q~, /he sv//ing o, .Y,<,,I-r< lo,, , I , ,o, //a~ ~i.l <’ h,,,,<~r-,,,
2 I, hirh hns /,<,,‘I, “ : 0
m n (I vehicle fitted with the following :
m
-.
“, - distributor : DUCELLIER 4510 B
6
Dwell ratio 61 ‘:: ? 3 ‘,
x
2 Dwell angle
557 i 2=
Static advance 6
i
Strobe liming 6. at 850 rpm
;
F Centrifugal curve LA 2
a
a - carburettor : WEBER 34 DMTR 29/200 Identification mark W 61-00
5
“2 - spark plugs : AC 42 FS ( g.ap : 0.7 mm )
- engine with the following rocker cleoronces : Inlet 0.15 mm, Exhaust : 0.20 mm
Checking or adjusting the CO reading is carried out in the following conditions
1. Disconnect from the air-supply valve the pipe from the valve to the exhaust mariifold.
2. Bring the engine ail up to a temperature of 85” ? 5” C.
3. Wait.until the cooling fan f or fnvs 1 cut in.
4. Adjust screw ( 3) for the first choke butterfly in order to obtain on idling speed of 850 to 900 rpm
5. Slowly adjust the mixture screw (2 ) so as to obtain a CO reading of 2 to 3 “A for a temperature of 15 to 30” C
6. Adjust the mixture screw (2 1 last.
7. Adiust the throttle butterfly opening :
Disconnect one of the leads from the S( PIERBURG n electro-valve
Adjust screw (4) to obtain on engine speed of 1450 + 50 rpm
Connect the S< PIERBURG n electro-valve
8. Connect to the air-supply valve, the pipe from the valve to the exhaust manifold.