null  null
To prevent this. S valve is fitted inside the fuei
distributor between the primary d r w i t and the return
Sensor output voltage
tine.
I
I
Fi I&
Stoichiometric
ken
(A= 1 )
Fig. 82-15 Typical sensor output signal
dllw
Duringall modes of operation. primary circuit
pressure holds the valve dosed. However, after the
engine has been switched off the primary circuit
pressure drops and the spring baded anti-suction
valve opens to allow fuei to flow from the return fine
into the primary circuit. This prwents a depression
forming above the wntrol piston.
Acceleration enrichment switetr {see fig. 82-16)
Fined to cars with a lambda control system.
During rapid acceleration, when the engine is
cold an extra rich airtfuel mixture is requiredto
preserve good driveability and safety when overtaking.
These requirementsare fulfilled by an
acceleration enrichment switch th# is connected
electrically to the ECU (via a thermat switch mounted
in the thermostat housing) and by a vacuum hose to
the inductionmanifold.
Inside the acceleratian enrichment switch are two
electrical contacts. One of the contacts is attached to a
spring loaded diaphragmthat has a small bleed hole.
Under normal driving conditions the induction
manifold vacuum signal acts on the diaphragm,
overcomes the spring and breaks the electrical
signals.
I f the throttles areopenedquickly, the induction
manifold signat decreases rapidly. the spring returns
the diaphragm and makes the eledrieal contacts.
The electrical signal is conveyed to the ECU which
then switches to provide the necessary rich mixture.
Acceleration enrichment is no longer required
once the engine has warmed-up. Therefore, at 8
predeterminedcoolant temperature the thermal
switch contacts break to inhibit the system.
Ttrmttte position switch (see fig. 02-17)
This switch is situated on the side of the throttle body.
The primary throttle spindle activatesthe switch
and changes the fuel injection system from the 'closed
loop' operating mode when the throttle is opened
wide.
Fig. B2-16 Acceleration enrichment switch
Fig. B2-17 Throttle position switch
Warm-up regulator (seefig. 82-18)
The purpose of the warm-up regulator is to increase
the control pressure as the engine warms-up so that
at normal operatingtemperature full control pressure
is exerted on the end of the control piston.
The unit is operated by a bi-metat strip which in
cold conditions acts against the delivery velve spring
and so determines the control pressure. When the
engine is started, this bi-metal strip is electricalty
heated and releasesthe delivery valve spring which
in turn allows the spring pressure to close the fuel
passage and increasethe control pressure.
On cars fitted with a lambda control system the
warm-up regutator assembly a tso incorporates an
aneroid cell which slightly adjusts the control
pressure for mixture compensation at high altitudes.
The warm-up regulator is located so that it will
assume the temperature of the engine, this ensures
Cold start injector and themrat time switch.
Pressurecontrol valve, auxiliary air valve,
end warm-up regutator.
Eledronic c o n t r ~unit
l
and oxygen sensor.
that the mixture is not over enriched when starting a
partially warmed-up engine.
Auxiliary airv8lve (see fig. 82-19}
When the engine ismld the auxiliary air valve
supplies a larger volume of air to the ehgine than is
dictated by the position of the throttle butterflyvalve.
The air passes through a hole in a pivoted blocking
plate situated between the inlet and outlet
connections. The movement of !he blocking plate is
dependent upon an electrically heated bi-metal strip.
When starting a cold engine the blocking plate is
in the open position. Howwer, ss the bi-metal strip
warms-up it progressively relaxes its force on the
plate, allowingthe return spring to pull the plate to
the closed position. This reducesthe engine speed to
the normal idle speed setting.
Thermal t i m e e h (see fig. 82-20]
The thermal time switch limits the length of time that
the cold start injector remains open. During engine
cranking the heating coil inside the switch causes the
bi-metal contact to open which in turn, switches off
the cold start injector.
The switch is mounted in the thermostat housing
and inhibits operation of the cold start injector above
a predetermined coolant temperature.
Electrical circuit and System wsrning device
Electrical circuit [see figs. B2-21 and 32-22)
The electrical-components associated with the fuel
injection system comprise the foilowing main circuits.
Engine running sensor and fuel pump inhibit.
....
Engine runningwnser and fuel pump inhibit
(seefigs. 82-21 and 32.22)
The engine running sensor is located adjacent to the
fuel injection system electronic control unit underthe
facia.
The purpose of the engine running sensor is to
inhibit the supply of power to the fuel pump unless
the engine is running. There is however. one by-pass
to the circuit which afiowsthafuel pump to operate
when the engine is being 'cranked' by the starter
motor. A relay within the engine running sensor
assembly provides the means of switching on or off
the power supply to the fuel pump.
The supply to the fuel pump is along the pink
cabIe from the fuel injection system fuse to the
'engine running' sensor and thenouttothe pumpvia
the white/pinkcabfe. The engine running sensor circuit
is fed via the ignition fuse and h e white cable. It is
earthed through the black cable. When the engine is
beingcranked, a 12volt feed on the brownlblackcable
causes the retay in the sensor to be 'pulled in' and
thusthefuel pump is switched on. Oncethe engine is
running the ignition pulses from the coil primary are
fed to the engine running sensor through the white1
black wire and the pump -relay remains energized.
If the engine speed falls below 150 revlminthe
time between the ignition pulses is too long to hold
the relay in the energized state and therefore, the
power to the fuel pump is switched
..: . ,
off. _ .!
Diagram A
fig. 32-18 Warm-up regulator
1 Bi-metal strip with heater elements
"
2187
2 Vent to atmosphere
3 Diaphragm
4 Return spring
5 Aneroid cell
Fuel inlet connection
Fuel outlet connection
Bleed orifice
A Coldengine
3 Warm engine
6
7
8
TSD 4737
T
2
3
Cold start injdetor and ?hrmal time switch
(see figs 82-21 and 82-22)
When theengine is being 'cranked' {i.e. the key in the
4
switchbox is held in the START position} power w l l
be supplied via the whiielred cable from the starter
retay to the thermal rime switch, situated in the
thermostat housing and the cold start injector. The
injector will therefore, operate whenever the engine
is being 'cranked', unless the earth is interrupted by
the thermal timeswitch due to eitherthetemperature
of engine coolant or the Length of operating time.
Diagram A
Fig. 82-19
'I
2
3
4
5
6
7
8
9
10
11
A
B
Diagram
- B
Auxiliary air valve
Blocking plate
Airnow direction
Upstream throttle connection
Heating coil
Bi-metatlic strip
Clamping pin
Blocking plate limit stop
Return spring
Pivot. pin
... . .
. ....
Heatingcoil conhition block
Downstreamthrottle connection
Cold engine
Warm engine
Fig. B2-20 T h m a l time switch
1 Thermostat housing
2 Housing
3 Heating eoil(s)
4 Plug connector
5 Bi-metalliestrip
6 Contacts
W
Sptem warning device (see fig. 82-22]
fitted to cars with a lambda control system (except
cars produced to the Japanese specification).
Failure of the oxygen sensor is detected by the
electronic control unit which relies upon the output of
thesensor for 'closed loop control'. Fsilure will cause
thesystem to change to the 'open loop control' and in
addition, illuminatethe warning lamp bulb on the
facia to indicate the need for maintenance,
The warning iamp may illuminate when the
engine is being cranked but should extinguish soon
after the engine starts. The lamp will however, remain
illuminateduntil theoxygen sensor reaches it
normal operating temperature.
Modes of operation
Engine warm-up
During the warm-up period two basic compensations
are necessary.
The first compensation is for fuel condensation
losses on the cold wails of the combustion chamber
andinlet manifold. The second compensation is for
powzr lost due to increased mechanical friction.
The compensation for condensationlosses is
achieved by increasingthe fuel flow to the injectors.
The power fost is overcome by feeding a larger
volume of air into the engine than is dictated by the
position of the throttte butterflies.
Prior to the engine starting the coptrol piston is in
its fowest position. However, once the air sensor plate
is moved downwards by the force of the intake air,
the control piston will be moved upwards in the barrel
of the fuel distributor.
The control piston is aflowedto move further up
the barrel of the distributor (for a given volume of
intake air), because the control pressure acting
against the upward movement of the piston, has been
reduced by the action of the warm-up regulator.
The extra movement of the control piston
increases the opening at the fuel metering slits and
atfows more fuel to flow to the injectors.
As the bi-metals in the warm-up regulatorand
the auxiliary air valve are heated they alter the
characteristicsof their respective components.The
warm-up regulator gradually closes the return line to
the fuel tank which therefore, increases control
pressure and restrictsthe movement of the control
piston in the fuel distributor. This action limitsthe
opening of the fuel metering slits, reduces the fuel
flowing to the injectors, and weakens the mixture.
The bi-metal of the auxiliary air valve
progressively relaxes its force on the blocking plate,
allowing the return spring to pull the plate to its closed
position. This reduces the engine idling speed to its
normal seiting.
Engine idle speed
When the engine attains normal operating
temperature it will adopt its normal idle speed. This is
initially set during the manufacture of the vehicle by
adjusting screws that act directly on the throttle
mechanism. The screws are then made tamperproof
to prevent further adjustment.
After the engine has settled or 'run-in' minor
corrections to the idle speed setting can be achieved
by bleeding air around the throttle butterflies, using
the bleed screw situated on the side of the throttle
body. This bleed screw has a limited range of
adjustment.
The idle mixture is controlled by an adjusting
screw which aas directly onto the air sensor plate
lever, altering its position relative to the control
piston. Turning the screw will either raise or lower the
control piston for a given idle speed position of the air
sensor plate, this wilt either richen or weaken the idle
mixture.
Note The idie mixture is pre-set at the factory and
sealed. No further adjustment shoutd be
necessary.
When the transmission selector is moved from
the neutral position, the additional load of the
transmission would normally reduce the idle speed.
This is overcome by the idle speed control solenoid.
1his solenoid allows sir to by-pass the throttle plates,
thereby restoring the idie speed t o the optimum
setting.
Engine part load operation
As the engine speed and toad are increased the air
Fig. 82-21 Theoretical wiring diagram (cars not fitted with a
1 Fuel injection system fuse
9
2 Ignition, starter, and fuel pump fuse
10
3 To alternator
1l
4 Engine running sensor
12
5 From starter relay
13
6 From ignition coil
14
7 From starter
15
8 Thermal time switch
'16
10187
catalytic converter)
Cold start injector
Fuel pump
Fusl pre-pump
Throttle position switch
Kick-down solenoid
Heaters inhibit relay
Warm-up regulator
Auxiliary air valve
TSD 4737
sensor plate is progressivelyforced downwards by
the increased Bow of intake air.
The downward movement of the sensor plate is
transmitted via the sensor lever, to the control piston.
The control piston is raised accordingly in the barrel
of the het distributor, ellowing additional fuel.to pass
through the metering slits.
The diaphragm in each of the differential pressure
valves responds to this additional fuel flow by
deflecting funher away from the injection line outlet.
This allows more fuel to flow to the injectors.
Engine full load operation
Under full load conditions the air sensor plate exhibits
maximum deflection and the control piston is at its
highest position in the barrel of the fuel distributor.
This gives the largest openings of the metering sHts.
The diaphragm in each differential pressure valve
isdeflectedto its furthest point away from the outlet
tube to the injectors. allowing maximum fuel flow.
Due to the action of a throttle position switch
actuated by the primary throttle spindle. the electronic
control unit changes t o the internal mode. thus
Fig. B2-22Theoretical wiring diagram (ears fitted with a catalytic converter)
K e y to fig B 2 - U Theoretical wiring diagram
(cam fmed with a catalytic convaer)
instruments and warning lamps fuse
Fuel injection system fuse
Ignition, starter, and fuel pump fuse
To alternator
5 fngine running sensor
6 From starter relay
7 From ignition coil
8 From starter
9 Thermal time switch
10 Cold start injector
11 Fuel pump
12 Fuel pre-pump
13 . Pressure control vafve
14 Heaters inhibit relay
t 5 Warm-up regulator
'16 - Auxiliary air va tve
17 Oxygen sensor and heater
18 Kick-down relay
19 Acceleration enrichment temperature switch
20 Acceleration enrichment Switch
21 Fuel injection electronic control unit
22 Kick-down solenoid
23 Throttle position switch
24 Oxygen sensor warning [amp (other than
Japan1
25 Test connection
26 Emission control temperature switch
27 Exhaust gas recirculation solenoid
28 Air diverter valve
29 Evaporative loss control solenoid
1
2
%
4
blocking the 'closed loop' system and providing
additional enrichment by modifying the fixed signal
to the pressure control valve.
Workshop safety precautions
General
Always ensure that the vehicle parking brake is firmly
applied, the gear range selector lever is in the park
position and the gearbox isolator fuse is removed from
the fuseboard.
A number of the nuts, bolts, and setscrews usad in
the fuel injection system are dimensioned to the metric
system. it is important therefore. that when new parts
become necessary the correct replacements are
obtained and fitted.
Fire
-Fuel is highly flammable. therefore great care must be
exercised whenever the fuel system is opened (i.e.
pipes or unions disturbed) or the fuel is drained. Always
ensure that 'no smoking' signs and foam, dry powder,
or CO, (carbondioxide)fire extinguishers are placed in
the vicinity of the vehicle:
Always ensure that the battery is disconnected
before opening any fuel lines. .
If the fuel is to be drained from the tank, ensure
that it is siphoned into a suitable covered container.
Fuel prwaum
The fuel inj9dion system contains fuel that may be
under high pressure approximatdy 5.2 bar to 5.8-bar
175.4 Ibf/inZto84.1 Ibflinyl.Therefore, to reducethe risk
of possible injury and fire, always ensure that the . system is depressurizedby one of the following,
methods before commencing any work that will entail
opening the system.
1. Clean the inlet connectionto the fuel filter. Wrap
..
an absorbent cloth around the joint and carefully
slacken the pipe nut to release any pressurized fuel
from the system. Tghten the pipe nut.
2. Allow the pressure to fall naturally by switching off
the engine 8nd allowing the vehicle to stand for four
hours before opening the system.
Health risk
Fuel may contain up to 5% of benzene as an anti-knock
additive. Benzene is extremely injurious to health
[being carcinogenic1therefore, all contact should be!
kept to an absolute minimum. particularly inhalation.
Fuel has a sufficient high vapour pressure to allow
a hazardous build-up of vapour in poorly ventilated
areas. Fuel vapour is an irritant to the eyes and lungs, if
high concentrations are inhaled it may cause nausea,
headache, and depression. Liquidfuel is an irritant to
the eyes and skin and may cause dermatitis following
prolonged or repeated contact.
When it becomes necessary to carry out work.
involving the risk of contact with fuel, particulariy for
prolonged periods, it is advisable to wear protective
clothing including safety goggles. gloves, and aprons.
Any work should be carried out in e well ventilated
area.
If there is contact with f u l the following
emergency treatment is [email protected],.
Ingestion (swallowing)
Do not induce vomiting. Give the patient milk to drink
(if none is available water can be given). The main
hazard after swallowing fuel is that some of the liquid
may get into the lungs. Send the patient to hospital
immediately.
Eyes
Wash with a good suppfy of clean water for at least l 0
minutes.
-
Skin contact
Immediately drench the effected parts of the skin with
water. Remove contaminated clothing and then wash
all contaminatedskin with soap and water.
Inhalation(breathing in vapour)
Move the patient into the fresh air. Keep the patient.
warm and at rest. If there is loss of consciousness give
artificial respiration. Send the patient to hospital.
Cleanliness
.
tt is eKtremely important to ensure maximum
cleanliness whenever work is carried out on the system.
f he fol towing points should always be observed.
Engine does not $tan. or starts m r l y from cold
1 -
IH I i
-
-
1
Irregular ~dlewhen warm
I
Engine will not accelerate
I
Engine misfires when operating under high load
I
Insufficient power
-
Engine 'runs on' after being switched off
Excessive fuel consumption
Flat spot dur~ngacceterat~on
CO concentration too high (open loop 1
1
CO concentration too low (open loop 1
Idle speed too high
Idle speed roo low
Engine swns but immediately stops
Possible cause
Refer to
workshop
procedure
1
2
plate
Incorrect operation of the auxil~ary
air valve
3
4
5
6
7
8
Unequal fuel d e l i v e ~from distributor 9
Incorrect idle speed adjustment
10
Incorrect idle rnlxture strength
11
faulty lnjectors
13
14
15
16
Fuel accumutator diaphragm burst
Incorrect operation of idle by-pass
solenoid
17
Pressure control valve damper failure 18
Faulty accelerat~onenrichment switch 19
Fautty exhaust gas recirculat~on
systernrefer to Chapter F
Faulty 'closed loop' system - see appropriate flow chan
-
Workshop procedures 1 to 17 inclusive apply to all cars. A combination of the remainder also apply to cars
produced to an Australian, Japanese, or North America specification.
Fig. 62-23 Basic K-Jetronic fault diagnosis chart
I
Engine does not start or srarrs poorly when warm
Irregular idle during warmup
I
l
-
'Closed loop' system fault diagnosis chart
Sheet 1 of 2
lotat.'
TSD 4737
h lrnportrnt
Before commencing work run the engine for three minutes. switch off the ignition and allow to d.
Ensurb ttla
1. The test meter is connrad(see illustrations)
2. The stemr relay has been removed
3. The alectrkal feed to the cold start iniector has been disconnected
4. The ignition is switched on
Hold tha ignition kmy In the crank position far aH the following operations
Check the supply to the electronic cantrol
Cen the vibration of the pressure control
valve be heard,
YES
L
Ooas the pressure cmtml valve now work?
N0
F-
h
Test meter reads 45% to 55%
l
J
YI
l
C
Disconnect the ox-get
that the meter rtil: tea
Connect green s e r ~
commf unit to earth f
to 88% minimum of t
P
I
+( a 55%
P
Pressure control vake electrically defective
l
wntrol valve is between 2 and 3 ohms.
(
) pnssun contro!
Chock thl electrical pzg to the m m 1 valve.
One contmcl is a 12v supply. One wntect is
fauhy
J
to electronic wntrol unit pin 1 5 (Check for
continuity] is this test satisfactory?
8A-- '
-
Electronic contro\ unit taulty
A
Disconnect the oxygen sensor. Test meter
reads 45% to 55%
~nections.Test meter
II
ensor cable. Ensure
45% 10 55%.
ble from electronic
I meter rises slowly
limit
Y
NO
lY€sl
Check for eontinu'hy of cable from electronic
eontrol unit pin 2 to owygen sensw
Electronic control unit iauhy
Y
Faulty wiring loom or contacts
l
-
'Closed loop' system fault diag,nosischart
Sheet 2 of 2
r
,,
1
1
Continued from .heel l
;:;
Furly depress the accelerator pedal. Tes:
meter reads 60% to 70%
switch is set
-2th,o
Reset the
YES
W~ththrottles fully open. Check for cable
continuity from electronic control unit pin 7
to vehicle earth
YES
With the oxygen sensor cable still
disconnected, connect a CO anslyler into the
exhaust pipe sample tapping. Run the engine
until normal operating temperature is
attained. Cheek that the idle CO is between
0.5% and 0.7% at 580 rev/min in park
Carw out tests to basic K-Jatronic fuel
ll
YES
Disconnect ths
Is thm CO volue unchanged?
I
Cheek the engine idle speed and adjust if
necessary
regutat and in
I Y
Cheek for exhaust gas-leaks et the erhnust
manifolds and oxygen sensor
I
Oxygen m m
I
I t position switch
oxygen secisw cable
)s idle spwd become
:raasa?
5
faulty
Pressure cllntrol valve has failed mechanically
I
l. To prevent the ingress of dirt. always clean the
area around a connection before dismantling a joint.
2. Having disconnected 3 joint (either fuel or air!
always blank off any open connections as soon as
possible.
3. Any components that require cleaning should be
washed i n clean fuel and dried, using compressed air.
4. If it is necessary to use a cloth when working on
the system, ensurethat it is lint-free.
Fault diagnosis
f his fault diagnosis section includes.
Basic system test procedure.
Electrical and Elearonic components fault diagnosis.
Mechanical components fault diagnosis.
It is important that fault finding is carried out in the
sequence given. Electrical and electronic faults can
exhibit symptoms similar to mechanical faults.
Therefore an incorrect diagnosis may be made which
could result in both lengthy and costly repairs.
Often, a mechanical f a ~ ~has
t t sufficiently well
defined symptoms to enable a very rapid diagnosis t o
be made.
f he basic fauk finding procedure is as follows.
noting that any faults found in one system should be
rectified before moving on to the next slage of the
procedure.
1. Carry out a compression test o n the engine
cylinders {to inhibit the operation ofthe system during
this test, remove the fuel injection fuse).
2. Check that the ignition system is operating
satisfactorily (refer to Chapter E).
3. Ensure that the vacuum system is free from leaks
(see fig. 82-23].
4. Ensure that the E.G.R. system is free from leaks
(refer to Chapter: F].
5. Ensure that alf auxiliary air hoses and crankcase
breather system hoses are free from leaks.
6. Check that the solenoid valves and their thermal
switches are working correctly.
7. Test the basic KJetmnic system for correct
operation (see fig. 02-231.
8. Test the 'closed loop' system for correct operation
(refer to Fault diagnosis flow chart).
Note Procedures 1.2. 3.5, and 7 apply to all cars. In
addition, a combination of procedures 4. 6, and
8 also applv to cars produced to an Australian,
Japanese. or North American specification.
Before commencing any fault diagnosis or work
on the fuel injection system ensure that the workshop
safety precautions are fully understood.
During manufacture, the components of the fuel
injection system are precisely adjusted in orderto
comply with the relevant emission control regulations.
Therefore, alterations to any of the settings should not
normally be necessary.
-
Diagnosing and correcting faults
The workshop procedure number refers to the fault
diagnosis chart for the basic K-Jetronic system given in
figure B2-23.
-
Before ~arryingout any tests. ensure thrtthe
battery is ina fully charged condition.
It should be noted that all components of the
system (except the injectors) can be tested on the
vehicle.
Procedure 1 Induction system sir leaks
Visually check all vacuum hoses. pipes, and clips for
damage o r looseness that may allow an air leak into
the induction system.
Check the entire induction system for air leaks with
the engine running. Use a suitable length of rubber
hose as a listening aid. The leak will ofken be heard as a
high pitched hiss or whistle. '.
P r o d u n 2 Metering control unit lever sticking
1. Ensure that the engine temperature is above 2WC
(68°F).
2. Remove the air intake elbow from the inlet t o the
control unit.
3. Apply control pressuret o the control piston in the
fuel distributor for approximately 10 seconds (refer t o
page 82-32}.
4. Press the air sensor plate slowly downwards t o its
maximl~mopen position. The resislance to this
movement should be uniform over Ihe whole range of
travel. Allow the air sensor plate t o return to its rest
position and repeat the operation.
If the resistance t o the air sensor plate movement
is uniform over the whole range of travel, the metering
unit is not sticking.
Note Whenever the airflow sensor plate is depressed
fuel wilt be sprayed into the engine. Therefore,
the sensor plate should only be depressed the
minimum number of t i f i s t o carry out this
operation.
5. Should the resistance t o air sensor plate movemenr
be greater in the rest position, i t could be due to the
plate being eitherout of position or bent.
6. Ifthe conditiondescribed in Operation 5 is
confirmed, depressurize the fuel system (refer to
Page 32-15). Then, press the plate fully downwards a r ~ d
allow it to spring back to the rest position. It should
return freely and bounce downwards slightly from the
spring loaded stop at leasl once.
7. Should a resistance be confirmed in Operation 6.
remove the air sensor plate end repeat the operation, If
this alleviates the resistance, the air sensor plate is
fouling the sides of the air funnel and should be
centralized (refer to Procedure 3) or the air funnel may
be deformed.
8. If there is still a resistance t o the movement of the
lever, it could be due to contamination within the fuel
distributor barrel or occasional binding in the lever
mechanism.
9. Contamination within the fuel distributor can be
checked by separating the fuel distributor from the
control unit and withdrawing the control piston for
inspect ion.
Remove the screws situated on top of the fuel
distributor. Lift off the fuel distributor (resistance will
be felt due t o the rubber sealing ring), bend back the
,,h*.
piston retaining tabs end withdraw the piston.
Handle the oontrol piston with careto ensure that
it doso not become damaged.
Do not handlethe control piston on its working
surfaces.
10. Thoroughly clean the control piston in clean fuel.
l3. Fit the control piston to the fuel distributor. Ensure
that the spring is fitted above the piston.
Bend the retaining tabs so that the piston cannot
fall out. Ensure that the rubber sealing ring sifuated
between the fuel distributor and the mixture control
unit is in good condition. lubricate the rubber sealing
ring with suitable grease and fit the distributor,
Fig. 82-25 Checking the height.ofthe.airftow.sensor
plate
A
0.5 m m (0.020 in)
ensuring that the remining screws are evenly tightened.
If a resistance is stitl noticeable, a new fuel
distributor assembly should be fitted to the mixture
control Unit.
12. After fitting the fuel distributor check the idle
mixture strength.
Procedure 3 Positianingthe air flow sensor plate
1. Remove the air inlet elbow from above the air
sensor plate.
2. Check that the sensor plate is flat and that it will
pass through the narrowest part of the air funnel
without fouling.
3. tf necessary, loosen the plate securing screw.
4. Insert the guide ring RH 9609 whilst retaining the
sensor plate in the zero movement position. f his will
prevent the sensor plate from being forced downwards
as the centring guide ring is being installed.
5. With the centring guide ring in position, tighten the
retaining screw. Carefully remove the centring guide
ring.
6. Apply control pressure to the control piston in the
fuel distributor for approximately 10 seconds (refer to
page 82-32].
7. The upper edge of the sensor plate adjacent to the
fuel distributor, should be flush with the beginning of
the upper cone as shown in figure 82-25.
Note It is permissibleto leave the top edge of the air
sensor plate protruding into the upper cone by a
maximum of 0.5 mm (0.020 in). The lower edge
of the plate (which is chanifered) must not
project upwards outside the short cylindrical
part of the air funnel, at any point on its
circumference.
8. If the air sensor plate is positioned too high,
remove the fuel distributor and carefully tap theguide
pin lower using a mandrel and a small hammer {see
fig. 82-26].
Note This adjustment must be made very carefully,
ensuring that the guide pin is not driven too lowRepeated adjustment can loosen the guide pin.
Serious damage to the engine could result i f the
pin should fall out.
Procedure4 Checking the operation of the auxiliary air
valve
1. Ensure that the engine is cold.
Fig. B2-26 Height adjustment for the air flow sensor
plate
2. Disconnect the elenrical plug at the auxiliary air
valve.
3. Discannecttheinlet and outlet rubber hoses from
the auxiliary air valve.
4. Using a flashlight and mirror, observe the position
of the hole in the blocking plale {see fig. B2-27). It
should be partially uncovered. If the blocking plate
completely closes the air passage, fit a new auxiliary
air valve.
5. If the air passage way is open, connect the
electrical plug to the auxiliary air valve.
6, Apply electrical power to the heater in the auxiliary
air valve (refer to page 02-33).
7. The air passage through the valve should be
completely closed within four 10 five minutes.
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