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DIESEL EQUIPMENT
Special notes
13
ALFB (solenoid controlled load dependence)
ROLE
To eliminate the action of LFB load dependence
(internal drop in pressure in the pump and
therefore advance), depending on the engine
temperature and atmospheric pressure.
OPERATION
1. Control by pre-post-heating unit
a)As long as the coolant temperature is <
29°C, the solenoid valve is fed when the
ignition is turned on.
b)If the coolant temperature sensor is faulty,
the solenoid valve is fed when the ignition
is turned on depending on the air
temperature (the air temperature sensor
is located in the pre-post-heating unit).c)If both the coolant and air temperature
sensors are faulty, the solenoid valve is fed
for 200 seconds when the ignition is
turned on.
LOCATION
Coolant temperature sensor (1) (black connector)
DI130198904R
SPECIFICATIONS
Temperature in °CResistance Ω
252 610 to 2 990
80310 to 350
Coolant temperature sensor faulty
13-18
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DIESEL EQUIPMENT
Special notes
13
2. Control by altimetric capsule
At altitude, when atmospheric pressure is
approximately 925 ± 20 mbars, the ALFB
solenoid valve is fed via a relay and the
altimetric capsule.
KEY
257Pre-heating unit
597Engine fuse box
711ALFB solenoid valve mounted on injection
pump
741Altimetric capsule
743Altimetric relayLOCATION
Altimetric capsule (741)
PRJ9925799334R
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DIESEL EQUIPMENT
Idle speed settings
13
ADJUSTING THE FAST IDLE SPEED
Set the separate idle speed lever (4) against the
fast idle screw (5), then adjust the engine speed to
950 ± 25 rpm using this screw (5).
ADJUSTING THE POSITION OF THE FAST IDLE
CABLE GRIP
(when the idle speed and residual
flow settings are correct )
Check that the separate idle speed lever (4) is
against the idle speed screw (1).
Hold the cable taut.
Position the cable grip at a distance of :
-6 mm
± 1 (without air conditioning)
from lever (4)
-2 mm ± 1 (with air conditioning)
from lever (4)
NOTE : vehicles fitted with the air conditioning
option are fitted with a fast idle control
diaphragm operated pneumatically by a solenoid
valve. Fast idle is obtained during post-heating or
when air conditioning is selected (see operating
diagram in the pre-heating section).
ADJUSTING THE DECELERATION DAMPER (6)
When the adjustments above have been made,
the deceleration damper must be adjusted as
described below.
Slacken screws (7) to release the lever (A).
Fit a 1 mm shim between the deceleration damper
and the lever (A).
Push lever (A) on the deceleration damper to the
stop.
Ensure the load lever (2) remains in contact with
the residual flow screw (3).
Tighten the screws (7) in this position.
Remove the adjusting shim and ensure there is
contact between the load lever (2) and the
residual flow screw (3).
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Page 168 of 2492
DIESEL EQUIPMENT
Microswitches
13
MicroswitchShim thickness
(mm)Microswitch
positionResistance
(Ω)
18.2closed0
19.2openinfinity
(tracks B1 and C1)EGR
17.5closed0
18.5openinfinity
(tracks B2 and C2)CA
Adjustment is made by moving the microswitch after slackening the
two mounting bolts.
1Microswitch for cutting out post-heating and
EGR
2Microswitch for cutting out air conditioning
(if operational)
99337R1
The post-heating cut-out microswitch (1) is also
used for cutting EGR .
In order to meet depollution standards this
microswitch requires precise adjustment.
Fit a shim between the anti-stall screw (residual
flow) and the load lever.
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DIESEL EQUIPMENT
Pre-post-heating unit
13
DIAGRAM KEY
104Ignition switch
163Starter
171Air conditioning clutch
206Air conditioning trifunction pressure switch
247Instrument panel
251Bi-function coolant temperature switch
257Pre-heating unit
398EGR solenoid valve
412Fast idle solenoid valve (AC version)
597Engine fuse box
642AC / pre-heating separation diode
645Passenger compartment fuse box
680Pre-heating unit n° 1
681Pre-heating unit n° 2
682Pre-heating unit n° 3
683Pre-heating unit n° 4
711Diesel fuel pump
741Altimetric capsule
743Altimetric relay
777Power feed for fuse boxConnector (A)
+ Bat+ before ignition feed
Connector (B)
1Feed to heater plugs 1 and 3
2Feed to heater plugs 2 and 4
Connector (C)
A1 / S2Load dependence solenoid valve
control
A2 / PCLoad lever microswitch information
A3 / CTNCTN type sensor coolant temperature
information
B1/+APC+ after ignition feed
B2 / DEMStarter information
B3 / TemPre-heating warning light control (via
earth)
C1 / S1Not used
C2 / -Bat Earth
C3 / ClimFast idle solenoid valve control during
post-heating phase
92206-2R
IDENTIFICATION OF CONNECTORS
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DIESEL EQUIPMENT
Pre-post-heating unit
13
LOCATION
Pre-post-heating unit (A)
This unit has two diodes to prevent the feeding of
the heater plugs when the air conditioning system
is operating and also has a CTN type air
temperature sensor.Coolant temperature sensor (1) (black connector)
99335R
BAir conditioning diaphragm control solenoid
valve on injection pump (fast idle)
CEGR control solenoid valve
98904R
SPECIFICATIONS
Temperature in °C ± 1Resistance Ω
252 610 to 2 990
80310 to 350
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DIESEL EQUIPMENT
Pre-post-heating unit
13
PRINCIPLE OF OPERATION FOR GAS PRE-POST-
HEATING
1. "Pre-heating" when the ignition is turned on
a) Variable pre-heating
The time period during which the warning
light is illuminated and the heater plugs
are fed is dependent on the coolant
temperature.3. "Post-heating" while the engine is running
Post-heating has two phases:
a) Fixed post-heating
After the engine has been started, the
plugs are for for 10 seconds.
b) Variable post-heating
Variable post-heating begins when fixed
post-heating has ended.
During this phase, the plugs are fed
alternately 1 - 3 and 2 - 4 depending on
the coolant temperature.
If the coolant temperature sensor is faulty,
the heater plugs are fed systematically for
14 seconds.
b) Fixed pre-heating
After the pre-heating warning light has
extinguished (variable pre-heating), the
plugs remain fed for up to 8 seconds
before the engine is started.
2. Starting
The plugs remain fed while the starter is
activated.If the coolant temperature sensor is faulty,
the heater plugs are fed systematically for
30 seconds.
Variable post-heating may be
interrupted:
- finally when the coolant temperature
> 65°C,
- momentarily when the unit receives
full load information (post-heating
microswitch opens) for more than 1
second ; post-heating begins again
when the engine returns to idle speed
or low load (microswitch closes).
DI1304
DI1305
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DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
1. The pre-heating warning light does not operate
TEST SOLUTION
Earth the warning light output of connector (C) using
a 2 A fuse when the ignition is turned on (track B3).
• The fuse blows.
• The warning light does not illuminate.
• The warning light does illuminate.The warning light wiring in the instrument panel is in
short circuit. Repair the wiring.
The bulb is blown or the wiring is faulty.
Replace the bulb or repair the wiring.
Check:
- + battery on connector (A),
- + after ignition on connector (C),
- battery earth on connector (C).
If the feed is correct, replace the pre-post-heating
unit.
2. The pre-heating warning light only operates for a fraction of a second when the ignition is turned on.
TEST SOLUTION
Disconnect connector (B) and test the pre-heating:
• The warning light illuminates and there is a
voltage at the connector outputs (B).
• The warning light illuminates and there is no
voltage at the connector outputs (B).
• The pre-heating warning light illuminates for a
fraction of a second only.Check the plugs circuit. If it is correct, check and
replace the faulty plug(s).
Replace the pre-post-heating unit.
Check the before ignition feed to the pre-heating
unit.
13-33