1995 RENAULT MEGANE SCENIC engine

DIESEL EQUIPMENT
Pump - timing
13
CHECKING THE PUMP TIMING
In place of the plug (1) insert the dial gauge
mounting Mot. 856 and attach a dial gauge with
socket.
99336R
Zero the dial gauge to BDC on the injection pump
piston.
Immobilise the engine using tool Mot. 1054. To do
this, turn the engine so that the camshaft sprocket
index is aligned with the timing cover reference
mark.
DI1303-1
99183R
Check the pump piston lift shown on the dial
gauge ; it should be 0.82 ± 0.04 mm. If it is not,
rotate the pump to obtain the required piston lift.
IMPORTANT : after tightening the pump
mounting bolts, turn the engine over twice.
Immobilise the engine once more to check the
pump timing.
13-27

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
13-30

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
13-32

DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
3. There is no fast idle when engine is cold (with air conditioning option)
TEST SOLUTION
Run the air conditioning.
• The fast idle operates
• The fast idle does not operate.Check the connections at the pre-post-heating unit
(connector C).
Ensure continuity between track C3 of connector (C)
and track 1 on the solenoid valve.
Replace the pre-post-heating unit (ensure the
warning light operates correctly when the ignition is
turned on).
If the fast idle solenoid valve opens the pneumatic
circuit, repair the circuit between the vacuum pump,
the solenoid valve and the diaphragm.
If the solenoid valve does not open the circuit,
measure the voltage between the 2 tracks on the
solenoid valve connector.
•12 volts
Replace the solenoid valve after testing the
connections.
•0 volt
Ensure the following continuities :
- between track 2 on the connector and earth,
- between track 1 and track C3 of the pre-post-
heating unit.
13-34

DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
4. Engine operation fault (difficulty in starting, idle speed unstable, noise...)
Check:
- the feed to the pre-post-heating unit :
•+before ignition at connector A.
•+after ignition on track B1 of connector C.
•earth on track C2 of connector C.
- at the pump connector, the resistance of the ALFB solenoid valve (between earth and track
A1) : 7Ω ± 0.5,
- the coherence of the temperature reading given by the coolant temperature sensor,
Temperature (°C) 25 80
Resistance (Ω) 2 610 to 2 990 310 to 350
- the adjustment and operation of the post-heating microswitch,
- the coherence of the open or closed status of the altimetric capsule switch according to the altimetric
pressure of the test site (the switch should be closed for a pressure > 925 ± 20 mbars).
If the fault persists carry out a complete re-adjustment of the pump.
13-35

DIESEL EQUIPMENT
Fuel filter
13
LOCATION
Principle of the electric heater
The heater has heated studs. They are ceramic,
made from barium titanate which has a positive
temperature coefficient, meaning that its
resistance increases as its temperature increases.
99332R
1Fuel filter
2Electric heater
3Hand priming unit
The electric diesel fuel heater and the thermostat
are integral in the head of the filter.
DIAGRAM
PRJ99258
449Electric heater
450Diesel heating relay
597Engine fuse box
645Passenger compartment fuse box Operating temperature
Electrical circuit closes: 0°C
Electrical circuit opens: from 8°C
Heater power: 150 W
13-37

PRJ1302
DIESEL EQUIPMENT
Inlet - exhaust manifolds
13
Manifold mounting nuts 2.5
Tightening torques (in daN.m)
REMOVAL
Vehicle on a lift, battery disconnected, remove:
- the bar between the shock absorber turrets,
-
• the air inlet pipes,
•the oil vapour rebreathing pipes,
•the EGR control pipe (if fitted),
- bolt (1) on the inlet manifold.
From under the vehicle:
Remove:
- the engine undertray,
- the exhaust downpipe.Then remove the ten mounting nuts for the
manifolds to release them.
REFITTING
Refitting is the reverse of removal.
Renew:
- the manifold gasket,
- the two exhaust downpipe gaskets.
13-40

PUMP
Brake assistance vacuum pump
13
Renew the drive dog systematically when
replacing the pump.
CHECKING
Engine warm, at 4 000 rpm, the minimum vacuum
should be 700 mbars (525 mmHg) in 3 seconds.
SPECIAL TOOLING REQUIRED
M.S. 870 Vacuum gauge
PRJ1303
F8Q engine
13-41