RENAULT MEGANE SCENIC 1995 Service Repair Manual

ANTIPOLLUTION
Oil vapour rebreathing
14
E7J engine
PRESENTATION OF THE CIRCUIT
94563R3
Upstream rebreathing circuit
1Take-off on air filter
2Filter - nozzle connecting pipe
3 6 mm diameter nozzle
Downstream rebreathing circuit
4 1.5 mm diameter nozzle
5Restriction to T union connecting pipe
6T union
7Take-off on inlet manifold
8To canister bleed
CHECKING
To guarantee correct operation of the
antipollution system, the oil vapour rebreathing
circuit should be kept clean and in good
condition.
Check the nozzles are present and correct.
14-9

99231R
ANTIPOLLUTION
Oil vapour rebreathing
14
K7M engine
PRESENTATION OF THE CIRCUIT
1Cylinder head
2Manifold
3Oil vapour rebreathing pipe connected upstream of the throttle body (the circuit is used for average and
high loads)
4Oil vapour rebreathing pipe connected downstream of the throttle body
5Fuel vapour recirculation pipe
6T piece connecting the oil vapour rebreathing pipe (4) and fuel vapour recirculation pipe (5)
7Oil vapour rebreathing pipe and fuel vapour recirculation pipe
8Air duct
95 mm diameter nozzle
CHECKING
To guarantee correct operation of the antipollution system, the oil vapour rebreathing circuit should be kept
clean and in good condition.
Check the nozzle is present and correct.
14-10

DI1407-1
ANTIPOLLUTION
Oil vapour rebreathing
14
F3R engine
PRESENTATION OF THE CIRCUIT
1Inlet manifold
2Throttle body
3Oil vapour rebreathing pipe (connected to throttle body)
4Oil decanter
5Oil vapour rebreathing pipe from the engine to the decanter
The restrictions upstream and downstream of the oil vapour rebreathing system are moulded into the
throttle body.
CHECKING
To guarantee correct operation of the antipollution system, the oil vapour rebreathing circuit should be kept
clean and in good condition.
14-11

ANTIPOLLUTION
Oil vapour rebreathing
14
F8Q engine
PRESENTATION OF THE CIRCUIT
DI1410
1Oil vapour decanter
To guarantee correct operation of the antipollution system, the oil vapour rebreathing circuit should be
kept clean and in good condition.
The oil vapour rebreathing pipes have no restrictions.
14-12

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
This system is only fitted to the K7M 703 engine.
PRESENTATION OF THE CIRCUIT
99377R
1Cylinder head
2EGR solenoid valve (operated by an RCO
signal)
3Mounting for EGR solenoid valve
4Vacuum reservoir
5Filter unit
6Inlet manifold
7Exhaust manifoldAExhaust gas to EGR solenoid valve
BExhaust gas circulation to inlet manifold
14-13

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
Mounting bolt for EGR solenoid valve 2.2
EGR solenoid valve bolt 1
Steel pipe bolts for EGR solenoid valve 1
TIGHTENING TORQUES (in daN.m)
REMOVING THE EGR SOLENOID VALVE
Remove the acoustic tie bar.
Disconnect:
- the air temperature sensor connector (1),
- the oil vapour rebreathing pipe (2).
Slacken the two clips (3) mounting the air duct (4)
and remove it.
Disconnect the accelerator cable (8).
99359R2
From the solenoid valve, disconnect:
- the vacuum pipe (5),
- the electrical connector (6).Remove the two mounting bolts for the EGR
solenoid valve, then remove the valve.
99358R1
REFITTING THE EGR SOLENOID VALVE
Renew the seal.
Refitting is then the reverse of removal.
SPECIAL NOTES
To remove the two steel pipes connecting the EGR
solenoid valve mounting to the exhaust manifold
and the inlet manifold, unclip the two clips (9) on
either side of each pipe.
14-14

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
PURPOSE OF THE EGR SYSTEM
Recirculation of exhaust gas, or EGR, is used to
reduce the nitrous oxide (NOx) content of exhaust
gas.
The formation of nitrous oxide takes place at very
high temperatures in the engine combustion
chambers when driving under heavy loads.
By reducing the temperature of the combustion
chambers, the amount of nitrous oxide produced
is reduced. The simplest means of reducing the
combustion chamber temperature is to introduce
inert gas into the chamber.
Exhaust gas is made up of used inert gasses, so it is
recirculated into the inlet manifold in the correct
amount at the right time.
SOLENOID VALVE OPERATING PRINCIPLE
The EGR solenoid valve is operated by an RCO
signal from the injection computer. The RCO
signal modulates the opening in the solenoid
valve and this permits more or less exhaust gas to
be channelled to the inlet manifold.
Depending on this signal, the solenoid valve
applies to diaphragm (A) a quantified amount of
the manifold vacuum. Diaphragm (A) moves and
pulls valve (B) which permits the passage of
exhaust gas (by vacuum) to the inlet manifold.
DI1408-1
14-15

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
OPERATING CONDITIONS FOR THE EGR SOLENOID
VALVE
The EGR system is operational if the following
conditions are met:
• coolant temperature greater than 20°C,
• air temperature greater than 5°C,
• no load position not recognised and throttle
position less than a set threshold, dependent
on engine speed (at 1024 rpm the throttle
position must be greater than 59 seen
using # 17 ;
at 5120 rpm the throttle position must be
greater than 103 seen using # 17),
• manifold vacuum greater than a certain
threshold.
The EGR solenoid valve is not operated if a fault is
detected with the :
- air temperature sensor,
- manifold pressure sensor,
- throttle potentiometer,
- EGR system.
A status bargraph on the XR25 visualises
operation of the EGR solenoid valve by the
computer.
It is however better to carry out a road test to
show this status. A test with the vehicle stationary,
engine operating under low loads is not
sufficient.
A faulty component in the EGR system will cause
an obvious worsening of the exhaust gas values.
CHECKING THE SEALING AND OPERATION OF THE
EGR SOLENOID VALVE
After the cooling fan has operated at least once,
stop the engine and turn the ignition off.
Disconnect the electrical connector.
Supply a 12 V feed directly to the solenoid valve.
Disconnect the pipe (D) connected to the vacuum
reservoir from the solenoid valve. In its place
connect a vacuum pump.
Create a vacuum of 300 mbars. The pressure
should not drop by more than 2 mbars per second
(120 mbars per minute).
Eliminate the vacuum to return the solenoid valve
to atmospheric pressure.
Run the engine at idle speed.
Create a vacuum of 300 mbars again, the engine
should run at idle speed, but unsteadily. If this is
not the case, replace the solenoid valve assembly.
Erase the computer memory after the operation.
14-16

99374R
ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
CLEANING THE EGR SOLENOID VALVE (if there is a
fault)
In certain cases, a deviation in the nitrous oxide
value at the exhaust may be noted due to the fact
that the EGR solenoid valve has become
contaminated. If this is noted, we recommend
that at approximately 50000 miles( 80 000 km),
the EGR solenoid valve is cleaned to ensure correct
depollution.
Remove as much contamination from the EGR
solenoid valve as possible then blow out with
compressed air.
Remove the two mounting bolts securing the
solenoid to the valve. Remove the solenoid
(ensure that no impurities enter the EGR valve
diaphragm area).
Remove all the pipes from the solenoid.
With no electrical feed, blow compressed air in
through union (C).
With 12 V feed, blow compressed air in through
union (B).This ensures that any possible impurities are
removed the way they entered the valve.
IMPORTANT: do not blow compressed air on the
EGR solenoid valve diaphragm.
Refit the pipes to the solenoid.
Renew:
- the O ring on union (C),
- the filter unit.
Refit the solenoid to the valve.
DI1409-1
14-17

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
F8Q engine
Depollution for this engine uses recirculation to the inlet of some of the exhaust
gasses.
Recirculation of the exhaust gas reduces the combustion temperatures to reduce the
formation of nitrous oxides (NOx).
Recirculation is only permitted under certain load and temperature conditions.
99259R
1Inlet manifold
2Exhaust manifold
3EGR valve
4Air filter
5EGR solenoid
6Microswitch (on injection pump)
7Vacuum pump
8Injection pump load lever
9Brake servo
14-18