RENAULT MEGANE SCENIC 1995 Service Repair Manual

ANTIPOLLUTION
Catalytic converter
14
To meet the requirements of the EURO 96
standard, this vehicle is fitted with an oxidation
catalytic converter.
ROLE
The converter deals with the following three
pollutants at the same time:
- hydrocarbons (HC),
- carbon monoxide (CO),
- particulates, by a chemical oxidation reaction.
FUEL
No specific fuel is required for correct operation.
CONSTITUTION
The converter comprises:
- a monolith (1) in a honeycomb ceramic. A
substance containing precious metals is
deposited on the walls of the honeycomb
(mainly platinum),
- a metal jacket (2) retaining the monolith in its
shell,
- a shell (3) with inlet and outlet cones,
optimising the distribution of exhaust gas
flow.
99781R
CHECKING THE CATALYTIC CONVERTER
The performance of the catalytic converter on the
exhaust gas is difficult to check. The maximum
temperature of the exhaust gas from a diesel
engine is not sufficient to melt the monolith (in
comparison to petrol engines).
Diesel engine
14-19

ANTIPOLLUTION
Catalytic converter
14
FAULT FINDING
Faults which may cause a customer complaint due
to the catalytic converter.
1. Catalytic converter polluted by an
accumulation of soot, causing poor efficiency
of the converter.
Cause :
- prolonged town driving,
- air filter dirty,
- poor operation of the EGR system
- injection pump fault, etc.
Customer complaint:
- lack of power,
- large amount of smoke.
Solution:
De-contamination of the exhaust pipe by hard
driving on open roads.
2. Loss of efficiency due to premature aging of
the monolith*
Cause :
- injection incorrectly set,
- oil vapour rebreathing fault, etc.
Customer complaint:
Abnormal engine operation.
Solution:
Replace the catalytic converter.
(*) By prolonged operation at exhaust gas
temperatures which are too high (greater
than 800°C). Diesel engine
14-20

ANTIPOLLUTION
Catalytic converter - oxygen sensor
14
CHECKS TO BE MADE BEFORE THE ANTI-
POLLUTION TEST
Ensure:
- the ignition system is operating correctly
(correct spark plugs, correctly set plug gap,
high voltage leads in good condition and
correctly connected).
- the injection system is operating correctly
(supply is correct - check using the XR25).
- the exhaust pipe is correct and is sealed.
- the EGR is operating correctly.
Check the vehicle history if possible (run out of
fuel, lack of power, use of incorrect fuel).
CHECKING ANTI-POLLUTION STANDARDS
Run the engine until the engine cooling fan has
operated twice.
Connect a correctly calibrated four gas analyser to
the exhaust tail pipe.
Keep the engine speed at 2500 rpm for
approximately 30 seconds then let the engine
return to idle speed and note the pollutant values.
CO
≤0.3 %
CO
2≥14.5 %
HC
≤100 ppm
0,97
≤λ≤1.03
1
NOTE : λ = ————
richness
λ>1→lean mixture
λ<1→rich mixture
If, after these tests, the values are correct, the
antipollution system is correct.
If the values are not correct, additional tests must
be carried out:
- Check the condition of the engine (condition
of the oil, valve clearances, timing, etc,...),
- Check the correct operation of the oxygen
sensor (see section 17) ,
- test for the presence of lead (see following
page).
If the test for the presence of lead is positive, en-
sure the vehicle uses two or three full tanks of un-
leaded fuel before replacing the oxygen sensor.
If, after all these tests have been carried out, the
values still do not conform, the catalytic converter
must be replaced. Petrol engine
14-21

93703S
This test is only possible using the Nauder lead test kit.
To obtain a test kit, contact your After Sales Head Office.
Part numbers: - For the complete kit: T900
- For a set of 40 test papers : T 900/1
ANTIPOLLUTION
Test for the presence of lead
14
METHOD
Detecting lead at the exhaust
a- Conditions for the test:
- Engine not running
- Exhaust pipe warm but not burning.
- Do not perform the test if the temperature is below 0 °C.
b- If necessary, use a dry cloth to clean the inside of the exhaust pipe to remove soot deposits.
c- Wearing the gloves, moisten a test paper slightly with distilled water (if the paper becomes too wet, it
will lose its efficiency).
d- Apply the moistened test paper to the cleaned section of the exhaust pipe and hold it there with
slight pressure for approximately one minute.
e- Remove the test paper and leave it to dry. If lead is present, the paper will be a red or pinkish colour.
ATTENTION :The test for lead should be carried out on the exhaust tail pipe. It should never be carried out
on the oxygen sensor.
Petrol engine
14-22

CHECKING
After 15 minutes warming up with a voltage of13.5 volts.
STARTING - CHARGING
Alternator
16
IDENTIFICATION
ENGINE ALTERNATOR CURRENT
F3R
F8QValéo A 11 VI - 59
Valéo A 13 VI 4575 A
110 A
F3R CA
F8Q CAValéo A 13 VI - 57 110 A
K7MValéo A 11 VI - 61
Valéo A 13 VI 10575 A
110 A
E7J
Valéo A 13 VI 104
Valéo A 13 VI 10580 A
110 A
engine rpm 75 apms 80 apms 110 apms
1000
2000
3000
400046
68
71
7254
75
80
8257
94
105
108
16-1

STARTING - CHARGING
Alternator
16
OPERATION - FAULT FINDING
These vehicles are fitted with alternators with in-
ternal ventilation, an integral regulator and a
warning light on the instrument panel which ope-
rates as follows :
- when the ignition is turned on, the warning
light illuminates,
- when the engine starts, the warning light ex-
tinguishes,
- if the warning light illuminates again when
the engine is running, there is a "charging"
fault.
LOOKING FOR FAULTS
The warning light does not illuminate when the
ignition is turned on.
Check:
- the electrical connections are correct,
- the bulb is not blown (to do this, earth the cir-
cuit; the bulb should illuminate).
The warning light illuminates when the engine is
running
There is a charging fault which could be due to:
- the alternator drive belt being broken or the
charging cable being cut,
- internal damage to the alternator (rotor, sta-
tor, diodes or brushes),
- regulator fault,
- an excess voltage.The customer complains of a charging fault and
the warning light operates correctly.
If the regulated voltage is less than 13.5 V, check
the alternator. The fault could be caused by:
- a destroyed diode,
- a cut phase,
- track contamination or wear.
Checking the voltage
Connect a voltmeter across the battery terminals
and read the battery voltage.
Start the engine and increase the engine speed
until the voltmeter needle stabilises at the
regulated voltage.
This voltage should be between 13.5 V and 14.8 V.
Connect as many consumers as possible, the
regulated voltage should remains between 13.5 V
and 14.8 V.
IMPORTANT: if arc welding is carried out on the
vehicle, the battery and the regulator must be
disconnected.
16-2

STARTING - CHARGING
Alternator
16
- the alternator drive belt, together with bolt (3)
and shaft (4), removing through opening (5),
REMOVAL
With the vehicle on a 2 post lift, disconnect:
- the battery,
- the alternator electrical connections.
Remove:
- the power assisted steering belt by slackening
the three bolts (1) and the nuts (2) for the ten-
sioner, E 7 J and
K 7 M engines
SPECIAL TOOLING REQUIRED
Mot. 1273 Tool for testing belt tension
T. Av. 476 Ball joint extractor
Upper shock absorber mounting bolt 3
Track rod end nut 3.5
Wheel bolts 9
TIGHTENING TORQUES (in daN.m)
98747R198745R2
- the front right hand wheel,
- the track rod end (6) using tool T. Av. 476,
98712R
16-3

STARTING - CHARGING
Alternator
16
- the two upper shock absorber mounting bolts
(7).
98709R1
Press downwards on the front axle assembly to
make removing the alternator easier through the
front right hand wheel arch.
REMOVAL
Refitting is the reverse of removal.
Special notes:
- do not refit the old drive belt, renew it,
- refer to section 07 for tension values. E 7 J and
K 7 M engines
16-4

STARTING - CHARGING
Alternator
16
REMOVAL
(there are no special notes for engines fitted with
power assisted steering)
To release the alternator shaft the following must
be removed:
- the mounting bolts (1) for the coils,
- the two bolts (2) from the coil mounting.
Slacken bolt (3) then slide the mounting down.
98899R1
REFITTING
Refitting is the reverse of removal. F 3 R engine
16-5

STARTING - CHARGING
Alternator
16
REMOVAL
Disconnect:
- the battery,
- the alternator electrical connections.
Remove the mounting bolt for the diesel fuel pipe
retaining bracket and move it to one side.
98837R
Slacken bolt (A) then bolt (B), to just past the
shoulder, while holding the automatic tensioner
plate with a 9 mm wrench (Eg. : FACOM J 151 rat-
chet), then slacken the belt by moving the ratchet
in the direction of the arrow. F 8 Q engine
with AC
98837-1R
Remove:
- the lower timing cover,
- the belt,
- the alternator mounting bolts,
- the alternator.
REFITTING(Special note)
Refitting is the reverse of removal.
The belt is tensioned by moving the automatic
tensioner plate against the stop at bolt (B), wi-
thout forcing it, using a 9 mm wrench (Eg. :
FACOM J 151 ratchet ).
98837-1R1
NOTE : do not refit a belt once it has been remo-
ved.
16-6