hence the heat shields on the vehicle
underbody - and the casing will become
hot enough to ignite combustible
materials which brush against it. DO NOT,
therefore, park the vehicle in dry
undergrowth, over long grass or piles of
dead leaves.
(k) Remember that the catalytic converter is
FRAGILE. Do not strike it with tools
during servicing work, and take great care
when working on the exhaust system (see
Chapter 4). Ensure that the converter is
well clear of any jacks or other lifting gear
used to raise the vehicle. Do not drive the
vehicle over rough ground, road humps,
etc, in such a way as to “ground” the
exhaust system.
(l)
In some cases, particularly when the
vehicle is new and/or is used for
stop/start driving, a sulphurous smell (like
that of rotten eggs) may be noticed from
the exhaust. This is common to many
catalytic converter-equipped vehicles,
and seems to be due to the small amount
of sulphur found in some petrols reacting
with hydrogen in the exhaust, to produce
hydrogen sulphide (H
2
S) gas; while this
gas is toxic, it is not produced in sufficient
amounts to be a problem. Once the
vehicle has covered a few thousand miles,
the problem should disappear - in the
meanwhile, a change of driving style, or of
the brand of petrol used, may effect a
solution.
(m) The catalytic converter on a well-
maintained and well-driven vehicle should
last for between 50 000 and 100 000
miles. From this point on, careful checks
should be made at regular intervals to
ensure that the converter is still operating
efficiently. If the converter is no longer
effective, it must be renewed.
Checking
7 Checking the operation of a catalytic
converter requires expensive and
sophisticated diagnostic equipment, starting
with a high-quality exhaust gas analyser. If the
level of CO in the exhaust gases is too high, a
full check of the engine management system
must be carried out (see Section 3 of this
Chapter) to eliminate all other possibilities
before the converter is suspected of being
faulty.
8 The vehicle should be taken to a Ford
dealer for this work to be carried out using the
correct diagnostic equipment; do not waste
time trying to test the system without such
facilities.
Component renewal
9 The catalytic converter is part of the
exhaust system front downpipe - see Chap-
ter 4 for details of removal and refitting.
6•20 Emissions control systems