Chrysler neon 1997 Service Manual page 505

CATALYTIC EXHAUST MANI- NUT 28 N·m (250 in. lbs.) SHOULDER FOLD VERTER SPRING CON- BOLT
11 - 2 EXHAUST SYSTEM AND INTAKE MANIFOLD
GENERAL INFORMATION (Continued)
Fig. 2 Ball Joint Connection
Fig. 3 Exhaust System Components
CAUTION: Due to exterior physical similarities of
some catalytic converters with pipe assemblies,
extreme care should be taken with replacement
parts.
The combustion reaction caused by the catalyst
releases additional heat in the exhaust system. Caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency. Do not remove spark
plug wires from plugs or by any other means short
out cylinders if exhaust system is equipped with a
catalytic converter. Failure of the catalytic converter
can occur due to temperature increases caused by
unburned fuel passing through the converter.
The use of the catalysts also involves some non-au-
tomotive problems. Unleaded gasoline must be used
to avoid poisoning the catalyst core. Do not allow
engine to operate above 1200 RPM in neutral for
extended periods over 5 minutes. This condition may
INSULATOR BRACKETS OVAL MUFFLER HEAT SHIELD SHOULDERBOLT EXHAUST PIPE SPRING NUT SEAL RING HEAT SHIELD SCREWS
result in excessive exhaust system/floor pan temper-
atures because of no air movement under the vehicle.
HEAT SHIELDS
The heat shield (Fig. 4) is needed to protect both
the car and the environment from the high tempera-
tures developed in the vicinity of the catalytic con-
verter.
Refer to Group 23, Body and Sheet Metal for ser-
vice procedures.
CAUTION: Avoid application of rust prevention
compounds or undercoating materials to exhaust
system floor pan heat shield on cars if equipped.
Light over-spray near the edges is permitted. Appli-
cation of coating will greatly reduce the efficiency
of the heat shields resulting in excessive floor pan
temperatures and objectionable fumes.
Fig. 4 Heat Shield Installation
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
To assist in the control of oxides of nitrogen (NOx)
in engine exhaust, some engines are equipped with
an exhaust gas recirculation system. The use of
exhaust gas to dilute incoming air/fuel mixtures low-
ers peak flame temperatures during combustion, thus
limiting the formation of NOx.
Exhaust gases are taken from the number four
exhaust port through a hole in the end of the cylin-
der head. REFER TO GROUP 25, EMISSION SYS-
TEMS FOR A COMPLETE
DIAGNOSIS AND SERVICE PROCEDURES ON
THE EXHAUST GAS RECIRCULATION SYSTEM
AND COMPONENTS.
UNDER BODY
PL
DESCRIPTION,