Sts Acura RL 2004 3.5 Owner's Guide

The exhaust emissions controls
include f our systems: PGM-FI,
Ignition Timing Control, Exhaust
Gas Recirculation and Three Way
Catalytic Converter. These four
systems work together to control the
engine’s combustion and minimize
the amount of HC, CO, and NOx that
comes out the tailpipe. The exhaust
emissions control systems are
separate f rom the crankcase and
evaporative emissions control
systems.
The PGM-FI System uses sequential
multiport f uel injection.
It has three subsystems: Air Intake,
Engine Control, and Fuel Control.
The Powertrain Control Module
(PCM) uses various sensors to
determine how much air is going
into the engine. It then controls how
much f uel to inject under all operat-
ing conditions.This system constantly adjusts the
ignition timing, reducing the amount
of HC, CO, and NOx produced.
The Exhaust Gas Recirculation
(EGR) system takes some of the
exhaust gas and routes it back into
the intake manif old. Adding exhaust
gas to the air/f uel mixture reduces
the amount of NOx produced when
the f uel is burned.
The three way catalytic converter is
in the exhaust system. Through
chemical reactions, it converts HC,
CO, and NOx in the engine’s exhaust
to carbon dioxide (CO ), dinitrogen
(N ), and water vapor.
The emissions control systems are
designed and certif ied to work to-
gether in reducing emissions to
levels that comply with the Clean Air
Act. To make sure the emissions
remain low, you should use only new
Acura replacement parts or their
equivalent f or repairs. Using lower
qualitypartsmayincreasethe
emissions f rom your car.
The emissions control systems are
covered by warranties separate from
the rest of your car. Read your
warranty manual f or more informa-
tion.
2
2
Exhaust Emissions Controls Replacement Parts
PGM-FI Syst emIgnit ion T iming Cont rol Syst em
Exhaust Gas Recirculat ion (EGR)Syst em
Three Way Catalytic Converter
Emissions Cont rols
T echnical Inf ormation346

Always use unleaded gasoline.
Even a small amount of leaded
gasoline can contaminate the
catalyst metals, making the three
way catalytic converter inef f ective.Keep the engine tuned-up.
A defective three way catalytic
converter contributes to air pollution,
and can impair your engine’s per-
f ormance. Follow these guidelines to
protect your car’s three way catalytic
converter. Have your car diagnosed and
repaired if it is misf iring, back-
f iring, stalling, or otherwise not
running properly.
The three way catalytic converter
contains precious metals that serve
as catalysts, promoting chemical
reactions to convert the exhaust
gasses without af f ecting the metals.
The catalytic converter is ref erred to
as a three-way catalyst, since it acts
on HC, CO, and NOx. A replacement
unit must be an original Acura part
or its equivalent.
The three way catalytic converter
must operate at a high temperature
for the chemical reactions to take
place. It can set on f ire any com-
bustible materials that come near it.
Park your car away f rom high grass,
dry leaves, or other f lammables.
Three Way Catalytic Converter
T echnical Inf ormation347
THREE WAY CATALYTIC CONVERTER

If you believe that your car has a
def ect which could cause a crash or
could cause injury or death, you
should immediately inf orm the
National Highway Traf f ic Saf ety
Administration (NHTSA) in addition
to notifying Acura Automobile
Division, American Honda Motor Co.,
Inc.If NHTSA receives similar com-
plaints, it may open an investigation,
and if it f inds that a saf ety def ect
exists in a group of vehicles, it may
order a recall and remedy campaign.
However, NHTSA cannot become
involved in individual problems
between you, your dealer, or Acura
Automobile Division, American
Honda Motor Co., Inc.To contact NHTSA, you may either
call the Auto Saf ety Hotline toll-f ree
at 1-800-424-9393 (or 366-0123 in
Washington D.C. area) or write to:
NHTSA, U.S. Department of
Transportation, Washington,
D.C. 20590. You can also obtain
other inf ormation about motor
vehicle safety from the Hotline.
Reporting Saf ety Def ects (U.S. Cars)
Warrant y and Cust omer Relat ions354