United States	EPA 420-F-93-004
Environmental Protection September 1993
Air And Rad at on (6406J)
&EPA Car Owners:
Protect The
And Your
Don't Tamper
With Emissions

Don't Tamper
With Emission Controls!
Do you know that tampering with a car s emission
controls is illegal? This federal law is one of the 1990
amendments to the U S. Clean Air Act You or your
auto mechanic can be penalized as much as $2,500 for
each violation Most states also have laws against tam-
pering, so you might owe additional fines as well
Is getting caught the only reason to avoid tampering?
Absolutely not1 Think about these facts
	Tampering adds to air pollution, because it increases
your car or truck s emissions
	It won't improve your car or truck s gas mileage or
dnveabihty. Instead, adjusting or disconnecting
emission controls is likely to reduce your mileage
and have a negative impact on driveability
	Tampering is expensive If you have a new car or
truck, you paid about $500 for the emission con-
trols When you tamper with them, you are throw-
ing that money away. And tampering will reduce
the trade-in value of your car or truck.
	Tampering will probably reduce the life of your
vehicle's engine.
	Tampering may void your emission control
What Is Tampering?
You are tampering if you remove, bypass, defeat, dis-
connect, damage or in any way render ineffective any
emission control device or element of design that has
been installed on a motor vehicle or a motor vehicle
engine, or have someone else do it for you.
Tampering includes:
	Removing such devices as the catalytic converter, air
pump and EGR valve, or doing anything to them to
keep them from working properly.

	Disconnecting vacuum lines and electrical or
mechanical parts of the pollution control system,
such as electrical solenoids, sensors, or vacuum -
activated valves
	Adjusting any element of a car or truck's emission
control design so that it no longer meets the man-
ufacturer's specifications.
	Installing a replacement part that is not the same
in design and function as the part that was origi-
nally on the vehicle, such as an incorrect exhaust
	Adding a part that was not originally certified on
the car, such as installing a turbocharger
You can avoid making innocent mistakes that could
be tampering, if you simply make all adjustments
according to the manufacturer's specifications, and
install parts designed to properly replace the original
Why Do We Need An
Antitampering Law?
Motor vehicles contribute nearly half the total
amount of man-made air pollution in the United
States today. They emit nearly sixty percent of the
total amount of carbon monoxide, a poisonous gas.
They also emit one-fourth of the hydrocarbons and
nearly one-third of the oxides of nitrogen. These last
two substances are major causes of the unhealthy
smog that hangs over so many cities and suburbs.
Congress established motor vehicle emission stan-
dards for cars and trucks to reduce this pollution and
protect the American public's health. Car and truck
manufacturers are required to certify that their
designs meet these standards.
Tampering changes a car's certified design and caus-
es it to exceed emission standards. EPA surveys show
that tampering is widespread. Some service and
repair shops even claim that removing emission con-
trols improves gas mileage, which is not true.

To put an end to tampering, and to make sure that
cars meet emission standards for as long as they are
being driven, Congress broadened the antitampenng
provision of the Clean Air Act
What Is The Antitampering Law?
The original law was part of the Clean Air Act of
1970 It applied to new cars before they are sold and
delivered to the buyer, and it only affected manufac-
turers and car dealers Violators may have to pay as
much as 525,000 for each new car or truck they tam-
per with
The antitampering law that was included in the 1977
Amendments to the Clean Air Act expanded liability
for violators to include automobile services, repair
facilities, and fleet operators. These facilities can be
penalized up to $2,500 per car or truck that is tam-
pered with.
The 1990 Amendments broadened the tampering
provision even further and now it applies to every-
one, including car owners Anyone who tapipers can
be penalized up to $2,500 per vehicle. Many states
also impose additional penalties
Does Tampering Improve Gas
Mileage and Driveability?
No! Tampering does not improve gas mileage, per-
formance or dnveability. In many cases, it worsens
In cars that were manufactured after 1974, the cat-
alytic converter is the primary means of emission
control. It's important to understand that these
devices do not decrease gas mileage or dnveability
The pollution control systems used in cars since the
mid- 1970's have contributed to a dramatic improve-
ment in fuel economy If you damage or disconnect the
catalytic converter, all you accomplish is to increase air
pollution and waste an expensive piece of equipment

Tampering can shorten an engine's bfe and cause per-
formance problems In today's cars and trucks, emis-
sions control is part of the total design and function
of many of the engines components. This includes all
parts of the fuel, ignition and air management sys-
tem, intake and exhaust manifolds, and the EGR
valve. When the emission control design of one of
these systems or components is changed, perfor-
mance will likely suffer Often, the result is loss of fuel
efficiency and increased emissions Maintenance, fuel
system adjustments, ignition timing, compression
ratio, and EGR can all affect an engine's durability
Cars and trucks should always be properly main-
tained, according to the manufacturers specifications
Can Keeping A Car Well
Tuned Help Gas Mileage And
Emission Control?
Yes' Maintaining your car according to the manufac-
turer's specifications will almost always give you bet-
ter gas mileage and lower emissions. Studies show
that cars that fail the emission test improve their gas
mileage between four and ten percent after their
emission controls are professionally serviced. Keep-
ing your car or truck well tuned, and following the
manufacturers maintenance schedule, are the best
ways to improve its driveability and lengthen the
engine's life.
Yes! Under the Clean Air Act, car manufacturers
must provide warranties that cover emission control
and emission related systems and devices. But if
these components are tampered with, the manufac-
turer may not have to honor the warranty, because
the car has not been properly maintained according
to the manufacturer's specifications.

What Can I Do To Help?
Emission controls are our best bet for reducing pol-
lution Removing them or disconnecting them
defeats a vital aspect of our national program to
clean up the air You can help bv not tampering with
your car or truck's emission controls, and not asking
anyone else to do so Instead, make sure your
mechanic follows the manufacturer's tune-up speci-
fications for best performance and emission control
If you know that an automobile service or repair
facility is breaking the antitampering law, or if you
have any other questions, contact the U S Environ-
mental Protection Agency, Field Operations and
Support Division (6406J), Washington, DC 20460
This document mas he reproduced without charge, in whole or in pjrt. with
out permission, except tor use as advertising material or product endorsement
Anv such reproduction should credit the Amenun Lung Association and (he
L'S Fnuronmtntal Protection Ajiencv fhe use of all or an\ part of this docu
ment in a deceptive or inaccurate manntr or tor purposes ol indorsing a par
titular product may be subject to appropriate legal action
Your cooperation is important Keeping your cars
emission controls working correctly helps protect the air
we all breathe This leaflet was prepared by the Ameri-
can Lung Association and the U S. Environmental Pro-
tection Agency to answer your questions about your
cars pollution controls Please read it carefully
The information m this document has been funded
wholly or m part by the United States Environmental
Protection Agency under assistance agreement CX-
818718-01-0 to the American Lung Association. It has
been subjected to the Agency's peer and administrative
review and has been approved for publication as an
EPA document. Mention of trade names or commer-
cial products does not constitute endorsement or rec-
ommendation for use
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