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1973 OPEL SERVICE MANUAL
EMISSION CONTROL SYSTEMS
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Description and Operation of O.E.C.S.
. . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Gas Recirculation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DIAGNOSIS:
Testing
Air Cleaner Operation . . . . . . . . . . . . . . . . . . . . . .
Exhaust Gas Recirculation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE AND ADJUSTMENTS:
Exhaust GAS Recirculation System . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAJOR REPAIR:
Removal and Replacement of O.E.C.S. Units
. . . . . . . . . .
SPECIFICATIONS:
Opel Emission Control System Specifications . . . . . . . .
Page No.
DESCRIPTION AND OPERATION
OPEL EMISSION CONTROL SYSTEM (O.E.C.S.)
All 1973 cars must be capable of passing certain tests
which measure the quantity of unburned impurities
in the exhaust system. Federal law places a limit on
the hydrocarbon and carbon monoxide emissions
from the exhaust system. The purpose of this law is
to keep the atmosphere cleaner, particularly in popu-
lous areas where these impurities add to the smog
problem. Basically, excessive exhaust emissions are
caused by incomplete combustion of the air-fuel mix-
ture in the cylinders.
The basic components of the OECS on the 1.9 liter
engines are (1) leaned out carburetion, (2) heated air
(except GT), and (3) tuned spark timing.
(1) The carburetor idle system is leaned out and
special features are incorporated into the carburetors
to make possible additional idle mixture adjustments
over and above those manufactured into the carbu-
retors.
(2) The heated air package consists of a heat stove,
a corrugated paper heated air pipe, and an air cleaner
containing a temperature controlled door operated
by
through a temperature sensor. See Figure
The heat stove is a sheet metal cover, shaped to and
bolted onto the exhaust manifold. Air drawn in along
Figure
Heated Air System Installed
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